Description (251.01)

This work consists of partial depth removal of existing pavement in areas exhibiting surface deterioration, applying tack coat, and placing and compacting asphalt concrete.

Removal of Existing Pavement (251.02)

The Engineer should designate the location and mark the limits of the areas to be repaired. Unless otherwise specified on the plans, extend repair area transversely the full width of a traffic lane and longitudinally along the longitudinal joint. Mark the areas in rectangular shapes enveloping the deteriorated surface. Use aerosol spray paint that should be provided by the contractor. Ensure pavement is removed to the depth shown on the plans and that adjacent pavement is not damaged. If the adjacent pavement is damaged, remove all loose pavement to the depth specified on the plans. The contractor should dispose of removed pavement according to 202.

Placement of Asphalt Concrete (251.03)

The exposed surfaces must be thoroughly cleaned and coated with 407.02 material to fill all cracks and joint openings. The approved 448 asphalt concrete must be placed and compacted in as many lifts as necessary to finish flush with the adjacent pavement surface.

Continuously compact each lift while the material is in a workable condition throughout the depth of the lift.

The final lift must be compacted thoroughly using a Type I pneumatic tire roller that conforms to 401.13. As the rolling progresses, add additional patching material, as necessary, to produce a smooth surface flush with the existing pavement surface.

The contractor should not vary the final lift of each completed section from a testing 10-foot (3 m) straightedge by more than 1/4 inch (6 mm).

Trim to vertical all transverse joints 1.5 inches (38 mm) minimum before placing the final asphalt concrete layer adjacent to the existing pavement, unless the repair area is covered with an overlay of asphalt concrete within 60 days.

If the Contract does not include resurfacing, seal the perimeter surface of the repaired areas 4” (100 mm) wide by applying approved 702.04 asphalt material, RS-1, RS-2, CRS-1, CRS-2, or 702.01 approved binder.

Documentation Requirements - 251 Partial Depth Pavement Repair

1. Mark areas to be repaired in rectangular shapes

2. Remove deteriorated pavement to a suitable depth

3. Dispose of removed pavement as per 203.01

4. Area to be clean and tacked with 407 tack coat

5. Place and compact approved 448 Type I asphalt

6. Location, measure, and pay per 251.04

7. Document on CA-D-6

252 Full Depth Rigid Pavement Removal And Flexible Replacement

Description (252.01)

This work consists of the full-depth removal of existing rigid pavement in areas exhibiting deterioration, correcting the subgrade, placing and compacting asphalt concrete, and restoring the shoulders.

Removal of Existing Pavement (252.02)

Pavement Sawing

The existing pavement is sawed full-depth at the limits established by the Engineer with a diamond saw blade. All diamond saw cuts shall be perpendicular to the surface of the pavement. Normally, the existing concrete pavement thickness is given on the plan. There may be older projects where the existing pavement was built thicker than what specified in the new repair plan. Concrete sawing and removal depths may be as much as 1 inch (25 mm) greater than indicated on the repair plan without additional compensation to the Contractor.

If there is an existing asphalt overlay on the concrete pavement, the Contractor may elect to saw full-depth through the asphalt concrete and the Portland cement concrete. Depending on the thickness of each material, the Contractor may not be capable of sawing through both courses and may elect to make an offset saw cut through the asphalt course and remove enough asphalt to allow room for a diamond saw that would saw full-depth through the concrete pavement. If the Contractor elects to make offset cuts to facilitate the removal, the offset cut will not be measured for payment; only full-depth saw cuts that are made at the limits of the removal are measured for payment. Intermediate saw cuts made by the Contractor to facilitate removal by the lift out method are not measured for payment.

During hot weather, it may be necessary for the Contractor to saw only at night or morning when cooler temperatures prevail. Concrete pavement heats up and expands as temperatures rise during hot summer days. Diamond saw blades could be pinched and locked up by the expanding pavement slabs during sawing. Some contractors use a carbide-tipped saw to cut through the pavement within the repair area. This is permitted provided the contractor does not damage the base under the pavement to be removed. All perimeters saw cuts must be made with diamond saws.

Pavement Removal

Removal of the concrete follows the full-depth sawing operation. The lift out method is required in order not to disturb the base under the pavement and to minimize the damage to the adjacent pavement that is to remain. Holes are drilled within the removal area and lift pins are inserted. The slab or portion of the slab is then removed by lifting the slab vertically with a crane or large backhoe. After lifting, loose debris left behind is removed by hand methods. The pavement removed is disposed of according to 201.

The use of a pavement breaker and backhoe for removal is not permitted unless the Engineer determines that the lift out method is not practical because of extensively deteriorated pavement, existence of asphalt concrete full-depth repairs, or old concrete pavement repairs which are extensively cracked and deteriorated. There will be no additional compensation for removal of the existing pavement with a pavement breaker and backhoe.

Correction of Subgrade (252.03)

Prior to placing the asphalt concrete in the removal area, the base or subgrade below the bottom level of the pavement removed, must be shaped and compacted properly by the contractor to the satisfaction of the Engineer. All vertical faces shall be cleaned and coated with asphalt material according to 401.14.

Placement of Asphalt Concrete (252.04)

The pavement replacement is constructed by placing and compacting Item 301 or 448 Type 2 material in two or more lifts according to 401.16. The first lift, and all intermediate lifts, must be thoroughly and uniformly compacted using suitable mechanical compaction equipment operated over the entire replacement area.

Continuously compact each lift while the material is in a workable condition throughout the depth of the lift.

The contractor should not vary the final lift of each completed section from a testing 10-foot (3 m) straightedge by more than 1/4 inch (6 mm).

If there is an existing asphalt overlay on the concrete pavement, trim to vertical all transverse joints 1.5 inches (38 mm) minimum before placing the final asphalt layer adjacent to the existing pavement, unless the repair area is covered with an overlay of asphalt concrete within 60 days.

If the Contract does not include resurfacing, the perimeter surface of the repaired areas must be sealed 4” (100 mm) wide by applying approved 702.04 asphalt material, RS-1, RS-2, CRS-1, CRS-2, or 702.01 approved PG binder.

After completing repairs, the existing shoulders must be repaired to the condition that existed prior to the repair work.

Documentation Requirements - 252 Full-Depth Rigid Removal and Flexible Replacement

1. Locate and mark all areas to be repaired

2. Measure saw cuts. Full-depth saw cuts are an additional pay item paid by the linear foot

3. Remove deteriorated pavement without damaging adjacent pavement

4. Statement as to where removed material is disposed

5. Shape and compact subgrade

6. Fill hole with 301 or 448 Type II material

7. State type of compaction equipment used and lift thickness

8. Measure and pay for repairs by the square yard

9. Document on CA-D-6

253 Pavement Repair

Description (253.01)

This work consists of removing existing pavement (asphalt concrete, brick, Portland cement concrete or aggregate pavement courses),then shaping and compacting the exposed material underneath the removed sections of pavement, and placing new pavement (asphalt concrete pavement or aggregate and asphalt concrete pavement courses).

The plans will show details about the repairs (location, dimensions, and proposed replacement material).

Removal of Existing Pavement (253.02)

The Engineer should designate the location and mark the limits of the areas to be repaired. Unless otherwise specified, extend repair area transversely the full width of a traffic lane and longitudinally along the longitudinal joint. Mark the areas in rectangular shapes enveloping the deteriorated surface. Use aerosol spray paint that should be provided by the contractor. Ensure that existing deteriorated pavement is removed full depth, unless otherwise shown on the plans. If the adjacent pavement is damaged beyond the designated repair areas, the contractor should remove all loose pavement full depth, or to the depth specified on the plans and replace it at his own expense. The contractor should dispose of removed pavement according to 202.

Placement of Asphalt Concrete (253.03)

The exposed underlying material must be shaped and compacted. Before placing asphalt concrete, all vertical faces of the existing pavement must be cleaned and coated with asphalt material according to 401.14. The replacement material must be placed in appropriate lifts.

Continuously compact each lift while the material is in a workable condition throughout the depth of the lift.

The contractor should not vary the final lift of each completed section from a testing 10-foot (3 m) straightedge by more than 1/4 inch (6 mm).

After completing repairs, the existing shoulders must be repaired to the condition that existed prior to the repair work.

Documentation Requirements - 253 Pavement Repair

1. Locate and mark all areas to be repaired

2. Remove deteriorated pavement without damaging adjacent pavement

3. Statement as to where removed material is disposed. (obtain copy of waste agreement if necessary)

4. Shape and compact subgrade

5. Fill hole with 301 or 448 Type II material

6. State type of compaction equipment used and lift thickness

7. Measure and pay as per 253.04

8. Document on CA-D-6

Note: Form CA-D-6 is provided for measurements.

254 Pavement Planing

Description (254.01)

This work consists of planing the existing pavement and disposing of the cuttings, and if specified in the Contract, patching the planed surface. The pay description indicates the predominant type of pavement.

Equipment (254.02)

The equipment used must have sufficient power and stability to consistently and efficiently meet the requirements of 254.05 and the plans. The equipment must be self-propelled and has sufficient power and stability to consistently and efficiently meet the requirements of 254.05 and the plans. Use equipment with grinding, sawing, or milling type cutters. The cutters are mounted rigidly to the carrier and are adjustable to control the depth of cut and cross-slope. Longitudinal planing action shall be accomplished by using equipment with a suitable carrier wheelbase or with an automatic control system having an external reference. Ensure that cross-slope adjustments or automatic controls are capable of producing a variable and a constant cross-slope, as required.

For small or confined areas, the Contractor may use suitable supplemental equipment or methods approved by the Engineer.

Planing (254.03)

The contractor may make one or more planing passes, as necessary, over the designated area to the depth specified in the plans. Remove irregularities such as bumps, corrugations, and wheel ruts to establish a new pavement surface elevation and cross-slope. Ensure that all cuttings are removed from the surface following each pass.

Before opening the completed area to traffic, the surface shall be thoroughly cleaned of all loose material that would create a hazard or nuisance, or would redeposit into the surface texture.

Monitor and control dust, pavement contamination, and the scattering of loose particles during planing and cleaning operations to acceptable levels.

If damage occurs to the adjacent pavement by planing operations, repair the damaged area by matching the adjacent pavement with the planed area in terms of smoothness and mix type.

If the depth of the planed surface is increased by more than 3/8 inches (9.5 mm), the Department will recalculate the surface area for payment by multiplying the surface area measurement by a factor that equals to the new depth divided by the plan depth.

The Engineer should mark the locations of signal loop detectors and notify the maintaining agency before starting the planing operation.

Surface Patching (254.04)

Mark areas that have spalled pavement or have dislodged unsound pavement. Before patching, the areas shall be clean of loose materials and coated with 407.02 asphalt material. The area shall be patched with Item 448, Type 1 material. Patched areas shall be compacted to be flush and level with adjacent pavement.

Surface Tolerances (254.05)

The surface shall be planed free from grooves, ridges, gouges, or other irregularities detrimental to the safe operation of vehicles on the planed surface.

If the Contract specifies planing without resurfacing, the surface shall be planed to a smoothness of 1/8 inch in 10 feet (3 mm in 3 m). If the Contract specifies resurfacing after planing, the surface shall be planed to a smoothness of 1/4 inch in 10 feet (6 mm in 3 m). The surfaces shall be matched at the edges of adjacent passes within 1/8 inch (3 mm). Ensure that the cross-slope of the planed surface is within 3/8 inch in 10 feet (10 mm in 3 m) of the specified cross-slope.

Documentation Requirements - 254 Pavement Planing

1. Location and/or stations of work

2. Note locations of all loops for traffic signals. Notify proper authority before removing.

3. State type of equipment used

4. Record depth of cut and cross slope grade

5. Statement as to where removed material is disposed (obtain a copy of waste agreement if necessary).

6. State method of removal (air hammer, bobcat, hand tools, etc.) around manholes, water-stops, catch basins, curb drains, etc.

7. Measure and pay as per 254.06

8. Document on CA-D-1A or 1B

255 Full Depth Pavement Removal and Rigid Replacement

General

During the life of concrete pavement, it is sometimes necessary to make repairs to arrest progressive deterioration and to maintain serviceability. Timely repairs restore quality and provide the rideability and life expectancy for which the pavement was designed.

Problems may occur at various stages of the pavement life; it is important that these problems are corrected as the need arises. Corrections are often necessary during construction, and these repairs must be of the highest standard in order to achieve the anticipated pavement life. This section establishes a standard repair procedure and provides uniform application for repairs made prior to completion of the construction contract. These standards are also applicable at any time throughout the pavement life.

Generally, concrete pavement repairs are classified as full-depth pavement replacement and thin-bonded patching. Full-depth replacement applies when the damage is more extensive than surface scaling or spalling, and requires removal and replacement for the full depth of the slab. Thin-bonded patching applies to surface scaling and spalling, spalling at edges and joints, and other surface deterioration that does not extend below the pavement mesh. Thin-bonded patching also is applicable for similar deterioration on bridge decks and especially for spalling associated with insufficient cover over the top mat of reinforcing. ODOT has obtained excellent results for correcting insufficient reinforcing mat cover by removing concrete from below the steel and forcing the steel to a lower position before placing the patching concrete. Compliance with all the provisions of the following standards is necessary to assure durable repairs and to permanently restore the quality of the pavement.

Description (255.01)

When this item is called for, the Standard Construction Drawing BP-2.5 entitled Rigid Replacement applies to the work. The basic process of full-depth repair includes the following:

1. Full-depth diamond sawing

2. Removing the existing pavement full-depth

3. Removing base if specified

4. Compaction of base

5. Drilling dowel bar or tie bar holes

6. Furnishing and grouting dowel bars and tiebars

7. Installing mesh when required

8. Placing, consolidating, finishing and curing concrete

9. Sealing of joints

10. Restoring affected shoulders

Materials (255.02)

Concrete

The concrete to be used must be 499 Class C, S, FS, or MS and it will be called out in the pay item description.

Joint Sealer

The joint sealer used at the interface of the new and existing concrete must be a hot applied joint sealer meeting 705.04 or it may be a preformed elastomeric material meeting 705.11.

Curing Materials

The curing material to be furnished and used must be white-pigmented liquid membrane forming compounds meeting 705.07. The shipping containers must be equipped with mechanical agitators to agitate the material prior to use.

Non-shrink Non-metallic Grout

The dowel and tiebars must be anchored with this material, and must set up within 30 minutes. The specification calls out a Type IV, Grade 3, Class A, B, or C material meeting ASTM C 881. In lieu of these, a polyester, vinyl ester, or epoxy grout may be used. These grouts consist of a Component A (Resin) and Component B (hardening agent).

Reinforcing Steel 709.00

Reinforcing steel for Dowels, Deformed bars, Tiebars, Hook bolts, Wiggle bolts and Coupling must be epoxy-coated steel.

Welded steel wire fabric

Welded steel wire fabric, also called steel mesh, must comply with ASTM A 185.

Dowel bars and Basket Assemblies

Dowel bars and basket assembly wires must be epoxy-coated steel or they may be fiber reinforced polymer (FRP) material.

Removal of Existing Pavement (255.03)

Picture 255.03 A - Full Depth Diamond Blade Saws

The Engineer must mark the limits of the areas to be repaired. The minimum longitudinal length of a repair is 6 feet (1.8 meters). All pavement repairs are the full lane width unless otherwise detailed by the plan.

The existing pavement is sawed full-depth at the limits established by the Engineer with a diamond a saw blade. All diamond saw cuts are perpendicular to the pavement lane centerline. Normally, the existing concrete pavement thickness is given in the plan. There may be older projects where the existing pavement was built thicker than specified in the new repair plan.

Concrete sawing and removal depths may be as much as 1 inch (25 mm) greater than indicated on the repair plan without additional compensation to the Contractor.

If there is an existing asphalt overlay on the concrete pavement, the Contractor may elect to saw full-depth through the asphalt concrete and the Portland cement concrete. Depending on the thickness of each material, the Contractor may not be capable of sawing through both courses and may elect to make an offset saw cut through the asphalt course and remove enough asphalt to allow room for a diamond saw that would saw full depth through the concrete pavement. If the Contractor elects to make offset cuts to facilitate the removal, the offset cut will not be measured for payment; only full-depth saw cuts that are made at the limits of the removal are measured for payment. Intermediate saw cuts made by the Contractor to facilitate removal by the lift out method are not measured for payment.

During hot weather, it may be necessary for the Contractor to saw only at night or morning when cooler temperatures prevail. Concrete pavement heats up and expands as temperatures rise during hot summer days. Diamond saw blades could be pinched and locked up during sawing by the expanding pavement slabs. Some contractors use a carbide-tipped saw to cut through the pavement within the repair area. This is permitted provided the contractor does not damage the base under the pavement to be removed. All perimeter saw cuts must be made with diamond saws.

Picture 255 B – Pavement Removal by the Lift-out Method

Removal of the concrete follows the full-depth sawing operation. The lift out method is required in order to not disturb the base under the pavement and to minimize the damage to the adjacent pavement that is to remain. Holes are drilled within the removal area and lift pins are inserted. The slab or portion of the slab is then removed by lifting the slab vertically with a crane or large backhoe. After lifting, loose debris left behind is removed by hand. The removed pavement is disposed of in accordance with Item 202. Intermediate saw cuts within a longer slab replacement are not measured for payment.

Regardless of the method used to remove the pavement, if the face of the pavement to remain is damaged by the sawing or removal operations, an additional full-depth diamond saw cut is required for the full width of the lane or lanes at a distance from the first cut that encompasses the damaged pavement. The additional pavement repair area and the additional saw cut is not measured for payment.

After pavement is removed from the area to be repaired, an additional saw cut must be made if the face of the remaining pavement or shoulder is deteriorated on the bottom to a height greater than 1/4 of the pavement thickness. The additional saw cut should encompasses the deteriorated areas . The additional saw cut and repair area is measured for payment.

Correction of Subgrade (255.04)

Prior to placing the concrete in the removal area, and before installing dowels or tiebars, shape and compact the subgrade. Any area that has been over-excavated must be filled with concrete.

Picture 255.C - Debris Remaining is Removed by Hand Methods

Picture 255. D - Compaction of Base

If undercut joints at the limits of the repair areas are specified under the existing pavement to remain, the Contractor must be careful when removing the base. Damage to the bottom of the slab that is to remain cannot be tolerated and requires additional removal and replacement. If a backhoe bucket plate is used, exercise care (or use hand methods) to excavate under the existing slab. Undercut work is incidental and included in the pay item.

Drilling Dowel or Tiebar Holes (255.05)

Dowels could be smooth or deformed steel bars. Smooth dowels are 1/2 inch (38 mm) in diameter by 14 inches (355 mm) in length. Fiber-reinforced polymer dowel bars may be used in lieu of smooth steel dowels. Deformed bars are No. 11 (#35M) and 14 inches (355 mm) in length. Check standard construction drawing BP2.5 detailing their use and dimension. Drilling holes for dowels is done with hydraulic or electric drills in a manner that will not spall or damage the existing concrete. These types of drills do not impact the face of the saw cut with as much force as a pneumatic drill. Holes must be drilled with a device that allows independent adjustment of all drill shafts in the horizontal and vertical direction. The device must be capable of drilling a minimum of three holes at one time.

Holes are to be centered at mid-slab within a tolerance of plus or minus 1/2 inch (13 mm). Dowels start 12 inches (300 mm) from the outside edge of pavement and are spaced at 12-inch (305 mm) spacing and stop 24 inches (600 mm) from the adjacent lane to avoid hitting existing tiebars at the longitudinal joint. This will result in ten (10) bars in each 12- foot lane. The Contractor must drill dowel holes parallel to the pavement surface and the centerline otherwise the smooth dowels will not perform properly when the pavement expands and contracts.

Picture 255 D - Hole Drilling Equipment

Holes for dowels or tiebars must be 1 5/8 inches (41 mm) in diameter and a minimum of 7 inches (178 mm) deep into the concrete.

Full-depth repairs that are greater than 10 feet (10 meters) in length will require No. 5 X 24” (# 16M X 600) tiebars or Hook bolts spaced at no more than 30” (760 mm) and not less than 24 inches (610 mm). Check standard drawings BP2.1 and BP-2.5 for more details. Holes for tiebars must be ¾ inches (19 mm) in diameter and a minimum of 12 inches (300 mm) deep into the concrete.Grouting Dowels or Tiebars.

All dowels and tiebars must be grouted into place with an epoxy, polyester, or vinyl ester resin material. The material must be injected pneumatically into the back of the hole and the dowel or tiebar inserted 7 inches (178 mm) into the hole. A nylon or plastic washer (called a grout retention disc) is then pushed flush against the saw cut after the bar is installed to retain the grout in the hole. Sufficient grout must be used to completely fill all voids around the bar, including any spalling at the face of the saw cut. Grout retention discs must be clear or white opaque in color. Other methods of installing dowels or tiebars are not permitted.

Picture 255.E - Typical Grout Equipment

Picture 255.F - Injecting Grout into Back of Hole

Most Contractors doing this work pump the resin and hardener from separate pressure pots; the two materials are mixed immediately before being extruded into the hole through a baffled mixing tube. In cooler temperatures, it may be necessary to heat the grouting materials so the material flows easier and sets up in the required 30 minute time period. Dowels or tiebars must be held in proper alignment until the grout has hardened.

Picture 255.G - Insert Steel Rods w/ Grout Discs in Place

Picture 255.H - Using a Spud Bar to Push Steel Rod into Place

Placement of Portland Cement Concrete (255.06)

Placement of the concrete can begin when the grout around dowels or tiebars has hardened and after smooth dowels are coated with a thin layer of oil or other bond breaking material. Rigid forms are required at the outside edge of the full-depth repair. The concrete is placed in a continuous operation and consolidated with internal vibration.

Picture 255.I - Rigid Forms Installed at Shoulder

Full-depth repairs that are greater than 10 feet (3.0 meters) in length and will be open to traffic within 24 hours of placement will require will require W8.5 or D8.5 wire fabric reinforcement. The clearance from the end of the mesh wires to the edge of the pavement or new transverse joint is 4 ± 2 inches (100 mm ± 50 mm). Check standard drawings BP-2.5 Legend 2 for more details.

Picture 255.J - Longitudinal Screeding of Repair Area

Picture 255.K - Bull Floating the Repair Area

Specifications require that repairs less than 12 feet (3.7 meters) must be screeded longitudinally when striking off the top of the concrete. If the repair is over 12 feet (3.7 meters), the screed must be perpendicular to the centerline. After screeding and floating is completed, the surface must be tested with a 10 foot (3.0 meter) straightedge before the concrete hardens to assure that the transition on and off the repair meets a tolerance of 1/8 inch in 10 feet (3 mm in 3.0 m). Any high or low areas must be corrected and the surface rechecked to assure compliance.

The surface finish of the concrete repair must match the adjacent concrete. If the adjacent pavement is smoothed with a burlap drag, the patch should have the same finish. If the patch texture is different, it may be very noticeable when traveling over the patch at normal traffic speed.

The Contractor has the option of forming the joint at the transverse saw cuts during patch finishing. The forming can be done with a hand tool with the proper joint width and depth with a shape factor (depth to width ratio) is between 1 and 2, as shown on the standard drawing BP-2.5 or an actual wood strip of the proper dimensions can be used as a form. The Contractor may also finish the concrete flush with the adjacent pavement and diamond saw the joint after the concrete has cured and before it is opened to traffic.

After finishing and straightedge checking is completed, the concrete is cured with white pigmented curing membrane as per 451.10. This section requires a uniform coverage of membrane at an application rate of 150 square feet per gallon (1 liter per 3.7 square meters).

Sealing of Transverse Joints

Transverse joints must be sealed with a hot applied joint sealer meeting 705.04. Prior to sealing the joint, both vertical faces of the joint must be cleaned by abrasive blasting to the depth of the bottom of the sealer. The cleaning must remove all dirt, dust, tar or asphalt, and curing compound discoloration, leaving a clean dry newly-exposed surface to seal. The hot applied sealer must be 1/4 inch (6 mm) below the surface of the pavement. A bond-breaking tape is placed at the bottom of the prepared joint immediately before the hot applied material is placed.

Classes of Concrete

The pay item description for Item 255 specifies the class of concrete. The classes of concrete used for this item will normally be Class C, S, FS, or MS. These classes of concrete are described in 499.

Joint Repair Using Rapid Strength Concrete With Maturity

Rapid strength concrete for this project will conform to 499.05A modified as follows:

1. A minimum cement content is not required

a. Only use cement conforming to 701.02, 701.04 or 701.05

2. Do not use calcium chloride.

3. Only use aggregates conforming to

a. Fine 703.02.A natural sand

b. Coarse 703.13

4. Working with established admixture producers of rapid repair systems, develop and test a concrete mix design to achieve at least 400 psi in time determined by the contractor but in no less than 4 hours. Use 6” x 6” beams, tested conforming to ASTM C293, to determine and document the 400 psi achievement. Developed mixes should demonstrate shrinkage no greater than a standard Class C mix. Shrinkage testing may not be required if the admixture producer can show shrinkage data from similar mixes.

a. Admixture based rapid repair systems include

i. 4 x 4 concrete system of Degussa

ii. Rapid-1 by Sika

b. While testing the concrete mix to determine it’s ability to achieve the 400 psi, also perform maturity testing using a flexural beam sample.

i. All samples will be prepared by ACI Concrete field testing technician Grade 1

c. Before performing the maturity testing of the mix, determine which maturity method will be used for both the mix design’s maturity curve development and for measuring the actual maturity in the field.

i. Document the equipment type to be used,

ii. Where thermocouples will be located in the mix design testing and the actual pavement to measure temperature for determining maturity

iii. Document time measurement devices to be used,

iv. Document all other equipment and processes required to describe how the both the mix design maturity testing will be performed and the curve developed and how the field maturity testing will be performed and strength-maturity curve determined.

d. After acceptance of the maturity method, equipment and processes, perform maturity testing of the mix to determine time-flexural strength curves that can be used in the field to determine the in-place maturity and flexural strength of the concrete.

i. Perform the maturity testing of the actual mix assuring the mix is at its maximum w/c ratio and maximum air content. (if air content will be 6 +/- 2% the test will be run at 8% +/- 1/2%.

5. Provide the Engineer with the mix proportions, quality control requirements, and test results of the mix, time-temperature and maturity curve results. The Engineer will determine if the mix design meets specification requirements.

Project Acceptance.

a. Open concrete pavement to traffic based on the field tested, verified, maturity result that show the pavement achieved at least 400 psi flexural strength.

b. Maturity testing verification will include.

i. Documenting the delivered mix design, based on actual batch tickets, is equal to the original mix design.

1. Actual w/c is less than or equal to the original test mix

2. Admixtures are the same brand

3. Aggregates and cementatious materials are the same source

4. Air content is within the specified range.

ii. Weekly verification flexural beam testing. Perform maturity verification by making three (3) 6” x 6” beams from the same concrete batch used in the pavement where the last thermocouple is installed. When the maturity readings determine the pavement has achieved 400 psi, test the three (3) beams.

1. Samples will be prepared by ACI Concrete field testing technician Grade 1

2. Verification will be acceptable if the beam results are 80% or greater of the maturity curve’s projected results for the flexural strength of the concrete pavement.

6. Payment.

a. The Department will determine flexural strength of the concrete by using the verified maturity curve. When the maturity reaches the point on the curve equal to 400 psi flexural strength the pavement may be opened to traffic.

b. The Department will pay 100% of the unit bid price for concrete pavement obtaining a flexural strength of 400 psi.

c. Concrete pavement with less than 400 psi flexural strength will be removed and replaced

Wearing Course Replacement (255.07)

If asphalt was removed from the top of the existing pavement, it must be replaced with either 301 or 448 Type 2 material as shown in the plans. Compact these mixtures as approved by the Engineer using any of the roller types specified in 401.13. Prior to placing the hot mix asphalt concrete; apply a tack coat on the repaired surface per 407.

Trim to vertical all transverse joints 1.5 inches (38 mm) minimum before placing the final asphalt concrete layer adjacent to the existing pavement.

Seal 4” (100 mm) wide the perimeter surface of the repaired areas by applying approved 702.04 asphalt material, RS-1, RS-2, CRS-1, or CRS-2

Shoulders must be restored to the original line and grade with aggregate or asphalt concrete as the Engineer directs or as shown in the plans. Fill low areas and compact them flush with the surrounding shoulder.

Opening to Traffic (255.08)

Full-depth repairs can be opened to traffic when the flexural strength of 400 psi (2.7 Mpa) is attained. The time to obtain this strength will vary depending on the class of concrete used and the atmospheric conditions.

When traffic is adjacent to the lane being repaired, the Contractor must schedule his work so that slab replacements are completed within 48 hours. Repairs must not be left open overnight. Repairs 10 feet (3.0 meters) and less in length may be covered with steel plates at the end of the day.

The Contractor must plan work so that no repairs are left unfilled when work is suspended for holidays or weekends. If the Contractor has removed pavement and is unable to complete the repairs in the above time, he must fill the areas with a suitable temporary patch material to the satisfaction of the Engineer. These areas must be maintained by the contractor.

Method of Measurement (255.09)

The Department will measure the quantity of full-depth pavement removal and rigid replacement by the number of square yards (square meters) repaired in the completed and accepted work.

Full-depth pavement sawing is measured by the number of feet (meters) of perimeter full-depth saw cuts made in the completed and accepted work. The Department will not measure any offset cuts, pressure relief cuts, or other saw cuts made to facilitate pavement removal.

Basis of Payment (255.10)

Payment is full compensation for all work specified in this item. Payment for accepted quantities of the full-depth pavement removal and rigid replacement item is at the contract price per square yard (square meter).

Payment for the full-depth pavement sawing item is at the contract price per foot (meter).

The Department will not pay for additional work to repair damage caused by pavement sawing or pavement removal.

The Department will include tack coat in the cost of the asphalt concrete. The Department will pay for asphalt concrete according to Item 301 or Item 448.

Documentation Requirements - 255 Full Depth Pavement Removal and Rigid Replacement

1. Locate, mark, and record areas to be replaced

2. Existing pavement removed without damage to adjacent pavement

3. Statement as to where removed material is disposed (Waste agreement if necessary).

4. State if existing subgrade was damaged in removal operation and method of compaction.

5. Type of equipment used for drilling holes for dowel bars. Depth of hole. Holes blown clean before dowel bars placed.

6. Grout placed and dowels held in proper alignment until grout was set

7. Concrete placed in patch in accordance with 451.06

8. Surface checked with straight edge and all irregularities corrected to meet adjacent pavement

9. Calculate and document curing compound used and required

10. Document times and results of beam breaks

11. Measure and pay as per 255.10.

12. Document on CA-D-6.

256 Bonded Patching of PCC Pavement

General

The success of a thin-bonded patch depends on complete removal of all unsound or damaged material, adequate bond between old and new concrete, use of “low slump” air-entrained concrete, and proper curing. Successful patching depends on strict adherence to all these requisites.

Description (256.01)

This work involves bonded patching of Portland cement concrete pavements in areas designated by the Engineer. The work involves:

1. Marking using aerosol spray paint the repair areas, minimum payment is 2 square feet (0.2 m^2) for each area.

2. Saw cutting the perimeter of all areas marked for repair

3. Removal of all loose and unsound concrete and asphalt patching materials from within the repair area.

4. Removing sound concrete as directed maintaining minimum depth of 1 ½ inch (38 mm).

5. Preparation of the surface by cleaning bonding surfaces by abrasive blasting.

6. Applying a bonding grout for type A, and if required by manufacturer for types B & C.

7. Reconstructing joints using joint board.

8. Mixing, placing, finishing, and curing of the patching material that is called out in the pay item description.

9. Checking surface for trueness using 10-foot (3 m) straightedge.

Materials (256.02)

Portland cement

For this work item, use only Type III cement in Type A patches. This is high early strength Portland cement 701.05.

Fine aggregate

The fine aggregate must meet the requirements for concrete aggregate specified in 703.02.

Coarse aggregate, No. 8 size

The coarse aggregate must meet the requirements for concrete aggregate specified in 703.02 and be No. 8 size.

Curing Material 705.07

Curing compound must meet the requirements of ASTM C 309 705.07.

Air-entraining admixture

Air entraining admixtures must conform to AASHTO M 154 705.10.

Quick setting concrete mortar

Prepackaged mortar material conforming to the requirements of 705.21.

Equipment (256.03)

Equipment must be milling machines, concrete saws, jackhammers, or other approved equipment that is capable of removing the existing surface material. The chipping hammers used may not be heavier than 35-pound (16 kg) class.

Oil and moisture free compressed air is required to clean and abrasive blast prepared areas.

An on-site concrete mixer of a minimum capacity of 2-cubic feet (0.06 cubic meters) is required to mix the patching material.

Removal of Unsound Concrete (256.04)

Picture 256.A - Areas to be Repaired are Marked by the Engineer

Picture 256.B - Perimeter of the Repair is Saw Cut a Minimum of 1 inch Deep

The limits of the damaged area must first be determined and the repair area established beyond the affected area into sound concrete. A steel rod or steel chain may be used to sound the surface to determine hollow and unsound areas. The Engineer marks the limits of all bonded patches with spray paint provided by the Contractor.

Picture 256.C – Pavement Removal with Jackhammer

Picture 256.D - Pavememt Removal by Milling Machine

Generally, the area should be square or rectangular and the perimeter should be outlined by sawing to a depth of approximately 1 inch (25 mm) to avoid feathered edges that usually spalled. Additional saw cuts within the outlined area aid the breakup and removal operation. The contractor must remove all unsound concrete asphalt materials and all loose or disintegrated concrete within the marked area. Sound concrete must be removed to the minimum required depth within the patch area. Concrete removal may be by jack hammering or milling. The minimum depth of a repair is 1 1/2 inch (38 mm) except for the perimeter saw cuts that require 1 inch (25 mm) minimum. During removal operations, remove any reinforcing steel within the patch area by cutting or with a torch.

Picture 256.E - Abrasive Blasting of Repair Areas

Preparation of Patch Area (256.05)

After removal of pavement within the repair area the area must be cleaned of all loose material, dirt, dust, asphalt materials etc., by abrasive blasting and blowing out with oil and moisture free compressed air. If water is used for cleaning, it must be mopped out thoroughly before abrasive blasting. Abrasive blasting of the bonding surfaces must be done after the area has dried. The contractor must comply with all State, regional and local government agency requirements regarding control of dust generated by the abrasive blasting operation.

If a bonded patch area is adjacent to a transverse or longitudinal joint, the joint must be recreated by using a joint board or form that extends below the level of the patch and is as wide as the joint. This board is to be removed about an hour after placing the patching material.

Picture 256.F – Adjacent Joints are Formed Prior to Placing the Patching Material

Bonding Grout Installation (256.06)

A neat cement grout of non-air-entraining cement and water having a consistency of a thick paint should be brushed into the cleaned bonding surface of the exposed concrete. Care should be exercised to see that:

1. The bonding surface is damp but free of surface water when the grout is applied.

2. The grout is brushed into the surface to displace all air films and to provide a uniform thickness of 1/16 to 1/8 inch (2 mm to 4 mm).

3. The grout is not placed so far in advance that it dries out before being covered with the patching material.

Picture 256.G - Portable Mortar Mixer used to Mix Bonding Grout and Patching Material

Picture 256.H - Bonding Grout is brushed into the dry patch area if required

Types of Patching Material

The use of “low slump” concrete is necessary to avoid shrinkage upon drying and hardening, thereby obtaining good bond with the adjoining concrete. The Contractor must use Type A, Type B, or Type C patching material as defined below and as called out in the pay item description.

Type A Patch

This type of patch material is to be mixed in the field using high-early-strength cement (Type III). Ready mixed concrete is not permitted. The principal requirements of this patching material are that it has only enough water to make it cohesive and that it has sufficient air entrainment. A mixture of cement, water, sand, and No. 8 size coarse aggregate is mixed with an air-entraining agent to obtain 8 + 2 percent entrained air. One part of cement is combined with 1 ½ parts of sand and 1 ½ parts No. 8 size coarse aggregate and enough water to obtain a slump practical to place in the patch area. The slump must not exceed 4 inches (100 mm).

A grout made of equal parts of cement and sand, mixed with enough water to produce stiff slurry, is brushed on to the surface to be patched immediately prior to placing the concrete mixture. Place the patching material while the grout is still wet, and vibrate the concrete in place after the patch area is slightly overfilled. Strike off the concrete to the elevation of the adjacent concrete.

Type B Patch

This type of patching material is a quick-setting mortar that comes prepackaged. The patching material must be pre-approved and must comply with 705.21 as Type 1 or 2 material.

Mix and place the material according to the manufacturer’s recommendations. Add coarse aggregate, as needed, according to the manufacturer’s instructions. Place the concrete mixture in the patch area. If the manufacturer’s requirements specify using bonding grout, place the concrete mixture while the bonding grout is still wet. Slightly overfill, vibrate, and strike off the concrete.

Picture 256.H - Patching Material Placed and Consolidated with an Internal Vibrator

Picture 256.I – Patching Material Screeded Off Flush with Surrounding Pavement

Type C Patch

This type of patching material is also a quick-setting mortar that comes prepackaged. The patching material must be pre-approved and must comply with 705.21 as Type 2 material.

Screed patches 12 feet (3.7 m) and less in length parallel to the roadway centerline. Screed patches greater than 12 feet (3.7 m) in length perpendicular to the centerline. A 10-foot (3 m) straightedge must be used to check the pavement for irregularities. All high or low areas exceeding 1/8-inch in 10 feet (3 mm in 3 m) must be corrected prior to the patching material hardening.

The texture of the patch must be the same as the adjacent pavement.

Picture 256.J – Application of Curing Compound to New Bonded Concrete Patch

Picture 256.K – Completed Bonded Patches

Curing and Loading (256.08)

Type A patches must be cured with a white-pigmented liquid membrane-forming compound conforming to 705.07 and applied at a rate of 150 square feet per gallon (1 Liter per 3.7 square meters). A flexural strength of 400 psi (2.8 Mpa) must be obtained prior to opening to traffic. Cure Type B and Type C materials according to manufacturer’s recommendations.

Method of Measurement (256.09)

Project personnel must measure the repair areas and calculate the area in square feet (square meters) of completed and accepted work. If a measured area is less than 2 square feet (0.2 square meters) the Engineer will increase these measured patches to 2 square feet (0.2 square meters).

Basis of Payment (256.10)

Pay the contract price for accepted quantities per square feet (square meters) of Item 256, Bonded Patching of Portland Cement Concrete Pavements.

Documentation Requirements - 256 Bonded Patching of Portland Cement Concrete Pavement

1. Remove unsound material.

2. Prepare area and apply grout.

3. Material (256.02); equipment (256.03).

4. Document type of patch material (256.07).

5. Measure and calculate the area of the repair for payment.

6. Areas measured found to be less than 2 square feet (0.2 m²) are to be paid for as 2 square feet (0.2 m²).

7. Document on CA-D-6, Pay 2 SF if actual area of patch is less than 2 SF.

257 Diamond Grinding Portland Cement Concrete Pavement

Description (257.01)

This work consists of diamond grinding of a rigid pavement normally full width of the lane to eliminate transverse crack and transverse joint faulting. The work results in a longitudinal corduroy texture. If done properly the ride of the finished pavement surface will be substantially improved and the skid resistance of an old pavement will also be enhanced.

Acceptance of a diamond ground pavement is done by surface measuring equipment that is passed over the completed pavement which measures the profile. This equipment is called a non-contact profilometer.

Equipment (257.02)

Figure 257.A - Types of Diamond Grinding Equipment

Requirements of the equipment for diamond grinding the pavement:

· It must be power driven, self-propelled machine specifically designed to smooth and texture Portland cement concrete pavement with diamond blades or diamond impregnated cylinder rings

· Diamond blades or diamond impregnated cylinder rings must be mounted on an arbor head that is a minimum of 3 feet long.

· The equipment must be capable of grinding the surface in the longitudinal direction without causing spalling or other damage at cracks, joints and other locations.

· The equipment must be capable of correcting the pavement profile and providing proper cross slope transversely across the pavement.

· The effective wheelbase of the equipment must be at least 12.0 feet (3.6 m) and a set of pivoting tandem bogey wheels at the front of the machine and rear wheels that travel and track in the fresh cut pavement.

· The center of the grinding head must not be further than 3.0 feet (0.9 m) forward from the center of the back wheels.

· Equipment must be configured such that it does not encroach on traffic movement outside of the work area in adjacent lanes.

· Equipment must be designed to remove all grinding residue. Grinding residue is not permitted to flow across lanes being used by the traveling public.

Requirements for surface measuring equipment:

· A surface measuring device conforming to Supplemental Specification 1058 must be used. This is a low speed non-contact profile measuring device that can develop a Profile Index trace the same as a California Test 526, 1978.

· All necessary supplies must be provided to fully operate and graph the smoothness test results on the diamond ground pavement.

Contractors doing diamond grinding work use water trucks that provide water to the grinding heads of each grinder to cool the diamond blades.

Construction (257.03)

The plans will designate the areas to be diamond ground. Bridge decks, bridge approach slabs and roadway shoulders are not normally diamond ground unless indicated on the plans or required to provide drainage. Diamond grinding must eliminates crack or joint faults while providing positive lateral drainage by maintaining a constant cross-slope between grinding extremities in each lane. Adjacent ramp lane grinding must be transitioned as required from the mainline edge to provide positive drainage and an acceptable riding surface.

The diamond grinding operation must results in pavement that conforms to the typical cross-section and the requirements specified for the final surface finish. It is the intention of this specification that the faulting at joints and cracks is eliminated and the overall riding characteristics is restored within the limits specified. To accomplish the smoothness required, diamond grinding may not be required on 100 percent of the existing pavement surface.

Contractors doing this type of work normally will grind the pavement in the opposite direction that traffic travels in its normal configuration. The reason for this is that the pavement is faulted at joints and cracks with the rear slab (in the direction of travel) lower than the forward slab. By grinding opposite the normal traffic flow, the contractor is able to cut the step in the pavement first and can feather the fault out though the slab length.

During initial grinding operations, the profiler must be used to test the pavement surface as soon as the concrete has been ground full lane width. This initial testing is to aid the Contractor in evaluating the grinding methods and equipment being used. Subsequent to the initial testing, the contractor must run daily profiles of each day's grinding the next working day.

Final Surface Finish

Figure 257.B - Surface Texture Left by Diamond Grinding

The final surface finish produced should be a longitudinal corduroy-type texture. The peaks of the ridges of this corduroy-type texture are to be approximately 1/16 inch (1.5 mm) higher than the grooves. There must be 53 to 57 evenly spaced grooves per foot (174 to 187 per meter).

Figure 257.C - Profile Measuring Device

Figure 257.D - Typical Profile Trace

The pavement surface must be tested by the contractor with a device that prints out a Profile Index trace in accordance with a California Test Method 526 (78). The contractor must produce a riding surface with a Profile Index that does not exceed 12 inches per mile for each 0.10 mile length of pavement. The contractor tests each wheel path of each 0.10 mile section and averages the readings and that average must be 12 inches per mile or less.

Wheel paths are to be located 3 feet (0.9 m) measured transversely inside all lane edges. The profiler is to be maintained at the wheel path at all times when testing the pavement.

Any 0.10 mile sections of diamond ground pavement with wheel path averages greater than 12 inches per mile must be re-ground and re-tested until the Profile Index of 12 inches per mile or less is achieved.

The contractor must provide traffic control and survey stationing necessary for testing the pavement. Profile measuring equipment is to stop within 1 foot (0.3m) of any existing pavement not ground, any pressure relief joint or any approach slab to a bridge.

Inspection should include spot testing the pavement with a 12 foot straightedge transversely and longitudinally to assure that the pavement complies with straightedge tolerances. The tolerance is ¼ inch in 12 feet (6 mm in 3.6 m) for transverse cross slope. The alignment of transverse joints and cracks must be within + 1/16 inch of each other.

Method of Measurement (257.05)

The Department will measure pavement grinding on existing pavements by the square yard (square meter) of pavement ground and accepted. The quantity of pavement grinding will be determined by multiplying the width specified on the plan by the total length of the finished pavement surface measured in the field, excluding bridge decks, approach slabs and other areas designated by the Engineer.

Basis of Payment (257.06)

Payment is full compensation for furnishing all labor, materials, tools, equipment and incidentals and for doing all work involved in grinding the existing surface, removing residue, cleaning the pavement, and testing with a profiler conforming to the plans and specifications.

Documentation Requirements - 257 Diamond Grinding Portland Cement Concrete Pavement

1. Check pavement grinding equipment prior to use to assure compliance as to width of diamond grinding head, number of grooves per foot, vacuum system, etc.

2. Check pavement smoothness testing equipment for compliance. Obtain ODOT certification of the equipment from the contractor.

3. Measure length of pavement diamond ground and use the plan width to calculate area for pay.

4. Document area calculations on CA-D-3A or CA-D-3B

258 Dowell Bar Retrofit

General

This is a rehabilitation technique that is normally specified to restore load transfer at faulted transverse cracks in older concrete pavements. It has also been used in new construction when a dowel bar installing equipment on a concrete paving machine inadvertently fails to install dowels at contraction joints. Standard Construction Drawing BP-2.6 Dowel Bar Retrofit is to be followed when constructing this item of work.

Description (258.01)

The work involves the following:

1. Sawing the proper size slots across transverse cracks.

2. Cleaning the slots

3. Injecting a silicone calking filler to seal the crack and filler board as specified.

4. Placing a smooth epoxy coated steel dowel bar 1-1/2 inch in diameter with appropriate chairs, expansion caps and ½ inch thick filler board in each slot.

5. Filling the slot with one of the specified cementitious patching materials.

6. Consolidate, finish and cure the cementitious patching material.

7. Establishing a joint by sawing.

Equipment (258.03)

Equipment for sawing slots in the pavement must be power driven gang type assemblies with diamond saw blades that are capable of sawing a minimum of three slots at a time. Saws must not damage the existing pavement.

Picture 255.A – Slot Sawing Equipment

Jack hammers must be less than a 30 pound (13.6 kg) class.

Abrasive blast equipment must be capable of removing the saw slurry and other foreign material from the exposed surfaces of the sawed slot leaving a clean, newly exposed concrete surface free of spalls, laitance, and all contaminants detrimental to achieving an adequate bond. If wet blasting is used, ensure water blasting pressure with abrasives in the water is 10,000 psi (690 bar) or less.

Construction (258.04)

The Engineer must mark the transverse cracks to be retrofitted with dowels. The contractor will provide the spray paint. The contractor must position the slots as shown in the standard drawing RETROFIT DOWEL BAR SPACING BP-2.6.

The sawing must done to the specified width of 2 ½ inches (65 mm) and to a length as needed to allow the centering of the dowel at the transverse crack. The slot must be sawed deep enough to assure that the dowel, when installed with the ½ inch tall prefabricated chairs, is level and located at mid-depth in the concrete slab. The slots must be parallel to the centerline of the pavement. The contractor may make multiple parallel saw cuts within the 2 ½ inch width to facilitate removal of concrete, and to provide a level surface for the feet of the dowel bar chairs. Six slots are to be cut in each lane at each crack, three slots at one foot (0.3 m) centers in each wheel path, as shown in BP-2.6.

Picture 258.B - Saw Cuts for Three Slots

Picture 258.C - Concrete Removal by Light Weight Jack hammer

Once sawing is complete concrete is removed carefully within the 2 ½ inch slot using lightweight jack hammers 30 pounds (13.6 Kg) or less. Once concrete is removed, traffic must be kept off of the slots until the patching material is placed and cured.

It is permissible to do all of the sawing within an area and open the pavement for a period of time, but once the concrete is removed traffic must be prohibited from using the pavement.

Once concrete is removed within the sawed slots to the proper depth, cleaning of the slots can begin. Inspection should include checking the slot depth to assure the bottom of the slot is level and to the proper depth. Cleaning must be done by approved abrasive blasting (wet or dry) which will produce a rough surface on the sawed faces of the slots. The contractor’s abrasive blasting operation must not damage the surrounding pavement. Do not allow the contractor to begin abrasive blasting operations unless reasonably available engineering controls are implemented to limit fugitive dust. The contractor must conform to state, regional, and local government agency requirements regarding control of dust generated by the blasting operation.

Picture 258.D – Dry Abrasive Blasting

Picture 258.E – Blowing Out Slots Air Blast

After cleaning of the slots, calk the cracks with silicone material at the bottom and along the sides of the cleaned slot. The purpose of the calking is to keep the patching material from entering the crack when the patching material is placed in the slot. The calking material must be forced into the crack under pressure. Care must be taken to be neat and not contaminate the cleaned slot face in adjacent areas.

Pictures 258.F - Dowels Installed in Prepared Slots at Transverse Cracks

Next dowel bars are placed into the prepared slots. Inspectors must assure the contractor follows these dowel placing requirements:

1. Dowels must be 1 ½ inch (13 mm) in diameter and 18 inches (460 mm) long. The dowel is to be centered on the crack.

2. Coat each dowel with a thin coating of oil just prior to installation in the slot.

3. The dowel must have the 1/2 inch (13 mm) thick preformed filler board centered on the dowel to maintain the crack across the slot, as shown in BP-2.6. This filler board must fit tight around the dowel and extend to the bottom and to the edges of the slot. The filler board must be maintained in a vertical position and be tight to all edges during placement of the patching material. Use the silicone calking material on the bottom of the preformed filler to keep the patching material from flowing under it. The filler board must extend from the bottom of the slot to no more than 1 1/2 inches (38 mm) from the top surface of the pavement.

4. When a dowel is installed there must be an expansion cap on both ends of the dowel which allows for ¼ inch (6 mm) movement.

5. Normally the two dowel chairs are also attached to each dowel prior to installation into the slot. These dowel chairs must firmly hold the dowel bar centered in the slot at the proper elevation of ½ inch (13 mm) from the slot bottom. Inspectors must reject any chair design that allows movement of the dowel bar during placement of the patching material.

6. Once the dowels are in place in the proper location the contractor must make several passes of an air blast throughout each slot to provide a dust free slot to assure adequate bonding of the patch material.

Next the patching material is mixed, placed and cured per the material manufacturer’s recommendations. The patching materials specified are prepackaged proprietary cementitious materials which may allow the use of a certain amount of aggregate of a certain grading to be blended with each bag. The contractor must provide one of the approved patching materials listed in the Departments Qualified Products List (QPL).

Picture 258.F - Portable Mortar Mixer

Picture 258.G - Filling Slots with Patching Mix

The patching materials are mixed in the field in a portable mixer. When the material is placed into the prepared slot it must be consolidated with an Engineer approved internal vibrator and screeded off flush with the adjacent pavement. The surface is cured per the manufacturer’s recommendations which are normally by the use of a white pigmented spray curing compound.

Within 4 hours after placing the patching material the contractor must saw cut a 1 1/2 inch (38 mm) deep by 1/4 inch (6 mm) wide saw cut over top of the ½ inch (13 mm) thick preformed filler board using a hand pushed single blade saw. The reason for this saw cut is to re-establish the crack above the filler throughout the patching material.

Picture 258.H – Internally Vibrating Patch

Picture 258.I – Patches Cured with Spray Cure

Method of Measurement (258.05)

The Department will measure the quantity of Retrofit Dowel Bars by the actual number of slots each that are accepted.

Basis of Payment (258.06)

Payment is full compensation for furnishing all materials including paint; sawing and cleaning the slots; installing dowel chairs, dowels, bond breaker material, dowel bar end caps, sealant/caulking material, filler material, and patching material; and re-establishing the crack.

Documentation Requirements - 258 Dowel Bar Retrofit

1. Check and document equipment for compliance prior to commencing work.

2. Check and document all dowels (diameter, length and epoxy coating) and dowel hardware (expansion caps, dowel chairs and ½ inch wide preformed filler board) for compliance.

3. Document compliance to specification requirements (slot location, width and depth of slot, etc.

4. Document the number of slots performed each day for payment.

5. Pay the unit bid price for Dowel Bar Retrofit.

250 Pavement Repairs

252 Full Depth Rigid Pavement Removal And Flexible Replacement

253 Pavement Repair

254 Pavement Planing

Description (254.01)

Equipment (254.02)

Planing (254.03)

Surface Patching (254.04)

Surface Tolerances (254.05)

Documentation Requirements - 254 Pavement Planing

255 Full Depth Pavement Removal and Rigid Replacement

General

Description (255.01)

Materials (255.02)

Concrete

Joint Sealer

Curing Materials

Non-shrink Non-metallic Grout

Reinforcing Steel 709.00

Welded steel wire fabric

Dowel bars and Basket Assemblies

Removal of Existing Pavement (255.03)

Correction of Subgrade (255.04)

Drilling Dowel or Tiebar Holes (255.05)

Placement of Portland Cement Concrete (255.06)

Sealing of Transverse Joints

Classes of Concrete

Wearing Course Replacement (255.07)

Opening to Traffic (255.08)

Method of Measurement (255.09)

Basis of Payment (255.10)

Documentation Requirements - 255 Full Depth Pavement Removal and Rigid Replacement

256 Bonded Patching of PCC Pavement

General

Description (256.01)

Materials (256.02)

Portland cement

Fine aggregate

Coarse aggregate, No. 8 size

Curing Material 705.07

Air-entraining admixture

Quick setting concrete mortar

Equipment (256.03)

Removal of Unsound Concrete (256.04)

Preparation of Patch Area (256.05)

Bonding Grout Installation (256.06)

Types of Patching Material

Type A Patch

Type B Patch

Type C Patch

Curing and Loading (256.08)

Method of Measurement (256.09)

Basis of Payment (256.10)

Documentation Requirements - 256 Bonded Patching of Portland Cement Concrete Pavement

257 Diamond Grinding Portland Cement Concrete Pavement

Description (257.01)

Equipment (257.02)

Construction (257.03)

Final Surface Finish

Method of Measurement (257.05)

Basis of Payment (257.06)

Documentation Requirements - 257 Diamond Grinding Portland Cement Concrete Pavement

258 Dowell Bar Retrofit

General

Description (258.01)

Equipment (258.03)

Construction (258.04)

Method of Measurement (258.05)

Basis of Payment (258.06)

Documentation Requirements - 258 Dowel Bar Retrofit