525CONCRETE PAVEMENT PARTIAL-DEPTH REPAIR

525.1DESCRIPTION —This work is the construction of a partial-depth repair of an existing concrete

pavement. This type of repair is suitable for use on transverse or longitudinal joints , cracks, and interior slab spalls if the depth of the repair is no greater than half the slab thickness. Areas requiring repair depths greater than half the slab thickness will be repaired with full-depth concrete pavement patches or corner repairs, as specified in Section 516. Concrete pavement partial-depth repair is classified by two types as follows:

cracks, and interior slab surface spalling between 15 inches and 6 feet in length.

longitudinal joints, cracks, and interior slab surface spalling in lengths greater than 6 feet.

525.2MATERIAL—

except as follows:

• Coarse Aggregate, Type A, No. 8—Section 703.2

• Maximum Water Cement Ratio (lbs/lbs) 0.42

except as follows:

• Coarse Aggregate, Type A, No. 8—Section 703.2

• Maximum Water Cement Ratio (lbs/lbs) 0.42

Submit mix design having a minimum target value of 1,500 pounds per square inch compressive strength at 7 hours, when tested according to PTM No. 604.

requirements of ASTM C928. The material must be tested and meet the minimum test results for the ASTM and AASHTO test methods outlined below:

• The material must have a minimum durability factor of 80% at 300 cycles when tested according to ASTM C666 (procedure B) with and without aggregate extenders.

• A minimum initial set time of 15 minutes at 75F ± 2F as tested according to AASHTO T 131.

When the depth of the repair is greater than 2 inches, use aggregate extenders according to the manufacturer’s recommendations. Use only aggregate extenders included with the prepackaged rapid -set concrete patching material. If aggregate extenders are not included as part of the prepackaged rapi d-set concrete patching material, use AASHTO No. 8 coarse aggregate from a Bulletin 14 approved supplier with an expansion index less than 0.10, and only if allowed in writing by the material manufacturer. Use within the shelf life and temperature limitations set by the manufacturer.

Cement Water Fine Aggregate 2 1 1

Must be placed within 60 minutes of mix completion.

and as follows: Provide a copy of the manufacturer's written installation instructions to the Representative. Use epoxy bonding compound within the shelf life established by the manufacturer. Apply the epoxy bonding compound within the application setting times (working or pot life) and temperature limitations established by the manufacturer.

525.3CONSTRUCTION—

repair as specif ied in Section 106.03(a) 2. Detail appropriate action points for all phases of construction including: removing unsound concrete, concrete mixing and curing, joint sawing and sealing, and sampling and testing for opening to traffic.

the extent of the concrete delamination using a steel bar, drag chains, or a hammer . Lay out rectangular repair limits to extend approximately 3 inches beyond the edges of the delaminated area. All repair areas will be rectangular, with minimum dimensions of 15 inches in length by 10 inches in width by 2 inches in depth. If partial-depth repair areas are less than 24 inches apart, combine them into one partial-depth repair. For areas where delamination extends through a pavement joint, the area should be repaired by maintaining the joint with two separate minimum repair areas unless a detailed procedure for reestablishing the joint and protecting the adjacent joint and crack from mortar intrusion is included in the QC Plan .

depth of 2 inches and a maximum depth of half of the slab thickness. For Type 1 partial-depth repairs only, saw cut the perimeter of the repair area to a minimum depth of 2 inches. Remove the existing concrete within the repair area to a minimum depth of 2 inches. Use a chipping hammer weighing not more than 3 5 pounds. Operate the chipping hammer at a 30 – 60-degree angle to remove damaged concrete without causing additional damage and to create a rough surface for proper bonding. For Type 1 and Type 2 partial-depth repairs when using the milling machine, mill along the joint or crack. The head of the milling machine must be a “V” head, flat head, or a rounded head. When using a milling machine, square the corners of the repair area by making a saw cut to a minimum depth of 2 inches. Remove the existing concrete in the corner of the repair area using a chipping hammer weighing not more than 35 pounds. Operate the chipping hammer at a 30 – 60 degree angle to remove the concrete in the corner of the repair area. Cut and remove any reinforcement in jointed reinforced concrete pavement exposed after the removal of delaminated concrete. Do not cut or remove the reinforcement in continuously reinforced concrete pavement. Do not disturb concrete outside the limits of the repair area. If the partia l-depth repair area becomes a

full-depth concrete pavement patch because of excessive, unnecessary removal of concrete or damage to the dowel bars during the concrete removal process , construct a full -depth concrete pavement patch as specified in Section 516 at no additional cost to the Department. If dowel bars in the transverse joint are exposed and show little sign of corrosion or other damage, apply a bond breaking material to all exposed surfaces of these bars. If the Representative determines the dowel bars are unacceptable because of misalignment or extensive deterioration, construct a full-depth concrete pavement patch or corner repair as specified in Section 516. Resound the repair area in the presence of the Representative to ensure all delaminated concrete has been removed. Remove additional delaminated concrete within the repair area, but do not exceed half the slab thickness. Produce a rough surface for material bond on all edges created by sawing. Deploy the final cleaning method within 30 minutes before placing the partial -depth repair material . If using a compressed air stream, ensure it is free of oil, moisture, and other contaminants and has a minimum pressure of 100 pounds per square inch measured at the source. Re-clean areas not repaired within 30 minutes of the final cleaning.

Section 704.3 or prepare hand-batched mixtures using a p ower-driven revolving and tilting drum mixer or suitable revolving paddle mixer capable of thoroughly mixing the repair material. If using drum and paddle mixers, repair material batch sizes must be selected to fall within the minimum and maximum recommended batch size for the mixer.

install 1/2-inch expansion joint material in the joint. If the partial -depth repair abuts an existing longitudinal joint, install 1/4-inch preformed cellular polystyrene in the joint. The expansion joint material and preformed cellular polystyrene should extend at least 1/2 inch below the bottom of the repair whenever possible. If the repair material can be sawed without damage, re-establish the joint by sawing through the full depth of the repair. Seal longitudinal joints as specified in Section 512.3 and seal transverse joints as specified in Section 521.3.

bonding compound to all exposed surfaces within the repair area. Mechanically mix the grout and apply by brushing or scrubbing in a thin layer onto the concrete surface. Prepare and a pply the epoxy bonding compound according to the manufacturer’s recommendations . Do not allow the grout or epoxy bonding compound to run or puddle in low spots. Place concrete in the repair area before grout begins to dry or while epoxy bonding compound is still tacky. Remove dried grout or hardened epoxy bonding compound. Re-clean the repair area as specified in Section 525.3(c) and recoat the repair area with fresh grout or epoxy bonding compound. Place concrete if the ambient air and surface temperatures are 40F and rising. Discontinue placement of the mixture if the ambient air and surface temperatures fall below 40F. Protect repairs from freezing for a minimum of 24 hours. Consolidate the concrete u sing a spud vibrator or other acceptable method. Work concrete into saw cuts extending beyond the corners of the repair area. Strike-off and shape concrete to match the surrounding pavement, including wheel ruts. Use expansion joint material and preformed cellular polystyrene temporary forms that extend to the pavement surface to keep the concrete out of existing joints.

recommended installation temperature range and when the ambient air and surface temperatures are 40F or greater. Discontinue placement of the mixture when the ambient air and surface temperatures are outside of the manufacturer’s recommended installation range or lower than 40F. Protect repairs from freezing for a minimum of 24 hours. Use vibration or tamping to consolidate the rapid-set concrete patching material. Work concrete into saw cuts extending beyond the corners of the repair area. Strike-off and shape concrete to match the surrounding pavement, including wheel ruts. Use expansion joint material and preformed cellular polystyrene temporary forms that extend to the pavement surface to keep the concrete out of existing joints.

The return-to-service time must be considered when placing the last partial -depth repair before opening to traffic.

specified in Section 516.3(j), except use an atomizing type spray tank with an adjustable nozzle and agitate the solution before each application.

specified in Section 516.3(j). Cure test cylinders under the same conditions as the partial-depth repair. Provide insulation or heating of repair areas if the ambient air temperature drops below 80F during the curing operation. Control the curing temperature and monitor at least hourly to ensure the repair area does not experience a curing temperature change in excess of 40F within any 1 -hour period during the curing operation. If a change in curing temperature in excess of 40F occurs in the concrete pavement patch within any 1-hour period, the work will be considered defective.

Replace any completed repair areas that are delaminated, at no cost to the Department.

according to Table D.

525.4MEASUREMENT AND PAYMENT—

For the type indicated. The unit price includes removal of existing pavement and repairs or corrections as specified in Section 525.3 that are needed as a result of partial-depth repair operations.

If transverse or longitudinal joint cleaning and sealing are part of the contract, sealing of joints at partial- depth repair areas are incidental to that item and will not be payable under concrete pavement partial-depth repair.