263 SECTION 506 CONCRETE PAVEMENT REPAIR
506.1 -DESCRIPTION : This work consists of the removal and replacement of deteriorated concrete pavement and patches, and replacing subbase material where required, at locations as shown on plans or as specified by the Engineer. The following is a description of each patch type:
Patching shall consist of full depth, full lane width concrete pavement repairs equal to or greater than four ( 4) feet in length. Type I patches shall constructed in accordance with the Concrete Repair Details in the plans. ii. Jointed Concrete Pavement Patch, Type II: Patching shall consist of partial depth concrete pavement repairs that extend a minimum of two ( 2) inches and no deeper than one -half the slab thickness at cracks or no more than one -third the slab thickness at doweled joints. Type II patches shall be constructed in accordance with the Concrete Repair Details in the plans. iii. Jointed Concrete Pavement Patch, Type III: Patching shall consist of a repair along the edge of a transverse crack or joint that extends from the bottom of a partial depth repair (Type II) to potentially the full depth of the slab, and isolated within twelve ( 12) inches of either the longitudinal joint or pavement edge. Type III patches shall be constructed in accordance with the C oncrete Repair Details in the plans.
506.2 -MATERIALS : Materials shall meet the requirements of section 501 or 601, and as follows:
MATERIAL SECTION OR SUBSECTION Accelerating Admixtures 707.13 Curing Materials 707.6 -707.10 Epoxy -Coated Dowel Bars 709.15 Joint Sealer 708.3, 708.4 Portland Cement Concrete 501 or 601 Subbase 307 Tie Bars and Hook Bolts 709.1
A non -shrink cementitious grout meeting the requirements of ASTM C1107 or an approved epoxy adhesive meeting the requirements of AASHTO M 235, Type IV, Grade 3, Class B or C shall be used to firmly anchor dowel bars in 30 minutes. This material shall be approved by the Engineer for the intended application. Cement meeting the requirements of ASTM C150, Type III may be used in the concrete mixes for concrete pavement repair.
506.3 -PROPORTIONING : Portland cement concrete for patching concrete pavement shall meet the requirements of shown by compressive strength tests, in the approved mix design, that th e concrete mix shall attain
264 2,000 psi prior to the time at which the pavement will be opened to traffic. Also, the maximum water -cement ratio (w/c) shall be 0.44, and an AASHTO number 8 (No. 8) coarse aggregate shall be required in Type II repairs with a depth of three ( 3) inches or less. Type III repairs may be placed simultaneously with Type II repairs. When constructed in this manner, the same concrete mix shall be used in both repair types . Prior to the start of work, the Contractor shall submit the mix proportions and recent compressive strength test data for the specified age at which the concrete is to be opened to traffic.
506.4 -TESTING : All testing shall be in accordance with section 501. The Contractor shall fabricate a minimum of nine compressive strength cylinders for each 24 -hour period of operation. Six of these nine field cured cylinders shall be field cured in a temperature and moisture condition as close as possible to that of the concrete in the repair area. When the concrete in the repair area must attain the compressive strength, required to open it to traffic in less than 8 hours, the cylinders which represent that concrete shall be cured in a curing device which automatically maintains the curing temperature and duplicates the temperature of the in -place concrete that the cylinders represent. When the average strength of three of these cylinders, representing the concrete p laced, indicate that the concrete has attained the required strength for opening to traffic, that concrete may be put into service. These cylinders shall represent concrete produced from the batch from which they were fabricated and, if applicable, concre te from previous batches also. These cylinders will not represent any concrete which was placed after the time that they were fabricated. Three of the nine cylinders shall receive standard curing and shall be tested at 28 days to verify that the required strength at that age has been achieved. In lieu of six field cured cylinders required above, the Contractor may use the Maturity Method for the Estimation of concrete strength, as outlined in MP 601.04.21 for determining when the pavement may be opened to traffic.
506.5 -EQUIPMENT AND TOOLS : Equipment and tools shall be in accordance with section 501 unless noted otherwise. Saw cutting equipment shall be capable of sawing neat vertical faces alon g the patch boundaries. The use of a carbide -toothed wheel saw shall not be permitted for sawing the patch boundaries. A carbide -tipped wheel saw may be used for additional saw cuts provided that a minimum three (3) inch clearance from the sawed boundary is maintained. Gang drills shall be used to drill multiple dowel bar holes simultaneously for Type I repairs. The drilling equipment shall firmly hold the drill bits in a horizontal position at the correct height and prevent them from wandering. The dri lling equipment shall maintain holes with consistent diameters. Drilling equipment which damages existing concrete or causes the holes to exceed the specified diameter due to movement, bouncing, wobbling, etc. shall not be used. Drilling operations shall be stopped if the drilling equipment is deemed to be inadequate by the Engineer, and drilling operations shall not be resumed until adequate drilling equipment is used.
506.6 -CONSTRUCTION METHODS : 506.6.1 -Removal of Existing Pavement: Designated defective pavement shall be removed full depth, and undisturbed portions of the existing pavement adjacent to the area to be patched shall be left with straight vertical sides. The existing pavement to be removed shall be sawed full depth along the transverse and longitudinal boundaries, including the lane and shoulder/lane joints as shown on the plans or