506Concrete 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 Concrete 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 the concrete mix shall attain 263 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 placed, 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 along 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 264 as directed by the Engineer. Additional saw cuts inside the patch boundaries will be permitted to facilitate the concrete removal operation. Concrete sawn full depth to be removed shall be lifted out by means of chains, lift-pins, or other approved devices. The breaking of concrete in-place shall not be permitted. During the removal operations, utmost care shall be exercised to minimize disturbance and damage to the base material, and the adjacent pavement and shoulder. 506.6.2-Conditioning Existing Subbase: Prior to placing concrete in the repair area, any subbase material that is disturbed below the desired level of cleanout shall be removed and the patch area compacted to the satisfaction of the Engineer. Unsuitable subbase material, concrete, reinforcing steel, and any other debris shall become property of the Contractor and shall be leg ally disposed. The Contractor shall replace the removed subbase material with concrete integral to pavement replacement. If more than an additional one (1) inch of concrete is needed to replace subbase or subgrade material, then the additional volume of concrete, required to fill the excavated area up to the elevation of the bottom of the existing pavement, shall be paid for by the cubic yard as a separate pay item. 506.6.3-Placing Concrete: Unless behind permanent closures or unless otherwise approved by the Engineer, all excavated areas shall be patched the same day that they are excavated. The excavated area shall be thoroughly cleaned of loose material and debris and moistened prior to the placement of concrete. Existing pavements shall not be removed if such removal will result in concrete being placed when the ambient air temperature is below 32 °F, unless approved by the Engineer. Concrete for partial depth repairs shall not be placed when the ambient temperature is below 40°F. The concrete temperature at the time of placement shall not be less than 70 °F and not more than 95°F, unless approved by the Engineer. Concrete shall be deposited in the excavated area, and the free fal l shall not be more than three (3) feet. If the concrete does not fall into its final position in the patch, it shall be moved by means of shovels; raking is prohibited. The concrete shall be worked with tampers, spades, or other tools to completely fill the patch area. Maximum effort will be used to ensure that the area beneath the existing concrete pavement is completely filled. Internal vibration shall be used. Following the placing of the concrete, the surface will be struck off to a finished grade and floated to a smooth finish. Finishing of the plastic concrete shall conform to the requirements of Section 501.12 of the Specifications, except that the final concrete surface shall be textured similar to that of the adjoining pavement. 506.6.4-Straightedge Checking and Surface Correction: During finishing operations, deviations in adjacent lanes which are also to be repaired shall not be transferred to the new construction. The Contractor shall furnish and use straightedges to check the surface tolerance. For patches ten (10) feet or more in length, a ten (10) foot straightedge shall be used. Shorter straightedges shall be used for patches less than ten (10) feet in length. The minimum length straightedge shall be six ( 6) feet. Section 50 1.12.6 shall govern except that the shorter straightedges shall be used for shorter patches. 506.6.5-Curing: Immediately after straight edging and texturing, the concrete shall be cured in accordance with Section 501.14. Where early opening to traffic is required, insulation 265 mats or blankets may be used over the repairs during curing in order to accelerate strength gain. 506.6.6-Sealing Joints: When patching two lanes simultaneously, the longitudinal joint shall be reestablished by sawing. Joint sealing shall be done in accordance with Section 510. 506.6.7-Repair of Adjacent Shoulders: Within 24 hours after completion of a patch area, any adjacent shoulders damaged during pavement repair operations shall be reconstructed in accordance with the requirements of the applicable section of the specifications to match the finished shoulder grade and to the satisfaction of the Engineer. In the event traffic is to be permitted on the patch area prior to reconstruction of the shoulder, the Contractor sh all first make such temporary repair to the shoulder as is necessary to avoid any hazardous condition. 506.6.8-Specific Construction Methods: Construction methods specific to each repair type are noted in the following sections. 506.6.8.1-Type I Repairs: Where the existing joint dowel assembly is to be removed, the existing concrete shall be sawcut full depth and removed a minimum of one (1) foot on either side of existing transverse joints. Minimum length of removal shall be four (4) feet in accordance with that shown in the WVDOH Concrete Repair Details. Multiple repairs shall be combined to make one large patch if the edges of adjacent repairs, in the same lane, are less than ten (10) feet apart. Oversawing into the adjacent slabs or shoulder shall be kept to the minimum amount necessary to ensure that full depth cuts in the corners have been achieved. All oversawing shall be cleaned and filled with an approved joint sealing material meeting the requirements of Section 708.3. Any areas damaged during concrete sawing and removal operations shall be repaired to the satisfaction of the Engineer by extending the patch boundary or repairing spalls at the Contractor’s expense. Spalls greater than ¼ inch wide and two (2) inches long and more than ½ inch deep below the pavement surface shall be repaired using an approved epoxy mortar. The patch boundary shall be extended by re -sawing the limits of the patch beyond the spalled area when spalls greater than one (1) inch wide and twelve (12) inches long and more than ½ inch deep below the pavement surface are created by the pavement removal operation. A bond breaking material, approved by the Engineer, shall be placed at the longitudinal joint for Type I patches as shown in WVDOH Concrete Repair Details. Acceptable bond - breaking materials include white pigmented curing compound, roofing felt, and tar paper. Where dowels are required, holes slightly larger than the diameter of the dowels shall be drilled nine ( 9) inches into the face of the existing slab starting six ( 6) – twelve (12) inches from either edge and then on twelve (12) inch centers. Hole diameters shall be 1⁄16 inch Larger than the dowel bar diameter when using epoxy material to anchor the dowels, and h ole diameters shall be 0.20 to 0.25 in ch Larger than the dowel bar diameter using when cementitious grout to anchor the dowels. The number of dowels per joint shall be as shown in the WVDOH Concrete Repair Details. The holes shall be located at a depth as shown in the WVDOH Concrete Repair Details. The dowels shall be carefully aligned (within ¼ inch over a 1-foot length) with the direction of the pavement and parallel to the plane of the surface. The drilled holes shall be thoroughly cleaned with compressed 266 air to remove all dust, dirt, loose material and moisture. An approved quick setting, non- shrinking cementitious grout or epoxy adhesive shall be used to anchor the dowels in the holes. Before installing dowels, place the anchoring material (cementitious grout or epoxy adhesive) in the back of each hole. This ensures that the anchoring material flows out around each bar, fully encasing it. Do not coat one end of the bar with anchoring material and then insert the bar into the hole – the air pressur e inside the hole will force the anchoring material back out of the hole, leaving a void around the bar. Dipping of the dowels into the anchoring material (cementitious or epoxy), prior to insertion into the holes, is not permitted. The holes shall be fi lled from the back to the front with the anchoring material prior to insertion of the dowel. The anchoring material shall be put into the hole in sufficient quantity so that when the bar is inserted, the anchoring material completely fills the annular space around the dowel. Rotate the dowel bar one full revolution while inserting it into the hole. The holes shall be completely filled with the anchoring material around the dowels so as to minimize vertical movement of the dowels and ensure that the dowels are permanently fastened to the existing concrete. A grout retention ring shall be used around all dowels, as shown in the WVDOH Concrete Repair Details. The end of the bar that extends into the repair area should have a bond breaker applied to it to p revent bonding with the patch material. This bond breaker may be applied at the manufacturer or field applied. After installation, the vertical and horizontal skewness of the dowels shall be checked. If more than 3 dowels per joint are misaligned by more than 3/16-inch over a nine (9) inch length, the repair boundary shall be re -sawed one (1) foot back from the existing repair boundary, and dowels shall be re-installed. Type I patches less than six (6) feet in length shall require 2 -#4 rebar placed tran sversely as noted in the Standard Detail. This work shall be done at the Contractor’s expense. The surface edges of all patches shall be tooled, formed and/or sawed, and cleaned to result in a properly dimensioned reservoir for sealant. All transverse and longitudinal joints at pavement repair locations shall be sealed in accordance with manufacturer’s recommendations unless otherwise approved by the Engineer. 506.6.8.2-Type II Repairs: Full lane-width partial depth repairs at transverse joints and cracks and at longitudinal joints twelve (12) feet or more in length shall be a minimum of eighteen (18) inches wide, with the vertical face of the repair being no less than six (6) inches from the crack or the joint. Partial depth repairs shall be sawed a minimum depth of two (2) inches around the perimeter of the patch area to provide a vertical face at the edges unless removal is to be performed with milling operations. Acceptable milling operations shall provide neat vertical faces and be approved by the Engineer. Concrete within the patching area shall be broken out with a pneumatic hammer not heavier than a 35-pound class or by other methods approved by the Engineer. Edge spalls greater than ¼ inch wide and two (2) inches long and more than ½ inch deep below the pavement surface shall be repaired using an approved epoxy mortar. The patch boundary shall be extended by re -sawing the limits of the patch beyond the spalled area when spalls greater than one (1) inch wide and twelve ( 12) inches long and more than ½ inch deep below the pavement surface are created by the pavement removal operation. The area of failure shall be removed by equipment that will not damage the adjacent sound pavement. The exposed faces of the concrete shall be free of loose particles, oil, dust, and other contaminants before placement of patch material. Immediately prior to placement of the concrete patch, all exposed concrete faces within the patched area shall 267 be cleaned by sandblasting, then airblasting, then coated with an approved epoxy bonding compound per the manufacturer’s recommendations. All residues shall be removed just prior to placement of the concrete bonding agent. The fresh concrete shall be placed in the repair area while the epoxy bonding compound is still tacky. If the epoxy bonding compound is no longer tacky immediately prior to placement of the fresh concrete, then all surface contaminants shall be removed, and another coat of epoxy bonding compound shall be reapplied. Any crack or joint within the limits of, or adjacent to, the partial depth repair shall be re-established by forming with an acceptable material in order to follow the crack or joint alignment. The method and mat erial used to re -establish the crack or joint shall be approved by the Engineer. However, at joint repairs, sawcutting through the full -depth of the repair area may be used to fully re-establish the joint being repaired. Additionally, the Contractor shall saw and seal existing joints and cracks, involving partial depth repairs, in accordance with Section 510. 506.6.8.3-Type III Repairs: “Turned Down Edge” repairs at transverse joints and cracks shall extend no more than twelve (12) inches into the slab from the edge of pavement whether at the outside or along an interior longitudinal joint. Concrete within the patching area shall be broken out with a pneumatic hammer not heavier than a 35-pound class or by other methods approved by the Engineer. The a rea of failure shall be removed by equipment that will not damage the adjacent sound pavement. Number 4 tie bars, ten (10) inches in length, shall be inserted into the exposed vertical faces within the repair area. One bar shall be placed per one -foot of exposed face, or fraction thereof, on each side of the transverse crack or joint. The bar(s) shall be inserted at mid-depth of the slab, allowing for five (5) inches of length to extend into the area to be repaired. The hole(s) for placement of the tie bar(s) into the exposed vertical face of the slab shall be slightly larger than the diameter of the bar and shall be drilled at an angle in order to allow for drill clearance. Hole diameters shall be 1⁄16 inches Larger than the bar diameter when using epoxy material to anchor the bars, and hole diameters shall be 0.20 to 0.25 inches Larger than the bar diameter using when cementitious grout to anchor the bars. Additionally, a minimum clearance of one (1) inch shall be maintained around the hole for placement of concrete. The drilled holes shall be thoroughly cleaned with compressed air to remove all dust, dirt, loose material and moisture. An approved quick setting, non - shrinking cementitious grout or epoxy adhesive shall be used to anchor the bars in th e holes. Before installing bars, place the anchoring material (cementitious grout or epoxy adhesive) in the back of each hole. This ensures that the anchoring material flows out around each bar, fully encasing it. Do not coat one end of the bar with anchoring material and then insert the bar into the hole – the air pressure inside the hole will force the anchoring material back out of the hole, leaving a void around the bar. Dipping of the bars into the anchoring material (cementitious or epoxy), prior to insertion into the hole is not permitted. The holes shall be filled from the back to the front with epoxy or grout prior to insertion of the bar. The anchoring material shall be put into the hole in sufficient quantity so that when the bar is inserted , the anchoring material completely fills the annular space around the bar. Rotate the bar one full revolution while inserting it into the hole. The holes shall be completely filled with the anchoring material around the bars so as to minimize vertical movement of the bars and ensure that the bars are permanently fastened to the existing concrete. The bar should be bent prior to insertion into the grouted hole such that the exposed portion of the bar within the area being repaired shall be parallel with the 268 pavement surface. No bars shall be placed in a manner that would interfere with free movement of the joint or crack being repaired and re-established. The exposed faces of the concrete shall be free of loose particles, oil, dust, and other contaminants before placement of patch material. Immediately prior to placement of the concrete patch, all exposed concrete faces within the patched area shall be cleaned by sandblasting, then airblasting, then coated with an approved epoxy bonding compound per the manufacturer’s recommendations. All residues shall be removed just prior to placement of the concrete bonding agent. The fresh concrete shall be placed in the repair area while the epoxy bonding compound is still tacky. If the epoxy bonding compound i s no longer tacky immediately prior to placement of the fresh concrete, then all surface contaminants shall be removed, and another coat of epoxy bonding compound shall be reapplied. Any crack or joint within the limits of, or adjacent to, the repair shall be re-established by forming with an acceptable material in order to follow the crack or joint alignment. However, at joint repairs, sawcutting through the full-depth of the repair area may be used to fully re-establish the joint being repaired. The me thod and material used to re-establish the crack or joint shall be approved by the Engineer. Additionally, the Contractor shall saw and seal existing joints and cracks, involving partial depth repairs, in accordance with Section 510. 506.7-RIDE ACCEPTANCE: As soon as the concrete has hardened sufficiently, the pavement surface shall be tested with a ten (10) foot straightedge. The straightedge shall be placed in successive positions parallel to the road centerline, matching existing wheel paths. Areas showing deviations (either high or low) of more than ¼ inch in ten (10) feet shall be marked and corrected down with approved grinding equipment to an elevation where the surface deviations will not be more than ¼ inch in ten (10) feet. All joint sealing operations shall be performed after any grinding operations. In the event that the deviation cannot be corrected to ¼ inch or less (either high or low) in ten (10) feet, the areas shall be removed and replaced at the discretion of the Engineer and at the Contractor’s expense. All areas or sections so removed shall not be less than six (6) feet in length or less than full width of the traffic lane involved. Any remaining portion of the slab adjacent to the joints that is less than six (6) feet in length shall also be removed and replaced. Where concrete repairs are made that are to be overlayed, the smoothness criteria is waived for the concrete repair. 506.8-METHOD OF MEASUREMENT: The quantity of concrete pavement repair to be paid for will be the number of square yards complete in place and accepted for all Type I and Type II repairs. Additional concrete required to fill the excavated area up to the elevation of the bottom of the existing pavement for Type I repairs, as outlined in Section 506.6.2, shall be paid for by the cubic yard. For Type III repairs, each location complete in place and accepted will be paid for. 506.9-BASIS OF PAYMENT: The quantity of concrete pavement repair, determined as provided above, will be paid for at the contract unit price and shall constitute full compensation for the furnishing, hauling, and placing of all materials, saw cutting pavement to the required depth, the removal and disposal of old concrete, preparing of sublayer, furnishing and installing steel dowels, furnishing and installing reinforcing steel as specified, furnishing, placing, finishing, and curing the concrete, cleaning and 269 sealing joints, patch area protection, and for all other materials, labor, tools, equipment, and incidentals necessary to complete the item.

506.10PAY ITEMS:

ITEM DESCRIPTION UNIT 506001-003 Concrete Pavement Repair, Type I, “thickness” Square Yard 506001-004 Concrete Pavement Repair, Type II Square Yard 506001-005 Concrete Pavement Repair, Type III Each 506003-* Additional Concrete for Type I Repair Cubic Yard * Sequence number “thickness” shall be in inches 270