General requirements for mix production and for the construction of asphalt concrete pavement courses are included in 401 or 441, depending on the contract item designation. 401 covers construction requirements, while 441 covers mix design and quality control requirements. Specification requirements for the specific pavement courses are found in the specifications under the contract item designation.

Asphalt concrete is a mixture of aggregate and asphalt material. The asphalt material used in these mixtures has a relatively high viscosity at normal temperatures. Because of this, it is necessary to heat the aggregate and asphalt material to permit mixing, placing, and compacting.

Asphalt concrete may be used in new construction as the entire pavement structure or it may be used in conjunction with other materials in a layered pavement structure. Extensive use of asphalt concrete is also made for rehabilitating existing pavements by resurfacing or widening and resurfacing. Asphalt concrete is particularly adaptable to this type of work, where disruption of normal traffic flow must be kept to a minimum. Although written with reference to new construction, the instructions contained herein also apply to rehabilitation construction.

Asphalt concrete mixtures are produced in a central proportioning and mixing plant. At the plant, aggregate is dried and heated to the mixing temperature and mixed with the specified asphalt material. On completion of mixing, the mixture is discharged directly into trucks or conveyed to a surge bin from which trucks are loaded for transport to the project.

Asphalt concrete is placed by use of various types of mechanical pavers or by hand methods. After it is placed, the mixture must be compacted using the proper compaction equipment before it cools and becomes unworkable.

Mixture Production Inspection (401.02, 401.05)

Initial Plant Inspection and Mix Design

Laboratory personnel must inspect and approve the mixing plant proposed by the Contractor prior to the production of any asphalt concrete.

The Laboratory also establishes composition limits for any asphalt concrete mixture established in accordance with 401.02 prior to the start of production. The mixture composition data for the specific contract item is transmitted from the Laboratory to the plant inspector. The job mix constants included in this data can not be changed by the plant inspector without prior approval by the Laboratory.

The Contractor performs a mix design process, approved by the Laboratory, to determine the composition limits for any asphalt concrete mixture established in accordance with 441.

Field Inspection

The inspector assigned to the placing of asphalt concrete should observe closely the placing of the initial production of each type of mixture for indications of deficiencies in the mixture composition. If the mixture appears to be deficient in any of the following respects, notify the District plant monitor and the Contractor immediately, and note on the Inspector’s Daily Report. In some cases, production should cease immediately.

Segregation

The coated aggregate particles should appear to be uniformly graded in size from coarse to fine.

Mixture Consistency

The mixture should have sufficient cohesion to remain mounded in the vehicle during hauling, but should flow freely from the vehicle when the load is dumped.

Stability

The mixture should have sufficient stability for compaction without excessive displacement.

PG (Asphalt) Binder Content

The mixture should contain enough PG (Asphalt) binder (which binds the aggregate particles together as the mixture is compacted) without producing a glazed or flushed appearance.

Temperature

Variations in the temperature of asphalt concrete loads can often be detected simply by comparative observation, and then substantiated by actual temperature measurement. In extreme cases, a hot load will give off a blue smoke while a cold load will be partially congealed (change from a fluid to a solid state) and will not flow freely. By close observation of the flow of the asphalt concrete from the truck bed into the paver hopper, the inspector can learn to judge the temperature of the material quite accurately.

Mixture Proportions

Excessive fluctuations in PG binder content, changes in the proportion of the coarse and fine aggregate, and non-uniform mixing can be detected by observation. Notify the plant monitor.

Moisture

Variations in the moisture content of the aggregate fed to the plant or an erratic production rate may result in an excess of moisture in the asphalt concrete mixture. This can cause slumped or flattened loads, accompanied by considerable bubbling or steaming of the mixture. In extreme cases, the PG binder material may separate from the aggregate and collect in a film over the surface of the load. This condition is unacceptable and is sufficient cause for rejection of the load. Excess moisture may also cause streaks of excess PG binder material to appear as the mixture is spread. These streaks should be eliminated immediately by remixing the material using a rake. The District plant monitor should be notified of this condition.

Contamination

An asphalt concrete mixture can become unsatisfactory due to contamination of the PG binder material, the aggregate, or the mixture itself. Contamination of the PG binder material, either in shipment or in storage at the plant, usually has the most serious effects. Contamination of the PG binder material may remain undetected until a quantity of mix is produced, at which time a marked change in the odor, consistency, or appearance of the mixture in the truck or in the paver hopper indicates that such contamination has occurred. When these changes are noted, observe the mixture carefully as it is being placed and compacted. If the mixture is unusually soft and unstable or tends to flush, the material is unsatisfactory and must be removed and replaced with acceptable material.

Contamination of small portions of the asphalt concrete mat may occur due to bed hoist leakage, spillage of fuel or lubricants, or foreign matter on the surface. These areas should be corrected by removing the contaminated material and replacing it with acceptable material.

As the placing of the asphalt concrete progresses, the inspector should continue to observe the mixture being delivered to the paver since irregularities in proportioning, mixing, and temperature control may occur. The results of such irregularities may not be detected at the plant and an unsatisfactory load of asphalt concrete may arrive at the paver.

Mixture in the hauling vehicle that is out of specification limits must be rejected in borderline cases. The material may be placed with acceptance based on the appearance of the material under the action of the compaction equipment. If the mixture is unsatisfactory, it must be removed and replaced with acceptable material. When the field inspector rejects a load of material, this action must be recorded on the plant ticket form, along with the reason for rejection. Also, the District plant monitor and contractor’s quality control technician should be informed of the quantity of the material rejected and the reasons for rejection.

Weather Limitations (401.06)

Paving operations must not be permitted when the surface temperature of the existing pavement at the site is below the minimum specified in 401.06. Air temperature requirements for surface courses and courses paved directly on an aggregate base, subbase, or subgrade are also specified in Table 401.06-1.

Table 401.06-1
Course Thickness	Minimum Surface Temperature
3.0 inches (75 mm) and over	36 °F[1]	(2 °C[1])
1.5 to 2.9 inches (38 to 74 mm)	40 °F	(5 °C)
1.0 to 1.4 inches (25 to 37 mm)	50 °F	(10 °C)
Less than 1.0 inch (25 mm)	60 °F	(16 °C)
Variable Intermediate, 0 to 3.0 inches (0 to 75 mm)	40 °F	(5 °C)
[1] Instead of 36 °F (2 °C), use a minimum air temperature of 40 °F (5 °C) if paving on an aggregate base or subgrade.

In addition to the above surface temperature requirements, do not place surface courses if the air temperature is less than 40 °F (5 °C).

For Type 1H asphalt concrete or any surface course with a polymer modified asphalt binder, ensure that the surface of the existing pavement is at least 50 °F (10 °C) and the air temperature is at least 50 °F (10 °C).

Do not place any Type 1H asphalt concrete or any surface course with a polymer modified asphalt binder after November 1, regardless of pavement or air temperature.

Surface temperature measurements should be taken using the following procedures:

1. When taking a reading in the sun, place the thermometer on the pavement and then shade that area with a clipboard, cardboard, or other available shading material. Then take the temperature reading after approximately 3 minutes. The intent is not to shade the area to allow it to cool, but to protect the thermometer from obtaining a false reading due to direct exposure to the sun.

2. The surface temperature should not be taken under the only shade tree or at the only sunny (unshaded) spot on the project. The surface temperature should be taken at a representative area.

3. The surface temperature should be taken in the lane to be paved and not the adjacent berm.

4. On portland cement concrete pavements where flexible repairs have been performed, the surface temperature of the portland cement concrete will be the governing temperature.

5. A new surface temperature should be taken when the existing pavement surface material changes (asphalt concrete to portland cement concrete or Portland cement concrete to asphalt concrete) to ensure that the new surface meets the minimum temperature specification. If this specification is not met, paving operations must be discontinued until the surface reaches specification temperature. Or, paving operations may be moved to a different area of the project where the surface meets minimum specification temperature.

The placing of thin surface courses at temperatures near this limit may require the Contractor to employ special precautions to produce a satisfactory surface. These precautions include avoiding paver stops, keeping the rollers close to the paver, and providing proper insulation for the truck hauling the material.

The paving operation must be stopped in the event of rain. It is the inspector’s responsibility to order paving operations to be halted and the Contractor’s responsibility to stop plant production. A load of material in the process of being dumped into the paver may be placed, with the requirement that the rollers follow closely behind the paver and a construction joint is formed at the end of the run. Loads waiting to be dumped, however, must not be allowed to be placed. The material in the waiting trucks will retain sufficient heat for proper placing and compacting for an hour or more. Water can be kept from accumulating on the covers of the trucks and draining into the asphalt mixture by raising the truck beds slightly. These loads may be placed when conditions improve and the surface being paved is reasonably dry and in an acceptable condition.

Notification (401.07)

The contractor should notify the Engineer at least 24 hours before starting paving on a project. It is a recommended practice for the Engineer to call for a meeting to discuss material and equipment to be used.

Hauling (401.11)

Included in the specifications (401.11) are the requirements concerning the condition of the vehicles used to haul asphalt concrete mixtures and the distance the mixture may be transported.

The inspector should check the trucks for compliance with the specifications as they arrive at the paving site. In particular, the inspector should observe the following:

1. The bed cover is in good condition.

2. Small portions of the load are not isolated from the mass on projections such as extensions over cabs.

3. The load is discharged evenly, without surging in the paver hopper, and without jogging the vehicle when it is in contact with the paver.

4. As the bed is raised, it does not come in contact with the rigid parts of the paver.

5. Uniform contact between the truck and the paver is maintained as the paver pushes the truck during unloading.

6. Excess coating material is not being used.

7. Diesel fuel is not being used as a coating material.

8. When insulation is required, check to see that all trucks are properly insulated and permit only approved trucks to be loaded.

The inspector should notify the Contractor when deficiencies are found. When corrections are not satisfactory and difficulties persist, the vehicle in question should be removed from the project.

Spreading Equipment (401.12)

Asphalt pavers shall be self-propelled mechanical spreading and finishing equipment, provided with a screed or strike-off assembly capable of distributing the material to the full width of a traffic lane. The type of equipment suitable for spreading asphalt concrete depends on the particular paving operation to be performed, mainline, widening, berm, intersections, and whether the pavement course to be placed is base, intermediate, or surface. Spreading equipment requirements are stated in 401.12.

The contractor should use means and methods approved by the asphalt spreader manufacturer consisting but not limited to any combination of chain curtains, deflector plates, or other such devices that will eliminate segregation.

The contractor should inform the Office of Materials Management of all asphalt spreader equipment purposed for use on ODOT projects. Information should include the spreader make, model, serial number and manufactured year. The list of the approved spreaders will be posted on ODOT web site.

The contractor should submit to the Engineer a certification statement stating that the paver to be used is modified and approved as per 401.12.

Pavers that leave ridges, indentations or other marks in the surface shall not be used unless the ridges, indentations or other marks are eliminated by rolling or prevented by adjustment in operation.

The basic types of pavers found in current practice are described in the following paragraphs:

Floating Screed Asphalt Paver

The standard asphalt paver has long been accepted for placing all courses of asphalt concrete. The standard asphalt paver consists of a tractor with a receiving hopper, a conveying and distributing system, and a floating screed. The screed is essentially a rectangular trowel which floats on the surface of the asphalt mixture. The tractor pulls the screed by means of two shafts or arms hinged to each side of the tractor. Thickness of placed material is regulated by adjusting the angle of the screed with respect to the arms. This adjustment causes the screed to rise or descend until a condition of equilibrium is reached. Vibrating or tamping devices on the screed maintain a uniform flow of mixture under the screed. A heating system is provided to bring the screed to operating temperature at the beginning of work and to maintain proper screed temperature in cool weather.

The paver must have an automatic control system that maintains the screed in a constant position relative to grade, profile, and cross slope references. These references must be capable of controlling the screed position independent of irregularities in the underlying surface and the paver operation.

When paving in excess of the nominal paver width, only a screed extension that have the ability to heat with full auger extensions, should be used when matching a previously placed pavement course. Strike-off plates may be used on adjacent berm areas.

Off-Set Blade Strike-Off Paver

Spreading equipment having a hopper from which material is conveyed to a side-mounted blade strike-off is used to place asphalt concrete for pavement widening, berm paving, and other applications where a relatively narrow width is to be placed. The tractor to which the hopper is attached operates on the surface adjacent to the area being paved. The blade is attached to the tractor and is adjustable as to width, elevation, and cross slope.

Motor Grader

The standard motor grader, when properly equipped to contain the material within the required width, places asphalt concrete satisfactory in patching, spot leveling, and in crown correction work.

Approval of any of the previously described spreading equipment for use on asphalt concrete construction should be based mainly on observation of the quality of previous work completed and current performance. The following items should be observed when considering approval:

1. Equipment must have sufficient size, power, and stability to receive the asphalt concrete material without erratic operation.

2. Equipment must be capable of placing the material accurately in regard to line and grade.

3. Asphalt concrete must be fed uniformly across the width of the screed or strikeoff without surges (which produce corresponding roughness in the finished surface).

4. Asphalt concrete mixture behind the screed or strike-off must have a uniform appearance across the full width of the course.

It is the Contractor’s responsibility to make any necessary adjustments in the paver operation. The inspector, however, should be familiar with the working of the paver, the effect of wear on paver operation, and the effect of various paver adjustments on the placing operation.

Rollers (401.13)

Compaction of asphalt concrete is governed by 401.16 or 446.05, depending on the specified contract item designation. Two types of rollers, steel wheel and pneumatic tire, are specified for use and the requirements for the rollers are found in Tables 401.13-1, 401.13-2 and 401.13-3.

All rollers proposed for use in the compaction of asphalt concrete material must be inspected for compliance with the specifications before paving begins.

Steel drums and wheels should have the necessary accessories to prevent adhesion to the mixture; they should be kept properly moistened with water, water containing a detergent, or water containing an approved additive. Excessive use of liquid should be prohibited.

Pneumatic tire rollers used should be self-propelled, reversible units with vertical oscillation on all wheels on at least one axle.

The contractor should determine the tire inflation pressure necessary to meet the specified minimum contact area and contact pressure requirements.

The contractor should furnish the tire manufacturer’s charts or tabulations to the Engineer for verification of the required inflation pressure.

Tire inflation pressure should be maintained within 5 pounds per square inch (35 kPa) of the required pressure.

Approval of specialized equipment proposed for compaction in areas inaccessible to the specified rollers should be based on obtaining equal results.

Table 401.13-1 Roller Capacity

Roller Type	Maximum Capacity square yards per hour (m²/hr)
Tandem	700 (600)
Three-Wheel	700 (600)
Trench	15 per inch width (13 per 25 mm width)
Pneumatic Tire, Type 1	1000 (850)
Pneumatic Tire, Type 2	700 (600)
Vibratory, Vibrating Roll	15 per inch width (13 per 25 mm width)
Vibratory, Static Roll (not vibrating)	3 per inch width (3 per 25 mm width)

Table 401.13-2 Steel Wheel Rollers

Roller Type

Three-
Wheel

Tandem

Vibratory
Static

Trench

Total weight, tons
(metric tons)

(9)

8 to 12

(7 to 11)

8 to 12

(7 to 11)

Compression rolls, pounds per inch width (kN/m), minimum

300

(53)

200

(35)

120

(21)

300

(53)

Table 401.13-3 Pneumatic Tire Rollers

Type I
Tire size, minimum	9.00 ´ 20 in (229 ´ 508 mm)
Wheel load, minimum	5000 lb (2250 kg)
Average tire contact pressure, minimum	85 psi (590 kPa)
Type II
Tire size, minimum	7.50 ´ 15 in (191 ´ 381 mm)
Wheel load, minimum	2000 lb (900 kg)
Average tire contact pressure, minimum	55 psi (380 kPa)

Preparation of the Surface (401.14)

Cleaning the Surface

The surface on which an asphalt concrete course is to be placed must be free from material accumulations that would contaminate the mixture, prevent bonding, or interfere with placing operations. The surface of the existing pavement should be inspected before the paving operation begins, and should be cleaned of all foreign material, in accordance with 401.14. The surface also should be checked a short distance in front of the paver to assure that the surface has not become contaminated during the construction operation. A dirty or very dusty surface reduces the ability of the tack coat to bond, resulting in a potential slippage plane between the existing surface and the asphalt overlay.

Maintenance of Previously Constructed Surfaces

Prior to placing asphalt concrete on a pavement course constructed under the contract, the condition of this previously-approved work should be observed. Where the approved subgrade or pavement course has become loosened, rutted, or otherwise defective, the deficiency must be corrected before the placing of a subsequent course is permitted. Hauling of materials over an asphalt concrete base course, for example, may cause cracking when there is not sufficient pavement to carry such loads or where excessive deflection occurs over soft areas developed in the subgrade. Where cracking of the pavement occurs in such a case, the strength due to slab action is destroyed, and the affected material must be removed and replaced after correcting the cause of the failure.

Coating of Vertical Faces

The specifications require all vertical faces, with which the asphalt concrete will come in contact, to be coated with asphalt material of a type specified in 401.03. The purpose of this requirement is to provide some additional asphalt material to improve the bond of the asphalt concrete to other structures, such as gutters, curbs, catch basins, and all existing pavements. Because of the small quantity of material involved, approval of the asphalt material for this purpose may be based on field inspection. The results of this inspection are recorded on the Inspector’s Daily Report, with the material identified as to type, grade, manufacturer, and use.

Before placing a surface course onto an intermediate course, apply a tack coat to the intermediate course according to 407.06.

Spreading and Finishing (401.15)

Correcting Existing Surface Irregularities

In contracts which include rehabilitation of the existing pavement by resurfacing, a quantity of asphalt concrete is usually provided in the plans for making spot corrections or for placing a continuous intermediate course to correct the cross-slope and profile of the existing pavement, as directed by the Engineer. The placing of this corrective material should be controlled closely to assure that the best possible riding quality is obtained in the completed pavement.

Spot corrections, when provided for in the plans, are made to correct irregularities in the existing pavement which would not be corrected satisfactorily due to their magnitude during the placing of the overlaying intermediate or surface course. Deficiencies in the surface requiring spot correction should be located, and the Engineer should notify the Contractor of the required corrective measures. In making these spot corrections, the mixture should be alternately placed and compacted until the profile and cross-slope conforms to the surrounding pavement. Interior edges of these patches may be irregular, but outside edges must conform to the specified edge alignment. All spot corrective work must be completed to the satisfaction of the Engineer before the intermediate or surface course may be placed.

An intermediate course of asphalt concrete, when specified, is used to correct minor irregularities in the existing pavement surface. As mentioned above, spot correction may be needed prior to placing the intermediate course since this course cannot be expected to cover or correct major deficiencies. The paver used to place the intermediate course has a self-leveling action that tends to correct these small irregularities. In addition to this action, automatic control of the paver screed compensates for these irregularities. Inspect the placing of the intermediate course to assure that all deficiencies have been corrected satisfactorily. For intermediate courses where the profile or cross-slope is not specified on the plans, the profile of the new course should provide for a smooth riding surface, and the cross slope should be uniform on all tangent sections and should vary uniformly in transition sections into superelevated sections. For an intermediate course where the profile or cross-slope is specified, the new course should conform to the required profile and cross-slope, within the specified limits. The procedure for checking the profile and cross-slope is given in Section 401.19.

Checking Spreading Methods

Inspection of the asphalt concrete spreading consists primarily of observing the methods and practices being used by the Contractor. It is the inspector’s responsibility to assure that these methods are producing the intended results and to require any corrective measures necessary if unsatisfactory results are obtained. Regardless of the method of placing used, mechanical or hand, the following conditions should be checked closely:

1. Uniformity of the mixture and any evidence or segregation

2. Surface texture of the mixture

3. Temperature of the mixture

4. Edge alignment of the material

The inspector should observe the spreading operation for any signs of segregation of the mixture. The accumulation of coarse aggregate in pockets across the width of the spread mixture is undesirable; particularly so when these pockets occur along the edges. Methods or practices causing segregation must not be permitted to continue.

Hand placing and leveling tend to segregate the mixture by working the coarse aggregate particles to the surface. Surface courses placed by hand must be given particular attention because of appearance and the fact that the segregated areas are very susceptible to raveling. Only a dense, uniform surface texture is acceptable. Since an unsatisfactory surface texture may not be evident until after a roller pass, the inspector must insist that workers and material are available during rolling of hand-placed areas to make any needed correction. Segregated areas should be corrected by placing additional material and raking out the coarse particles, leaving the fine particles to form a dense surface.

Disturbance of the paver operation, due to bumping of the paver by the hauling vehicle or uneven flow of material into the paver hopper, can cause irregularities in the surface being placed. The hauling vehicle should come in contact with the paver with as little shock as possible and, if the hauling vehicle is pushed by the paver during unloading, a constant contact pressure should be maintained in order to avoid jerking the paver. The asphalt concrete should flow uniformly from the truck into the hopper with the quantity in the hopper being maintained at a uniform level. Sudden surges of material affect the position of the strike off, causing surface irregularities.

The mixture should have a uniform appearance across the width placed. Streaks of differing texture and pulling or tearing of the mixture generally indicate the need for adjustments to the paver screed or strike off, or that differential wear has occurred in these parts. This also may be due, however, to low temperature or to mix deficiencies.

The placing of asphalt concrete mixtures, particularly in a thin surface course susceptible to rapid loss of heat, must be done in such a manner that compaction can follow before the mixture cools below a workable temperature (175 °F – 275°F). Lower compaction temperatures are directly related to an increase in air void content, which decreases the strength of the pavement. Even with a perfect mix design, if the mix is not properly compacted in the field, the final product will not last for its intended length of time. This is important especially in small areas where the mixture is placed by hand. In these areas, heating of the underlying surface with torches or radiant heaters helps reduce the loss of heat from the mixture to this surface. Although not a recommended practice, heat can also be applied to the material being placed in order to maintain the mixture at a workable temperature. This practice must be controlled carefully to prevent damage to the mixture. Any mixture that cools before it can be compacted properly must be removed and replaced.

The inspector should use a straightedge to check the surface of the loose material cross slopes.

The inspector should calculate the required spreading rate in tons per station and ensure that the actual spreading rate is within +5%. See Example in 301.05.

Nighttime Paving

When nighttime paving is allowed, the contractor should provide site lighting. This work consists of furnishing, installing, operating, maintaining, moving, and removing night time lighting to illuminate construction work areas for night work. Night work is defined as work performed from 30 minutes before sunset to 30 minutes after sunrise.

The Contractor should provide an illuminated zone of at least 5 Foot-candles (55 lux) in the immediate vicinity of pavers, rollers, grinding equipment, material transfer vehicles etc and at least 1 Foot-candle (10 lux) light at 25 feet from any equipment.

The Engineer will approve of the lighting before starting the paving operation based on illuminance measurements taken at a height of 20 inches (500 millimeters) above the roadway.

The Contractor should replace non-functioning lamps immediately. Check the luminaire aiming daily. Clean the luminaires regularly. Correct any deficient lighting within one hour or the Engineer will terminate construction activities. The contractor should remove lighting units from the roadway and shoulders when not being used.

The Department will pay for all labor, equipment and materials at the lump sum contract price for item 614 maintaining traffic.

Night asphalt paving should be reviewed/ inspected each day in the daylight for asphalt problems like segregation, smoothness etc. This will help eliminate long periods of poor paving going on without being caught.

District asphalt production monitors will occasionally visit the job to review with the inspector progress and placement issues, and focus on often missed items and help expose and correct problems.

Compaction (401.16)

The compaction of asphalt concrete mixes is currently governed by one of two types of specifications. A method specification is used by some asphalt concrete specifications (301, 302, 448, etc.), while many mix types (441, 442) can be governed by a density acceptance specification in accordance with 446.05. The majority of compaction should be accomplished before the temperature reaches 225 ºF and while the mix is still in a plastic state.

Compaction (Method)

This section pertains to the compaction of all asphalt concrete mixes, except for asphalt concrete mixes accepted in accordance with 446.05. Compaction of mixes accepted in accordance with 446.05 is described in section Compaction (Density Acceptance). Compaction of an asphalt concrete mixture using the method specification is performed by using the rollers and methods specified in 401.13 and 401.14.

The number and type of rollers proposed for use by the Contractor should be checked for compliance with 401.13. The calculation for the rollers capacity (tons per hour) should be made by the project personnel. See the example in 301.04. Documentation of the calculations and the tire manufacturer’s charts or tabulations furnished by the contractor should be kept in the project files. As the work progresses, the placement rate should be checked to assure that it does not exceed the combined capacity of the rollers in use. If the placement rate does exceed the roller capacity, the Contractor must either reduce the rate or use additional rollers.

For compacting base mixtures, the specifications require at least one steel and one Type 1 pneumatic tire roller. This requirement must be met even though the placing rate may indicate the need for only one roller. The intent is to assure that each layer of base mixture will be subjected to the traffic conditioning effects of pneumatic tire rolling while the mixture has sufficient retained heat to respond without fracturing.

Compaction (Density Acceptance)

This section pertains to the compaction of asphalt concrete mixes accepted in accordance with 446.05. Compaction of all other mixes is described in section 401.16.

Compaction of an asphalt concrete mixture accepted in accordance with 446.05 is obtained by using rollers meeting the minimum requirements specified in 401.13. Since the Contractor is responsible for choosing the roller train and obtaining density in accordance with 446.05, the maximum roller capacities specified in 401.13 and all but the last four paragraphs of 401.16 are waived.

General Compaction Inspection

This section pertains to the compaction of asphalt concrete mixes using either the method specification or the density acceptance specification (described above). The inspector should refer to the last four paragraphs of 401.16 to review the common part of both compaction specifications.

The optimum compaction conditions are present immediately behind the paver, and the greatest increase in density per roller pass occurs in this area. It is important, therefore, that the initial or breakdown roller follows the paver as closely as possible. When an intermediate roller is used, it should follow the initial roller closely in order to provide the required overlapping coverage. The timing of the final rolling, required for removal of any roller marks, depends on the condition of the mixture. Regardless of their position in the compaction sequence, however, the rollers should be in continuous operation during the spreading process except for necessary stops for fuel and water. The specified roller pattern should be repeated uniformly, without abrupt stops or changes in direction, and the reversing points at the end of the roller runs should be staggered to reduce the possibility of forming transverse bumps.

The unconfined edges (longitudinal joint is a form of an unconfined edge) of the mat should be rolled first using a steel drum roller with the roller drum hanging out in air around 6 inches from the unconfined joint. Best results in compacting the longitudinal joint is by using a drum vibratory roller operated in the vibratory mode and the frequency is set at maximum, the roller drum should be hanging 6 inches in the air. Pneumatic tire rollers should not be used to do this first pass. Use the same rolling procedure when placing the matching mat. Since the material will be confined, using Pneumatic tire roller will be beneficial, if the center of the outside tire is placed over the joint.

Proper Edge Rolling Technique

The inspector must not hesitate to require correction of any defects which appear during the compaction operation, particularly during the construction of surface courses. Deficiencies can be corrected with better results and with less effort during the compaction operation, while the mixture is still hot, than after final compaction and cooling of the mixture.

Joints (401.17)

Longitudinal Joints

Longitudinal joints in the top layer shall correspond with the edges of proposed traffic lanes. Longitudinal joints in lower layers shall be offset as per standard drawing BP-3.1 alternating each side of the edges of traffic lanes not less than 6 inches (150 mm).

Proper longitudinal joint construction requires the loose asphalt concrete material to be “set up 25% extra thickness for roll down and 1 inch to 1½ inch overlap” above the adjacent material to permit proper compaction. If the joint is being made against sawed or milled vertical edge, the overlap must be around ½ inch. This height must be sufficient to permit full compaction of the material being placed before the weight of the roller begins to be carried on the adjacent construction. This pre-compaction height must be maintained uniformly, particularly on surface courses where raveling of an unsound joint is likely to occur. Height uniformity is achieved by continuous manual control or by automatic control of the strike off height.

The paver should be operated in a straight line to provide a mat with a straight edge that can be consistently overlapped. . Excessive deviations of the edge line from a straight line are unacceptable, and require trimming the edge before the adjacent material is placed. With a good edge and proper control of the placing operation, little or no hand work is needed to form a good longitudinal joint. The contractor should not continuously rack the joint. Irregularities in the edge line may require continuous hand raking, however. On surface courses, the inspector must be sure that the hand raking process does not produce an irregular surface texture.

The specified time limit for making a longitudinal joint in the surface course when traffic is maintained is intended to reduce distortion and sealing over of the exposed face. When the Contractor fails to meet this requirement due to unforeseen conditions such as weather or equipment failure, the joint face should be inspected and special precautions taken to assure that a dense, well bonded joint still can be constructed. Trimming of the joint face may be necessary in some cases.

Coating the face of the longitudinal joint is required for all surface courses or any course which is open to traffic more than 30 days, as specified in 401.17.

Transverse Joints

Transverse joints occur at any time the paving operation is interrupted. When placing the last load of asphalt concrete for the day, the paver should move forward until all material is spread. This leaves an irregular end that should be squared off by hand to form the joint. This joint edge should be compacted thoroughly, with the rollers passing over the edge even though this may cause some rounding or even displacement of the material in the process.

When the paving operation resumes, locate the point where the rounding or other departure from the profile begins, and continue the paving operation from that location in order to assure a smooth transition from one section to the other. In some cases, trimming the joint face may be necessary. The joint face should be coated in accordance with 401.17. The Contractor must have workers and hot material available during construction of the joint, utilizing alternate rolling, the use of a 10 foot straightedge, and the addition or removal of material to produce a uniform profile. Paving operations should not be permitted to continue until a satisfactory joint has been obtained.

Checking Pavement Tolerances (401.19)

Checking Line

In new construction, asphalt concrete mixtures are placed on top of a prepared subgrade, subbase, or base course. The placing must be controlled accurately so that the new pavement will conform to the required plan lines. The Contractor sets line and grade stakes prior to the paving operation to aid in placing control and to provide inspectors with reference points to check the conformity of the asphalt surface to the plan profile grades. The contractor will use sensors and long skis gliding over the surface to be overlaid to control the mat thickness and provide a smooth surface. Sometimes specially when matching the approach slabs, the contractor will need a guide or string line as a reference. The paver follows this string line and provides smooth transition.

Paver Using Adjacent Pavement

The edge of the existing pavement may be used as the required reference if it is straight and uniform. If the edge is unsatisfactory for this purpose, the Engineer should direct how the reference is established

Checking Profile

For all new construction, and some rehabilitation construction, the required profile grade and pavement elevations are given in the plans. Where a profile grade is not specified for rehabilitation construction, the profile of the finished pavement surface depends upon the corrected profile of the existing pavement surface. The methods for correcting the profile of the existing surface are given in 401.19.

For construction where a profile grade is specified, the Contractor is required to set grade stakes in order to provide a reference for controlling the elevation and grade at which the asphalt concrete is placed. These grade stakes should be set at intervals of not more than 50 feet (15 m) on tangents and not more than 25 feet (7.5 m) on vertical curves and transition lengths of superelevated curves. The stakes should be placed on both sides of the pavement to permit easy checking of the grade; intermediate stakes should be provided as needed in areas of greater than normal width.

The specifications require the completed pavement profile to be parallel to the plans proposed profile within a specified tolerance. The tolerance is specified in 401.19. The difference in pavement elevation may be obtained by methods such as profile levels or differences in rod readings. Prior to placing the surface course, the Contractor must check the profile of the preceding course and submit a tabulation of the results to the Engineer for approval. The results should be tabulated in a convenient form, listing the following:

1. Station

2. Pavement elevation

3. Plan elevation

4. Difference

The Engineer must evaluate the Contractor’s profile check. Approval of the profile and permission to place the surface course should be based on satisfactory completion of any corrective work needed for compliance with the profile requirement. The approved profile check should be part of the project record.

Checking Cross-Slope

For all new construction, and some rehabilitation construction, the required cross, or transverse, slope of the asphalt concrete pavement is given either as crown or as superelevation in the plans. Where a cross-slope is not specified for rehabilitation construction, the cross-slope of the finished pavement depends on the corrected cross-slope of the existing pavement surface. The methods for correcting the cross-slope of the existing pavement are given in 401.14.

For construction where cross-slope is specified, the specifications require the pavement to be constructed to the specified cross-slope within a given tolerance. The Contractor should check the cross-slope of the pavement course being placed during the spreading operation. The inspector should observe this checking regularly to assure that the pavement course is being constructed substantially within the specified cross-slope limits.

Particular attention should be given to the checking of the cross-slope on the asphalt concrete course preceding the surface course. Where observation of the Contractor’s checking or additional checking by the inspector reveals substantial deviations from the specified limits, corrections must be made to bring the asphalt concrete course within the specified cross-slope limits before the surface course can be placed.

Checking Surface Smoothness

The required smoothness of asphalt concrete pavement courses is specified in terms of an allowable tolerance from the testing edge of a 10 foot (3.0 m) straightedge. The Contractor should check the course being placed while the inspector observes. The frequency of checking depends on the nature of the work being done. No checks of the smoothness need to be made when the paving operation is progressing uniformly. The surface smoothness should be checked closely when a transverse joint is being made, when erratic paver operation occurs, or when hand placing is required in construction of a transverse joint.

The completed surface course will be checked in accordance with 401.19. Acceptable methods for the correction of irregularities indicated by the check method used are given below.

Special Requirements for Surface Course

Construction Requirements

Before placing a surface course onto an intermediate course, a coat of tack must be applied to the intermediate layer.

Where the surface course has been damaged due to inadequate bonding, it must be removed and a tack coat applied before the surface placing is continued.

On projects where traffic is maintained, the longitudinal joints between adjacent lanes of surface course pavement must be completed within 24 hours. Where this time limit is exceeded, the joint should be inspected, and if the joint appears to be excessively rounded or displaced, necessary corrections should be made as provided in 401.17. This action should be recorded in the project records.

Traffic should not be permitted on a completed surface course until the mixture has cooled sufficiently to prevent glazing or the drawing of asphalt material to the surface of the pavement due to tire action.

Where the completed surface course is placed directly against an adjacent curb face, the surface course should be sealed along the gutter line. When sealing is required, the operation should be inspected and the use of an excessive quantity of asphalt material or sloppy application should not be permitted. Only the quantity of asphalt material necessary to fill the surface voids should be used. The material should be applied at a uniform rate, approximately 4 inches (100 mm) in width. The asphalt material used for the seal shall be asphalt cement. Because of the small quantity of material involved, the approval of the asphalt material to be used for this purpose may be based on field inspection, and the results of the inspection recorded on the Inspector’s Daily Report, with the material identified as to grade, manufacturer, and use.

Correction of Surface Course

The specifications require that irregularities and defects be corrected in a manner satisfactory to the Engineer. The following methods will produce satisfactory results when the work is properly performed by sufficiently skilled workers.

In general, heat may be applied to aid in the removal of surface course material only when the affected area will be covered with new material. When heat is applied, the adjacent material which will remain in place must be shielded from the heat to avoid permanent damage.

Where removal of defective material is required, removal limits should be defined by cutting or sawing to neat lines. After the defective material has been removed, the area and the edges should be given a uniform coating of tack coat material. The replacement material should then be placed and compacted to conform to the surface of the surrounding material.

Minor segregated areas in which there is insufficient fine aggregate at the surface can be corrected by a squeegee application of a commercial sealer containing asphalt material of the same type as was used in the mixture. An emulsion of the asphalt material along with added fine aggregate is also effective. Careful use of the squeegee is necessary to fill the surface voids without leaving a surplus of the sealer on the surface.

Where additional surface course mixture must be added to correct a low area in the surface, correction area limits should be defined by cutting or sawing to neat lines followed by removal of material as necessary to permit replacement at not less than 0.5 inch (12.5 mm) thickness. The surface of the area to be corrected and the face of the butt joint should be given a coating of tack coat material. The replacement mixture should then be placed and compacted as required to effect the needed correction.

Where material must be removed to correct high areas in the surface, satisfactory correction often can be accomplished by using a surface grinder or a cutter planer. Removal and replacement of the surface course and a portion of the underlying material may be necessary in extreme cases.

Method of Measurement (401.21)

Control of Quantity Placed

The specifications require placing of asphalt concrete on the basis of weight per unit of volume. The weight per unit volume (conversion factor tons/cubic yard) is established by the laboratory.

For a given course the required placement rate (RPRS) is calculated in tons per station. Every 500 feet (150 m), at the end of a full load the exact length of the section should be measured and a check should be made to ensure that the placement rate is within +5%.

Conversion Factor Established by the Laboratory

The unit weight of a mix can be obtained from the “BCJMF” screen in the TAS portion of CMS. You will need to know the JMF number of the mix to use the “BCJMF” screen; otherwise, conversion factor is obtained from Table 401.21. To establish the required placement rate, this conversion factor (unit weight per cubic yard) is multiplied by volume to the asphalt pavement per station.. Therefore, the placement rate, in tons per station is given by the following equations:

RPRS = [Volume of asphalt in cubic yards] X [Lab Conversion Factor (ton/yd³)]

= [Station length (100 Ft) X Lane Width (ft) X Mat Thickness (ft) ÷ 27

ft³/yd³] X C.F.

= tons/station

APR = [Material Used (Tons) ÷ (Test section length (Feet) ÷ 100)]

= tons/station

Where

RPRS is the required placement rate per station

APR is the actual placement rate per station

C.F. is the lab conversion factor (tons/yd³)

Example: Roller Capacity and Placement Rate

A contractor is using one three-wheel roller, one vibratory roller with 66-inch drums (both vibrating) and one Type 2 pneumatic tire roller to compact a mat 3 inch thick using material with Lab conversion factor of 2.0 tons per cubic yard.

From Table 401.13-1 the following is the capacity of the rollers the contractor will use:

· Three wheel = 700 sq yd/hr

· Vibratory roller = 2 drums x 66 in x (15 sq yd/in of width) = 1980 sq yd/ hr

· Type II Pneumatic Roller = 700 sq yd/hr

· Maximum roller capacity = 700 + 1980 + 700 = 3380 square yards/hour

3380 yd²/hr X (3 in ÷ 36 yd³/in³) = 469.44 yd³/hr.

469.44 yd³ X 2.0 tons/Yd³ = 281.66 tons per hour maximum placement rate.

Determining the Required Placing Rate per Station (RPRS)

A contractor is placing a 5 inch uniform mat of asphalt concrete pavement whose Lab conversion factor is 2.0 tons/cubic yard. The required placing rate (RPRS) in tons of material per station for a 12 ft wide mat is:

RPRS = [Volume of asphalt in cubic yards] x [Lab Conversion Factor]

= [100 ft X 12 ft X (5 in ÷ 12 in/ft) ÷ 27 ft³/ yd³] X 2.0 tons/yd³

= 37.04 tons/station

This rate should be rounded off to two digits after the decimal for control purposes.

In order to construct courses for uniform thickness in new full-depth or base-widening construction, the Contractor is required to maintain the calculated rate of placing within a specified tolerance of plus or minus 5 percent. The Inspector must check this placement rate , using the plant ticket forms which must accompany each load of material, and the area covered by a given number of loads. The area to be used for the check should not be greater than 500 feet (150 m) in length and should be measured from the start of a full load of asphalt concrete to the end of a full load. The results of these checks should be recorded on Form CA-FP-4, BITUMINOUS CONCRETE INSPECTION or the Inspector’s Daily Report. If Form CA-FP-4, BITUMINOUS CONCRETE INSPECTION is not being used or is not available, a suggested format for the check is:

Location of Test Section
Plan Thickness
Required Placement Rate (A)
Length of Test Section
Width of Test Section
Actual Placement Rate (B)
Specification Tolerances (A ± 5%) = B ÷ A

When variations greater than plus or minus 5 percent of the required rate are detected, the inspector should require the Contractor to adjust the paver accordingly, and immediately check the rate at the new setting.

Depending on the nature of the material being placed and quality of the placing operation, one to four placement rate checks per day normally will represent the material placed with a given paver. When the work involves a series of small areas, the use of partial loads at each location makes the weight check impractical. In such cases, the inspector should determine that at least plan thickness is being obtained.

The placing of asphalt concrete should be closely controlled and kept as near as possible at the specified rate. Even for a well-controlled operation, however, both positive and negative variations will occur and are to be expected. The Contractor should not place the material at a rate greater than that required since this would result in an overrun of plan quantity for which the Contractor would not be paid. As stated in 401.21 Method of Measurement, the pay quantity is limited to the total weight of the item placed, converted to cubic yards (cubic meters), with no payment made for the quantity of material placed which exceeds that calculated from plan lines and dimensions.

Basis of Payment (401.22)

Acceptance Sampling

With the exception of 446 samples, remaining asphalt concrete is sampled and tested by the contractor at the asphalt plant. Contractor tests are used for pay if they are verified by District testing. 446 samples are located by the Engineer, taken by the contractor, and tested by the District. See 403.06 for sampling detail. See the specific asphalt concrete item in this manual for additional sampling information.

Cutting Pavement Samples

Cut pavement samples are obtained when additional tests are needed on the finished asphalt concrete pavement.

The location of a cut pavement sample is selected in a random manner, as specified in Supplemental 1035. The cut pavement sample should be 12 inches × 12 inches (305 mm × 305 mm). If the cut pavement sample breaks while it is being removed from the pavement, take care to obtain all of the pieces.

After a cut pavement sample is obtained, it should be packaged and identified in accordance with current District or Laboratory policy. The sample should be shipped to the District lab as soon as possible. Most District labs are not able to test cut pavement samples, so the District will forward the sample to the Laboratory for testing.

Cut pavement samples are usually tested to determine the gradation and binder content of the asphalt concrete mix.

Quantities for Payment

Summarizing Quantities

A plant ticket form approved by the Laboratory must accompany each load of asphalt concrete delivered to the project and accepted for placement. When the load is accepted at the paving site, the paving inspector records the placement location and validates the ticket in the space provided.

A daily summary by item and location should be made of the weight of asphalt concrete placed.

When the placement of asphalt concrete items has been completed, a final summary of the weight placed must be made for use in the determination of the pay quantity for each item. The final summary should be broken down by separate pavement areas. In general, separate pavement areas are defined as separate contract parts, separate participation codes, physically separate roadways, and pavement areas having differing design sections. The total weight summarized is converted to cubic yards (cubic meters) using the applicable conversion factor.

Converting to Cubic Yards (Cubic Meters)

After the total weight of material used in a pavement section has been determined, it must be converted to cubic yards (cubic meters) using the applicable conversion factor established in accordance with 401.21. In 401.21, the Laboratory establishes the conversion factor when a mix design is available for the project. The conversion factor of a mix can be obtained from the “BCJMF” screen in the TAS portion of CMS. You will need to know the JMF number of the mix to use the “BCJMF” screen. If no mix design is available, the conversion factor is determined using table in 401.21. Depending on the conversion factor used, the total weight of material used in a pavement section can be converted to cubic yards (cubic meters) as follows:

[TW ÷ CF]

where:

TW = total weight of pavement area (tons)

CF = conversion factor (tons/yd³) or (tons/m³)

This volume should be rounded off to the nearest cubic yard (cubic meter).

Pay Quantity - New Construction

Where asphalt concrete is placed on a subgrade, subbase, or base constructed under the contract, the plan depth is uniform and the pay quantity is the quantity placed providing it does not exceed the quantity calculated using plan lines and dimensions. Quantities placed in excess of the plan quantity are not eligible for payment.

However, where a pavement consists of more than one item for example (301, 448 type II and 448 Type I), an excess in the quantity of one item may be transferred to offset a deficiency in the quantity of another item. Payment for the transferred quantity should be made at the lower unit bid price. Such transfer of quantities should not be made from the summary for one separate pavement section to another. Separate pavement sections are defined as separate contract parts, separate participation codes, physically separate roadways, and pavement areas having differing design sections.

No transfer should be made to offset a deficiency in the quantity of a surface course item.

Pay Quantity - Minor Rehabilitation

Where one to two courses of asphalt concrete is placed on an existing pavement for the correction of the profile and cross section, the depth is variable and the pay quantity is the quantity placed as directed by the Engineer in accordance with the intent of the plans. Placement rate checks, as described in Section 401.21, should be used to verify that the Contractor is meeting the intent of the plans.

Pay Quantity - Major Rehabilitation

Where multiple courses (three or more) of asphalt concrete are placed as part of a major rehabilitation of a pavement section, part of the asphalt concrete will be used for the correction of the profile and cross section of the rehabilitated pavement, as described above, and the rest of the asphalt concrete will be placed at a uniform depth, as described in Section 401.21 Pay Quantity – New Construction.

For the course(s) used to correct the profile and cross section, the pay quantity is the quantity placed as directed by the Engineer in accordance with the intent of the plans. Once the Engineer has determined the profile and cross section has been corrected, the rest of the courses should have a uniform depth and the pay quantity is the quantity placed providing it does not exceed the quantity calculated using plan lines and dimensions, in accordance with Section 401.21 Pay Quantity – New Construction.

Documentation Requirements - 401 Asphalt Concrete Pavements-General

This section outlines mix designs (401.02), mixing plants (401.05), hauling, and placement of material.

1. Observe trucks hauling material

a. Check for secured waterproof cover

b. Insulate truck beds for temperatures below 50° F (10° C) and/or if the haul exceeds 20 miles (32 km)

2. Check roller capacities as outlined in 401.13

3. Compaction requirements as per 401.16

4. Periodically check field production quantity compliance

5. Document on CA-FP-2 through 4

407 Tack Coat

Description (407.01)

The tack coat is an application of liquid asphalt material on an existing pavement surface, used as an aid in bonding a new asphalt concrete course to the existing pavement surface. Proper application of tack coat is a key factor in producing a quality asphalt paving project. Tack coat promotes bond between asphalt layers to achieve a maximum strength of the pavement structure. Proper tack coat application prevents separation or movement of asphalt layers and provides a long-lasting quality pavement.

Materials (407.02)

Tack coat used should be RS-1, SS-1, SS-1h, CRS-1, CSS-1 or CSS-1h and conforms to the application requirements of 702.

When paving over a concrete pavement the tack coat used should be rubberized asphalt emulsion conforming to 702.13.

Emulsions are classified as rapid setting (RS or CRS), Medium setting (MS o CMS), or slow setting (SS or CSS). The letter “C” in front of an emulsion type (CRS, CMS, Or CSS), denotes a cationic (positively charged) emulsion. If the emulsion type is followed by an “h” (SS-1h) it means the emulsion was made from harder base asphalt cement.

Equipment (407.03)

The inspection and approval of asphalt distributors used to apply tack coat material are governed by the ability to fulfill 407.06 and 407.03.

Mechanical sweepers and other related hand equipment may be of any type that will accomplish the required results.

Weather Limitations (407.04)

The tack coat should not be applied when the surface temperature of the existing pavement is below the minimum placement temperature for the pavement course to be placed. The minimum placement temperatures for pavement courses are specified in 401.06. The surface temperature is to be recorded on the Inspector’s Daily Report.

Emulsified tack coat could be applied to a damp pavement; however, more time will be needed for the emulsified asphalt to set. A change in color from brown to black is a visual indicator when the tack is set.

Damp surfaces will not have visible flowing water on the surface.

Preparation of Surface (407.05)

The pavement surface should be free of any material accumulations that might hinder the bond of the tack to the pavement. Excessive use of tack coat should never be a substitute for proper cleaning of pavement. Excessive tack coat will act as lubricant creating a slippage plane between pavement layers.. Material accumulations to be removed include dust, loose aggregate, soil, leaves, and pieces or lumps of other foreign material deposited on the surface. Cleaning may require brooming, handscraping, and perhaps power blading of heavy accumulations. Special attention should be given to the edges to assure proper coverage of the full width intended.

Application of Asphalt Material (407.06)

A field review of the existing pavement surface should be made soon after the award of contract in order to determine tack coat requirements. Requirements should be determined and transmitted promptly to the Contractor to facilitate job planning. Guides for determining quantity of tack coat needed are given under the following types of resurfacing:

1. Asphalt Concrete Placed on Portland cement or brick Concrete - A light tack coat application, 0.05 to 0.10 gallons per square yard (0.23 to 0.45 liters per square meter), is always required on existing Portland cement concrete pavements. Rubberized emulsion meeting specification 702.13 shall be used.

2. Asphalt Concrete Placed on Asphalt Concrete - Normally the existing asphalt concrete surface will be somewhat dry from weathering and a moderate application, 0.10 gallons per square yard (0.45 liters per square meter) or less, should be made. For thin, less than 1 inch (25 mm) single course resurfacing, a uniform light coverage over the entire surface is of particular importance.

Protection and Control of Traffic

When the contract requires traffic to be maintained, tack coat application should not be allowed to start until the provisions of the traffic maintenance item have been met. Alternate movement of one-way traffic must be in place before the distributor is brought into the starting position. Give special attention to the Contractor’s operation relative to traffic movement. Every reasonable effort should be made to keep “pick up” of the asphalt material, prior to paving, to a minimum. This may involve tacking in sections and allowing time for curing.

Application of Asphalt Material

Only asphalt material meeting the requirements of 407.02 can be used. Loads of asphalt material delivered to the project should carry evidence of approval as defined under section 106. This evidence of approval and the material weight tickets must be validated at the paving site.

For large areas, the application rate is determined by the application of a given quantity of an asphalt material over a known area. The rate is calculated using the gallons (liters) indicated by the volume indicating device on the distributor, the known length of the distributor run, and the measured width covered. The distributor may be approved only when the measured application rate is within plus or minus 10 percent of the required rate. The application rate for small areas, where volume measurement is not practical, may be judged visually.

The elevation of spray bar should be maintained at a sufficient height and the nozzles should be angled 15º to 30º from the axis of the spray bar, to produce fully developed fan of bituminous material that will overlap with the fan from the adjacent nozzle.

The operation of the distributor is judged by visual observation. The quantity of material flowing from each nozzle should appear to be uniform. The angle of each "fan" of material with the spray bar should appear to be the same; the particular angle is specified by the manufacturer. The material should be applied uniformly across the width of the spray bar with no visible streaks and with no apparent variations in thickness from the beginning to the end of the run.

The results of the foregoing observations and check tests are recorded for each distributor proposed for use together with a means of identification (license plate or equipment number) and indication of approval or non approval. This information is entered in the project record as a supplement to the Inspector's Daily Report.

The asphalt material should be sprayed uniformly on the pavement surface. If streaking occurs, the Contractor must adjust the distributor. Streaking is caused by faulty distributor adjustment or operation, resulting in the asphalt material being placed in ridges. Contrary to popular belief, these ridges will not “flow” together. The result is insufficient asphalt material between the ridges to bond the new asphalt paving course to the existing pavement surface.

Example of good application

Example of bad application

Application of Cover Aggregate (407.07)

To maintain a safe construction zone, traffic should not be allowed over tacked surfaces at all times unless aggregate cover is used to provide friction and prevent tack pick-up. Cover aggregate is required to be sufficiently dry to permit adhesion of liquid asphalt. When the cover aggregate is placed on an asphalt emulsion tack coat, the aggregate may be moist, but not to the extent that free water drains from the truck bed.

For all types of asphalt materials, the cover aggregate should be placed as close behind the distributor as is practical.

The Contractor is required to apply only the quantity of cover aggregate needed to prevent “pick up” by traffic. A typical rate for applying cover aggregate is 4 to 8 lbs/yd².

Quantities for Payment (407.08)

Determine gallons (liters) from weigh tickets or weighed partial loads. For weights or volumes that are questionable or unknown a volume-measuring device is required before accepting the material. Cover aggregate is included in the bid price for the tack coat.

Documentation Requirements - 407 Tack Coat

1. Atmospheric temperature

2. Temperature of material

3. Convert weight to gallons as per current test lab policy. CA-FP-6 form will be a useful aid in this process.

4. State if all the load is used; if not, be sure to get a weigh back

5. Meter reading from the back of distributor will not be acceptable

6. Use cover aggregate when tack will be exposed to traffic. Collect load slips from cover aggregate (This is not a separate pay item.)

408 Prime Coat

Description (408.01)

Construction requirements for prime coats are included in 408. An asphalt material having low viscosity is required for a prime coat. This material is intended to penetrate a prepared granular surface prior to the placement of an asphalt concrete mixture. The purpose is to bind the granular particles together for some depth below the surface.

Asphalt Material (408.02)

Be sure the material used meets 408.02.

Cover Aggregate (408.03)

Be sure cover aggregate meets the requirements of 408.03.

Weather and Moisture Limitations (408.04)

When there is sufficient moisture present in the aggregate to impede the penetration of the asphalt material, or when the atmospheric temperature is below the minimum specified in 408.04, application of the prime coat should not be permitted.

Equipment (408.05)

The inspection and approval of the asphalt distributors used to apply the prime coat material is covered in sections 407.03 and 407.06. The spreading of the cover aggregate, when required, can be accomplished by any approved method, depending upon the specific job conditions. When sweeping is required, the brooms approved for use should produce a uniform surface without causing damage.

Preparation of Surface (408.06)

The surface to be primed should meet all requirements for the particular specification item. Irregularities in excess of specified tolerances must be repaired prior to priming.

Application of Asphalt Material (408.07)

The specified application rate for the asphalt material is an estimated rate suitable for average conditions. Open textured surfaces may permit an increase, while dense surfaces may require a reduction in the estimated rate. The application rate should be such that the prime will be absorbed by the material within 24 hours.

Proper application of the asphalt material is covered in 407.06 and 408.07.

Only asphalt material meeting the requirements of 408.02 may be used. Loads of asphalt material delivered to the project should carry evidence of approval as defined in section 106. This evidence of approval and the material weight tickets are to be validated at the paving site before the material is used.

Quantities for Payment (408.09)

Determine gallons (liters) from weigh tickets or weighed partial loads. For weights or volumes that are questionable or unknown, a volume-measuring device is required before accepting the material. Cover aggregate is included in the bid price for the tack coat.

Documentation Requirements - 408 Prime Coat

1. Atmospheric temperature

2. Temperature of material

3. Convert weight to gallons as per current test lab policy. CA-FP-6 form will be a useful aid in this process.

4. State if all the load is used; if not, be sure to get a weigh back

5. Meter reading from the back of distributor will not be acceptable

Use cover aggregate when tack will be exposed to traffic. Collect load slips from cover aggregate (This is not a separate pay item.)

409 Sawing And Sealing Asphalt Concrete Pavement Joints

Materials (409.02)

Be sure approved materials are used per 409.02 requirements.

Construction Details (409.03)

Check that the following operations are proceeding properly per 409.03:

1. Intermediate course is saw cut if surface is not placed within 5 days.

2. Saw cut the surface within 48 hours.

3. Alignment of saw cuts over joints.

4. Check saw cut dimensions.

5. Proper cleaning of the cut.

6. Length of cut.

7. Keep clean until sealing.

8. Proper sealant heating according to manufacturer’s instruction.

9. Check for backer rod placement, sealant thickness, and uniform placement.

Documentation requirements - 409 Sawing and Sealing Asphalt Pavement Joints

1. Saw cut surface course over joints within 48 hours of placement

2. Review method for locating joints

3. Saw cut must extend 1/8 inch (.32 cm) into the intermediate course if the intermediate course is not covered within 5 days

4. Clean and fill sawed joint with material as per 705.04

5. Document measurement on CA-D-2

410 Traffic Compacted Surface (04/24/06)

Specification Changes

No specification changes to this section.

Because of the simplicity this item of work, no detailed explanation of the item is required in this manual.

Documentation Requirements - 410 Traffic Compacted Surface

1. Materials

2. Subgrade condition.

3. Document location where material was used on the ticket.

4. State if all load was used; if not, be sure to get a weigh back

5. Blading operation.

6. Maintenance.

7. Weigh tickets should be totaled with an initialed and dated tape attached.

a. Convert to cubic yards as per 410.06 of the C&MS.

8. Pay and measure according to 410.06 and 410.07.

9. Document on the CA-EW-12 and CA-D

a. Do not duplicate the information on these forms unless necessary.

411 Stabilized Crushed Aggregate

Specification Changes

No changes made to specification.

Because of the simplicity this item of work, no detailed explanation of the item is required in this manual.

Documentation Requirements - 411 Stabilized Crushed Aggregate

1. Materials.

2. Document location of where material was placed and lift thickness.

3. Roller weights.

4. Lift thickness.

5. Roller passes.

6. Use a rubber tire roller for the final compaction.

7. Perform the compaction tests according to S-1015.

8. Weigh tickets should be totaled with an initialed and dated tape attached. Convert to cubic yards as per 411.04 of the C&MS.

9. Pay and measure according to 411.04 and 411.05

10. Document on the CA-EW-12 and CA-D

a. Do not duplicate the information on these forms unless necessary.

421 Microsurfacing

Materials (421.02)

Validate that the latex and CSS-1H emulsion used meets requirements. Collect the manufacturer’s certificate of analysis and statement of compliance for each load.

Proportioning (421.03)

Validate the JMF approval.

Weather Limitations (421.04)

Allow the microsurfacing to be placed if:

1. minimum surface temperature is 40° F (5° C).

2. no air temperature below 32° F (0° C) is forecast within 24 hours of placement.

3. minimum surface temperature is 50° F (10° C) between September 30 and May 1.

Mixing Equipment (421.05)

Validate the contractor is using proper equipment.

Equipment Calibration (421.06)

Witness calibration of the mixing equipment before start or for any design change. Obtain documentation of individual materials calibrations from the equipment calibrator.

Spreading Equipment (421.07)

Validate the contractor is using proper equipment and that it moves and spreads the material uniformly without excess loss in isolated areas.

Surface Preparation (421.08)

Be sure the surface is clean before application. Check for proper tack application. Be sure raised pavement markers are removed.

Test Strip (421.09)

Be sure a test strip is constructed in the same time of day as construction is expected. Review the test strip after 24 hours to determine acceptability. The test strip may be only waived according to 421.09.

Application (421.10)

Check for the following construction requirements:

1. no skips, lumps, or tears in the material placed

2. complete coverage

3. no unmixed aggregate

4. no excess crown on rut fills

5. restore the crown of the designed pavement cross section

6. apply leveling at 14 pounds per square yard (7.6 kg/m2)

7. apply a surface on a microsurfacing course at 16 lbs per sq yard (8.7 kg.m2)

8. apply a surface not on a microsurfacing course at 18 lbs per sq yard (9.8 kg.m2)

9. neat seams at 1 to 6 inches where passes meet

10. maintain straight edge lines and other lines

11. check for cure before release of traffic but that it cures within 1 hour.

12. stop placement if excessive streaking or other problems develop

13. Use a rubber tire roller if the material is not under traffic within 48 hours. The roller tire should meet 401.13 and tire pressure should be 40 to 60 psi (275 to 400 kPa).

Acceptance (421.11)

Accept microsurfacing based on the Engineers summary of quantities for each day provided the proportion of binder to dry aggregate is maintained within 2 gallons per ton (8.5 L/metric ton).

Documentation Requirements - 421 Microsurfacing

1. Check for certificate of analysis and compliance from the manufacturer of the binder

2. Surface temperature must be 40° F (4° C) or above and the atmospheric temperature must be 32° F (0° C) for 24 hours

3. Surface temperature must be above 50° F (10° C) if placed between September 30 and May 1

4. Clean surface and apply tack coat

5. Equipment and application methods are outlined in 421.07 and 421.10

6. Construct test strip

7. Document on CA-D-3A

422 Chip Seal With Polymer Binder

Description (422.01)

The chip seal consists of an application of polymer modified asphalt emulsion covered by an application of aggregate. It is applied as a single or double chip seal for use as a surface course on all types of pavements and on paved berms.

As the name implies, the purpose of the chip seal is to seal and protect the underlying course from weathering and from wear by traffic. A film of asphalt material provides this protection. The purpose of the cover aggregate is to protect the film from traffic and provide a skid-resistant surface. When applied on berms, the cover aggregate provides delineation of the traffic lanes from the berms by a change in surface color and texture.

A Chip Seal Operation

Chip Seal Prior to Rolling

Equipment (422.03)

The following equipment should be checked and approved before it is used on chip seal construction.

Asphalt Distributor Applies the Polymer Binder

Distributors

The inspector should make a general inspection of the distributor to become familiar with the particular equipment and to detect any variance from the specifications that can be observed. In particular, the inspector should have the Contractor demonstrate the use of the required volume measuring device, thermometer, and application controls. Work should not be permitted to start if this equipment is unsatisfactory. The equipment for polymer binder distribution should conforming to 407.03, except ensure that it has a computerized rate control that automatically adjusts the polymer binder pump to the unit ground speed. Use appropriate spray nozzles for the material and rate specified. In addition, the approval of the distributor is based on observation of the operation and check measurements of the actual application rate, performed as described in the following paragraphs.

For large areas, the application rate is determined by the application of a given quantity of asphalt material over a known area. The rate is calculated using the gallons (liters) indicated by the volume-indicating device on the distributor, the known length of the distributor run, and the measured width covered. The distributor may be approved only when the measured application rate is within plus or minus 6 percent of required rate. The application rate for small areas, where volume measurement is not practical, may be judged visually.

While some visible defects in application such as streaking or ridging will not seriously affect performance of prime or tack coats, however, they cannot be tolerated when applying polymer binder for chip seal work. This means the inspector must be more particular where chip seals are involved and must approve or prohibit use of a particular distributor accordingly.

The results of the foregoing observations and check tests are recorded for each distributor proposed for use together with a means of identification (license plate or equipment number) and indication of approval or non-approval. This information is entered in the project record as a supplement to the Inspector's Daily Report.

After the initial inspection, continued approved status of a given distributor depends on continued satisfactory results determined visually or by additional checks when deemed advisable.

Rollers

Only Type II pneumatic rollers conforming to 401.13 are permitted for embedding. The contractor should use a minimum of three rollers.

Type II Pneumatic Tire Rollers Used to Embedding the Aggregate

Aggregate Spreaders

The aggregate spreader must be self propelled with a variable width aggregate hopper and shall conform to specification 422.03. The spreader must produce a uniform application of aggregate without gaps or ridges at the rate specified.

Aggregate Spreader Spreads the Aggregate on top of the Polymer Asphalt Binder

Brooms

Rotary brooms are also used for the initial surface preparation to sweep the roadway prior to the application of the polymer binder. A rotary broom or sweeper is required to sweep excess cover aggregate from the completed surface without dislodging the embedded aggregate.

Rotary Brooms

Weather and Moisture Limitations (422.04)

For chip seals, the weather limitations are specified in 422.04. This section requires a pavement and atmospheric temperature of 60º F (16º C) or above. Work should not begin if there are forcasted temperatures below 50º (10º C) within 24 hours from the start of work. Do not place the chip seal if the existing pavement temperature is 140 F (60 C) or above. This work is not to be done before May 1 or after September 1.

Preparation of the Surface (422.06)

Before a chip seal is applied on an existing surface, all irregularities in excess of specified tolerances should be corrected and all material accumulations that would interfere with the adhesion of the asphalt material should be removed. Objectionable material includes dust, loose aggregate, soil, leaves, and pieces or lumps of other foreign material. Proper cleaning of the surface requires brooming and may necessitate hand scraping and power blading of heavy accumulations. Special attention should be given to the edges to assure proper coverage of the width intended.

Application of Asphalt Material (422.07)

Only asphalt material meeting the requirements of 702.16, Type A is permitted for use. Loads of asphalt material delivered to the project should carry evidence of approval. This evidence of approval and the material weight tickets must be validated at the paving site before the material is incorporated into the work.

A uniform application both in the transverse and in the longitudinal direction is important, particularly in chip seal work. Continued application should not be permitted when visible defects occur. Where it is demonstrated that distributor results are erratic, discontinue use of the equipment until the equipment defects are corrected.

With all other conditions being equal, the application rate of asphalt material depends on the average size of the cover aggregate particles. In a good chip seal, the average size particle will be embedded for approximately half its thickness after thorough seating by rolling. When the application rate is too heavy, the particles may become totally embedded, resulting in a flushed or bleeding surface. When the application rate is too light, the particles may not be held with sufficient firmness to resist dislodging forces of traffic, and a loss of cover aggregate will result.

The application rate required to produce proper embedment for a given particle size also may depend upon the porosity, absorption, and firmness of the surface to be sealed. The rate specified in the contract may require adjustment depending upon the actual nature of the surface. Considerable judgment is required to determine the proper application rate and to avoid undesirable effects of bleeding or raveling.

In order to check the specified application rate, the existing surface conditions should be observed and an application of asphalt material made over a small area. After application of the cover aggregate, the area should be rolled thoroughly to assure maximum embedment of the aggregate particles. The amount of embedment of an average size particle should be observed at several locations. Adjustments should be made in the rate of application of the asphalt material based upon the observed results and the following facts:

1. Little additional embedment will occur under traffic on a hard surface, while considerable additional embedment may be expected to occur on a soft surface. A hard asphalt surface may become soft as the temperature increases, however, and allowances must be made when this condition exists.

2. On a porous surface, application temperature of the asphalt material should be held to the lower side of the specified range 150 ºF (65 ºC) to keep penetration to a minimum.

3. For a given application rate, flat-shaped particles require less asphalt material than particles having a rounded or cubical shape.

4. Under rolling and traffic, aggregate particles will be forced into a flat orientation (greatest dimension parallel to the pavement surface).

Application of Cover Aggregate (422.08)

Only aggregate that has been approved is permitted for use. Validate the weight tickets when the material is received at the paving site.

The application of cover aggregate must follow the application of asphalt material closely. For this reason, the length of the distributor runs should be regulated to permit the spreader operation to place the aggregate immediately behind the distributor.

The aggregate must be sufficiently free from dust and moisture to permit immediate adhesion of the asphalt material.

Cover aggregate should be applied in one layer of aggregate particles. The rate of application is dependent only on the characteristics of the aggregate. It can be determined in advance by spreading a single dense layer of the actual aggregate to be used on the surface of a given area, and weighing the quantity used. This quantity then is increased by 20 percent and the application rate calculated in pounds per square yard (kilograms per square meter). After this rate of application has been established, it should govern the amount of aggregate used on the remainder of the work.

Application of cover aggregate in excess of requirements for complete coverage should be avoided. When an excess of material is applied, the particles tend to interlock, interfering with orientation and embedment under the rolling.

Construction Operation (422.09)

Rolling

Rolling of the chip seal cover aggregate is required to begin immediately behind the aggregate spreader. This is to assure that the aggregate particles will be embedded in the asphalt emulsion, worked into a stable position before the emulsion breaks, and will adhere to the cured asphalt emulsion.

Specifications require a minimum of two complete roller coverages of the cover aggregate. Eachcoverage consists of two one-way trips or passes of the roller over a given area. While making these coverages, the speed of the roller must be slow enough, not greater than 5 miles per hour (8 km/h), to avoid displacing or dislodging the aggregate particles from the asphalt.

Protection of Completed Work

The completed chip seal construction should be protected from both construction and public traffic until the asphalt material has cured sufficiently to prevent dislodging of the embedded aggregate. Under normal conditions, a new chip seal will not be harmed when subjected to immediate traffic if the speed of the traffic is kept low, no more than 25 miles per hour (40 km/h). In the event of rain on a fresh chip seal, however, the curing of the asphalt emulsion may be delayed by the presence of water, and traffic should be kept off the pavement until the curing has been completed. The excess cover aggregate must be removed from the pavement by light brooming within 4 hours. This should be done as soon as practical after the work has been completed, but not before sufficient curing has taken place to prevent dislodging the embedded aggregate particles.

Acceptance (422.11)

Acceptance of the final product depends on daily inspection of the six items listed in 422.11 and final inspection after 25 – 35 days for the defects listed in 422.11.

Deficiencies in chip seal construction often do not show up until the surface has been under traffic for a period of time. It is necessary, therefore, to learn to detect practices during construction which will result in inferior work. An effective way to develop this skill is to observe previous chip seal work, noting deficiencies and determining the probable cause. Following are listed some common deficiencies which occur in chip seal construction and their probable causes:

Streaking or obvious surface patterns

Streaking is caused by faulty distributor adjustment or operation, resulting in the asphalt being placed in ridges. Contrary to popular belief, these ridges will not "flow" together, particularly when the cover aggregate is applied immediately after the application of asphalt material as it should be. The result is insufficient asphalt material between the ridges to hold the aggregate in place and the aggregate soon will be whipped off by traffic. This leaves only the aggregate, which is well bonded in the ridges and produces a streaked appearance.

Loss of Cover Aggregate

This is a serious form of chip seal failure because of the traffic hazard created by the exposure of the slippery film of asphalt material and flying aggregate particles. It may be caused by one or more of the following:

1. Too light an application of the asphalt material

2. Penetration of the asphalt material into the underlying surface

3. Use of an improper grade of asphalt material for existing conditions

4. Delay in spreading the aggregate on the asphalt emulsion

5. Excess aggregate application

6. Lack of adequate rolling

7. Use of wet or dirty aggregate

8. Opening the roadway to traffic before adequate curing has taken place

Bleeding

Bleeding is defined as a flushing of asphalt material to the surface, completely or almost completely submerging the cover aggregate. Continuous bleeding simply is the result of too high a rate of application. Spotty bleeding usually is the result of variations in the surface of the existing pavement. Bleeding at connections between distributor loads is the result of an overlap of the previous run.

Bleeding or Flushing of a Chip Seal

Documentation Requirements - 422 Chip Seal with Polymer Binder

Contractor should provide a Quality Control report with information as dictated in section 422.10 of the C&MS.

Inspectors should determine in advance the aggregate application rate calculated in pounds per square yard (kilograms per square meter).

Inspectors must measure and calculate the area in square yards of single or double chip seal with polymer binder courses places and accepted.

423 Crack Sealing, Hot Applied

Materials (423.02)

Validate material type: do not accept Type 1 material on a project that is not prior approved in the TE 24 system. Check approval of other types per SS 925. Verify backer rod is on approved list.

Equipment (423.03)

Verify the equipment to be used is correct for the sealant type and that it meets the other requirements listed in 423.03.

Weather Limitations (423.04)

Surface must be dry (no visible moisture of any kind) and at least 45° F (7° C).

Preparation (423.05)

Be sure cracks to be sealed are properly located. Check for proper routing or sealing. When sawing, be sure sandblasting is performed. Use backer rod as directed in 423.05. Approve the method used by the contractor to clean cracks.

Mixing Type II and Type III (423.06)

Determine the proper proportion of fiber and binder to blend by using weigh tickets. Check for thorough mixing. Check sealant temperature against manufacturer recommendation. Be sure Type III does not exceed 295 F (146 C) at any time.

Application of Sealant (423.07)

Be sure the operation proceeds properly as specified. Fill cracks within 250 feet (76 m) of the cleaning operation. Determine types of cracks to seal per 423.07. For Type I and IV sealant, check for proper use of a squeegee per 423.07. Sealant should generally not be more than 2 inches (50mm) wide (use discretion).

For type II and Type III sealant, the width of the band should be 2 to 4 inches but never over 4 inches. Do not accept the work if the thickness of the sealant is be more than 3/16 inches (5mm).

Opening to Traffic (423.08)

Do not allow traffic on fresh sealant unless it is covered with an anti-tracking material.

Documentation requirements - 423 Crack Sealing Hot Applied

1. Materials as per 423.02

2. Document type of sealant used (type I, type II, type III, type IV) and mixing methods

3. Pavement is to be dry and the temperatures above 45° F (7° C)

4. Open to traffic after there is no possibility of tracking

5. Determine weight of sealant for pay

424 Fine Graded Polymer Asphalt Concrete

General

This specification is intended to be used for pavement preventive maintenance but may have other applications as well. The specification includes two mixture compositions, Type A and Type B. Both mixtures are required to use a polymer binder.

Composition 424.02

The Type A material is a very fine graded mix composed of primarily natural sand and contains a very high polymer binder content (8.5 %). This is a recipe mix. It is designed to give a very long life but generally is not for high truck situations. A Type A mix is normally specified as a 5/8 inch (16 mm) mat thickness.

The Type B material is a fine graded mix composed of more angular materials and contains less binder content than the Type A mix (minimum of 6.4 %). This mix is designed by the Marshall Method for light, medium or heavy traffic. The Type B mix is designed to be more rut resistant than Type A but still contains a polymer binder for durability and ease of maintenance. The Type B mix can be placed on medium and high volume roads, including most interstate applications. A Type B mix is normally specified as a ¾ inch to 1 inch (19 to 25 mm) mat thickness.

Item 424 (Type A and Type B) Mix Compositions

Equipment

The equipment requirements of 401 apply to this work.

Materials (424.03)

Both types of mixtures under this specification are to use a polymer binder. Either a PG 76-22M asphalt binder or a PG 64-22 asphalt binder modified by the addition of 5.0 + 0.3 % styrene butadiene rubber (SBR) can be used.

The use of reclaimed asphalt pavement is not permitted by this specification.

Fine aggregate for use in this specification is required to have at least 50% silicon dioxide by weight. This special requirement assures proper skid resistance for both mix types.

Coarse aggregate used in the Type B mix is required to have 10 % two-faced crushed aggregate by weight for medium traffic applications and 100 % two-faced crushed aggregate for heavy traffic applications.

Mixing (424.04)

When these mixtures are discharged from the plant, the mix temperature must be between 335º F and 370º F (168º C to 188º C).

Mix Texture for Type A and Type B, Item 424

Weather Limitations (424.05)

The placement of either the Type A or B material is limited in that the existing pavement temperature and the ambient air temperature must be 60º F (16º C).

Acceptance (424.08)

The Type A mixtures are to be accepted using Item 301 procedures (see Item 403) and Type 2 materials are to be accepted according to Item 448 procedures.

Documentation Requirements - 424 Fine Graded Polymer Asphalt Concrete

1. State condition of base (example: primed 304, clean and dry concrete, etc.)

2. Write location on tickets where material is placed

3. Mark on ticket time unloaded

4. Obtain temperature of the mix at project site and place this information on ticket of load checked. This should be done a minimum of four times daily or any time temperature is in question.

5. State kind of rolling equipment and maximum tons per hour they are allowed to cover. See Example Roller Capacity and Placement Rate

6. Calculate and document the required placement rate (Tons/Station)

7. Document on form CA-FP-4

8. Lift thickness if required

9. Tickets should be totaled with initialed and dated tape attached

442 Superpave Asphalt Concrete

Description (442.01)

This item is a mix design and quality control specification. Generally, inspection requirements of section 401 apply. The main item of interest in the 442 specification is whether material is accepted by 448 or 446 specifications.

Acceptance Sampling and Testing (442.07)

Superpave items are accepted per 448 or 446 requirements, as specified. See those sections as needed.

Documentation Requirements - 442 SuperPave Asphalt Concrete

1. Sign tickets as receiving agent when possible

2. Document station where material is placed when possible

3. Mark on ticket time unloaded when possible, samples taken at plant.

4. Obtain temperature of mix at project site and place on ticket of load checked

5. Fill out form CA-FP-4

6. Lift thickness if required

7. Document quantities in specific areas

8. Place a statement in daily diary as to type and quantity of rollers. Roller capacity should be checked daily and anytime there is a change in type or size of rollers as per section 401.3-1 of the C&MS

9. Comply with current test lab policy for sampling each item

a. 446 - A lot is one day’s production. 10 cores are taken randomly per lot and forwarded to test lab with location and data sheet. (403.06-A) Form CA-FP-5, or TE-217

b. 448 - Tested and accepted by 3,000-ton lots. One test taken randomly every 750 tons (403.06-A). Samples taken at the plant, form CA-FP-2

446 Asphalt Concrete

Description (446.01)

This item of work consists of constructing a surface or intermediate course of asphalt concrete mix. The requirements of 401 for spreading and compacting the mix and the 441or 442 requirements of (mix design and quality control) apply, except as modified by the 446 specification.

For this item, 446 core samples are located by the Engineer utilizing form TE-217, taken by the contractor, and tested by the District.

The contractor must provide an approved Field Quality Control Supervisor (FQCS) as per 403.03, routinely and usually present at the paving site during placement of asphalt concrete pavement.

Density Acceptance (446.05)

The 401.17 requirement to use a three-wheel roller to compact cold longitudinal joints, and roller requirements of 401.13 are waived. Compaction requirements of 401.16 are waived except for the last four paragraphs.

Whenever wedge a joint is required, ensure that the wedge for mat thickness 1¾” (44.5 mm) or less is a minimum 6 inches (152 mm) wide, and for mat thickness exceeding 1¾” (44.5 mm) is a minimum 10 inches (254 mm) wide.

Determine the core locations per 446.05 paragraph 5 as soon as practical. To enable contractor coring the same day it is advisable to determine core locations prior to the end of work by estimating production based on production rate and contractor expectations. However, never give all core locations at the beginning of the day or night paving. Ensure coring takes place where marked.

A total of ten (10) cores should be taken. Seven cores will be taken from the mat a minimum 12 inches away form the joint and three (3) cores will be taken from the joint. Cores taken form the joint will be taken from the first sub lot, the last sub lot and one randomly form the (2^nd, 3^rd or 4^th) sub lot. Whether cores should be taken from the confined or unconfined side of the joint should be randomly selected also. Wedge cores from mats exceeding 1¾“ (44.5 mm) thick, should be taken 3 inches (76 mm) away from the joint. Wedge cores from mats 1¾“ (44.5 mm) or less thick, should be taken 6 inches (152 mm) away from the joint. Cores from vertical joints should be taken 4 inches (101 mm) away from the joint regardless of mat thickness. Ensure that sister cores are taken longitudinally as noted in 446.05.

If a cold longitudinal joint is made between the mainline and the shoulder, the shoulder will be considered as a separate lane line and must be incorporated in the lot for coring accordingly. If a hot joint exists, be sure the same equipment and rolling pattern is used on the shoulder. If the contractor does not use the same equipment and rolling pattern on the shoulder, include the shoulder in the lot for coring as noted above.

Ensure that core holes are properly filled and compacted with the same material used in the mat.

After a core sample is obtained, it should be packaged and identified in accordance with current District or Laboratory policy. The sample should be shipped to the District lab as soon as possible. Never leave cores in truck bed overnight. Care should be taken not to damage the core by dropping it, throwing it, or exposing it to excessive heat. Cores should not be stacked in any way. Samples obtained by core sampling are tested to determine the density of the asphalt concrete mix after it has been compacted by the rollers.

Hot Joint Requirement (446.06)

Ensure that a hot longitudinal joint is constructed between the mainline pavement lane and the adjoining shoulder and all ramps and the adjoining shoulders. If a hot longitudinal joint is specified between the mainline pavement lanes, the Engineer may allow the Contractor to construct a cold longitudinal joint between the mainline pavement lanes and the adjoining shoulders, provided that the shoulder will be included in the lot for coring.

Nighttime Paving

For Nighttime paving requirements, refer to the MOP 401.15 Spreading and Finishing.

Documentation Requirements - 446 Asphalt Concrete

1. Sign tickets as receiving agent when possible

2. Document station where material is placed when possible

3. Obtain temperature of mix at project site and place on ticket of load checked

4. Fill out form CA-FP-4

5. Lift thickness if required

6. Document quantities in specific areas

7. Place a statement in daily diary as to type and quantity of rollers.

8. Comply with current test lab policy for sampling each item

a. 446 - A lot is one day’s production. 10 cores are taken randomly per lot and forwarded to test lab with location and data sheet. (403.06-A) Form CA-FP-5, or TE-217

448 Asphalt Concrete

Description (448.01)

This item of work consists of constructing a surface or intermediate course of asphalt concrete mix. The requirements of 401 for (spreading and compacting) the mix and the 441 requirements of (mix design and quality control) apply, except as modified by the 448 specification.

Where density acceptance is specified as per 448.03, testing is performed by the contractor on the mat to control density per Supplement 1055 procedures. The project personnel witness quality assurance testing by the Contractor each day in accordance with supplement 1055.

For this item, 448 samples are taken by the contractor at the asphalt plant and verified by the District lab per 403 procedures. Refer to 403.06 for sampling detail. Plate samples and Hopper samples are no longer required. However, in the event of a mix problem the Engineer or DET may require plate or Hopper sampling at the project.

The contractor should provide an approved Field Quality Control Supervisor (FQCS) as per 403.03, routinely and usually present at the paving site during placement of asphalt concrete pavement.

Density (448.03)

The contractor will conduct density gauge quality control (QC) testing on the asphalt mat in accordance with Supplemental 1055. This specification applies only to projects with at least one continuous mile of paving (excepting bridges, intersections etc.) with uniform (surface or intermediate) courses of 0.75 inch (19mm) or more in thickness.

The contractor must have an updated approved Quality Control Program meeting 403.03 requirements.

The 401.13 Rollers requirements are applicable; however the 401.16 Compaction requirements except for the last 4 paragraphs are waived. The 401.17 Joints requirement for a three wheel roller is waived.

The contractor may use either a nuclear gauge meeting ASTM D 2950 or a PQI Model 300 electromagnetic density gauge. The contractor must provide a standardized gauge on the first day or any time a gauge change occurs. On the first day of production the Contractor will calibrate the gauge (either nuclear or electromagnetic). Cores are taken and tested by the contractor and results recorded on the form TE-Min Density Target (Nuclear or Electromagnetic gauge). The mix maximum specific gravity is used to calculate the core density per Supplement 1055. The Minimum Density Target is then calculated per the equation on the form.

The Minimum Density Target is then recorded on form TE-Mat Density QCQA Report. Form TE-Mat Density QCQA Report covers one day’s testing. If needed, more than one page of this form may be used to cover the day’s production. The contractor technician should maintain adequate compaction and verify by QC tests to attain a minimum of 93 percent density based on the maximum specific gravity. The contractor technician must take a minimum of one test each 1000 feet, and shift the locations transversely (left, center, right). Locations of tests must be documented on the form. The actual percent density must be calculated and documented on the form.

For each day or night’s production the inspector should randomly select two locations for QA testing. One location will be at a location previously tested and recorded on the TE-Mat Density QCQA Report. The other test should be randomly selected at any location on the mat. Both QA tests should be within the traffic control zone, a minimum 500 feet (150 meters) away from the transverse joint constructed at the beginning of the day or night’s production, and a minimum 12 inches (300 mm) away from any longitudinal joint. At each QA test location take three tests (right, center, left), average the three readings and calculate the percent density. The QC technician will perform the testing in the presence of the inspector. The inspector will verify and initial the QA tests’ results as recorded on the TE-Mat Density QCQA Report.

The Contractor should determine the minimum density target in timely manner and report it immediately to the gauge operator.

The inspector should receive a copy of all reports filled out by the QC technician no later than the workday following the production day of the material represented by the report.

If the contractor fails to follow this specification as intended or actual density of the mat is predominantly not as reported conduct a meeting with the contractor Quality Control supervisor and the DET to evaluate reasons for discrepancies and implement changes as needed. If the contractor did not respond with corrections to the noted problems the DET should notify the Quality Control Qualification Committee for review of a possible change to 446 acceptance as detailed in Supplement 1055.06.

Acceptance (448.04)

The District lab and monitoring team handles sampling and acceptance paperwork. However, the following applies if plate samples are taken at the road. The frequency of obtaining a plate sample for 448 mixes is in 403.06. After a plate sample is obtained, it should be packaged and identified in accordance with current District or Laboratory policy. The sample must be shipped to the District lab as soon as possible or as directed by the Engineer or DET. Samples obtained by plate sampling are tested to determine the gradation and binder content of the asphalt concrete mix.

Hopper samples are obtained in lieu of plate samples when the asphalt concrete course being placed is less than 1.25 inch (32 mm). The frequency of obtaining a hopper sample for 448 mixes is in 403.06. After a hopper sample is obtained, it should be packaged and identified in accordance with current District or Laboratory policy. The sample should be shipped to the District lab as soon as possible. Samples obtained by hopper sampling are tested to determine the gradation and binder content of the asphalt concrete mix.

QA tests will be taken from 1^st day or night‘s production and deductions as per the tables in 1055.04 will be applicable.

If the QA tests are below specification requirements the Engineer will determine the deduction per Supplement 1055. Each QA test will represent one half (1/2) day’s production.

a. If only one of the two daily QA average densities is below 92.0 percent but above 91.0 percent the production of that day or night will be approved and no deductions will be made.

b. If one of the two daily QA average densities is below 91.0 percent use Table 1055.04-1 to determine the deduction for one half (1/2) day’s production.

c. If both QA average densities are below 92.0 percent, use Table 1055.04-2 to determine the deduction for one half (1/2) day’s production for each QA test.

Nighttime Paving

For Nighttime paving requirements, refer to the MOP 401.15 Spreading and Finishing.

Additional Forms

The following forms are not required but may be used for supplemental documentation.

1. CA-FP-1 Warranty Asphalt Checklist

2. CA-FP-2 Supplement 1035 Random Selection of Asphalt Concrete Field Samples

3. CA-FP-3 Summary of Bituminous Concrete Quantities

Forms filled out by the contractor technician

1. TE-Mat Density QCQA

2. TE-Minimum Density Target Nuclear Gauge

3. TE-Minimum Density Target Electro-magnetic Gauge

Documentation Requirements - 448 Asphalt Concrete

1. Sign tickets as receiving agent when possible

2. Document station where material is placed when possible

3. Mark on ticket time unloaded when possible, samples taken at plant.

4. Obtain temperature of mix at project site and place on ticket of load checked

5. Fill out form CA-FP-4

6. Lift thickness if required

7. Document quantities in specific areas

9. Assure the TE-Mat Density QCQA report Quality Assurance test values were recorded accurately by the Contractor

10. Comply with current test lab policy for sampling each item

a. 446 - A lot is one day’s production. 10 cores are taken randomly per lot and forwarded to test lab with location and data sheet. (403.06-A) Form CA-FP-5, or TE-217

b. 448 - Tested and accepted by 3,000-ton lots. One test taken randomly every 750 tons (403.06-A). Samples taken at the plant, form CA-FP-2.