ITEM 255 FULL DEPTH PAVEMENT REMOVAL AND RIGID REPLACEMENT

255.01 Description

255.02 Materials

255.03 Removal of Existing Pavement

255.04 Correction of Disturbed Subgrade

255.05 Placing Dowels and Tiebars

255.06 Placement of Portland Cement Concrete

255.07 Wearing Course Replacement

255.08 Opening to Traffic

255.09 Method of Measurement

255.10 Basis of Payment

255.01 Description. This work consists of full depth removal of existing pavement; removing subbase where specified; compacting the subgrade; furnishing and placing dowels, tiebars, joint sealer, and mesh where specified; placing, consolidating, finishing, and curing new portland cement concrete to the level of the existing portland cement concrete pavement; and restoring affected shoulders.

255.02 Materials. Furnish materials conforming to:

Concrete, Class C, S, FS, or MS.................................. 499

Joint sealer............................................................... 705.04

Curing materials, Type 2......................................... 705.07

Non-shrink non-metallic grout................................ 705.20

Reinforcing steel ..................................................... 709.00

Welded steel wire fabric.......................................... 709.10

Dowel bars and basket assemblies.......... 705.01 or 709.13

Expansion shield anchors Type A.......................... 712.01

Select and furnish a bond-breaker material from the approved list issued by the Laboratory.

Select and furnish grout from the approved list issued by the Laboratory that firmly anchors the dowel or tiebar within 30 minutes.

255.03 Removal of Existing Pavement. The Engineer will locate and mark all areas to be repaired before the start of diamond sawing. Provide the Engineer with aerosol spray paint to outline those areas for repair.

Saw cut the existing rigid pavement to the full depth at the limits of the area designated by the Engineer using a diamond saw blade. Where there is an existing asphalt concrete overlay on top of the concrete pavement to be removed, the Contractor may make either a full depth saw cut through the asphalt concrete overlay and the concrete pavement, or make an off-set saw cut through the asphalt concrete overlay. If making an off-set saw cut through the asphalt concrete overlay, remove the overlay as necessary to provide clearance for the full depth saw cut through the concrete pavement. The Contractor may elect to make additional cuts to facilitate the removal of the pavement.

Remove pavement in the repair area by the lift-out method without damaging or undermining the remaining pavement. After the repair area is isolated by full depth saw cuts, drill holes through the deteriorated slab, and install lift pins. Vertically lift the pavement out of the repair area. Remove loose debris left behind after lift-out using hand methods. Dispose of removed pavement according to Item 202.

Do not break the pavement and clean out the material using a backhoe unless the Engineer determines that the lift-out method is not feasible due to deteriorated pavement, existing asphalt concrete repairs, or deteriorated concrete pavement.

If the adjacent pavement or shoulder is damaged during the pavement sawing or pavement removal, make additional full depth, diamond-blade transverse and longitudinal saw cuts as necessary along the full width of the lane or lanes for a length that encompasses the damaged areas. Remove and dispose of the damaged pavement or shoulder according to Item 202.

255.04 Correction of Subgrade. After removing the existing pavement full depth and before installing dowels or tiebars, shape and recompact the subgrade to the satisfaction of the Engineer. Replace any subgrade material removed with the existing concrete pavement removal with concrete as part of the rigid pavement replacement.

255.05 Placing Dowels and Tiebars. Drill dowel and tiebar holes using hydraulic or electric drills and without spalling or damaging the existing concrete. Blow clean all drilled holes with oil free compressed air. Maintain holes dry and frost free before grouting the dowels or tiebars. Pneumatically inject grout into the rear portion of the drilled holes. Use a grout retention disc with a radius slot as shown on the plans to retain the grout within the drilled holes. Inject grout to fill all voids behind the grout retention disc and until grout extrudes through the radius slot. Insert dowels and tiebars through the grout retention disc while the disc is placed flush with the sawed edge of pavement and aligned with the drilled hole. Insertion of the dowels and tiebars shall force the grout out of the radius slot in the grout retention disc. Hold dowel bars in proper alignment until the grout has hardened.

255.06 Placement of Portland Cement Concrete. Do not place any portland cement concrete for rigid pavement replacement until the grout around the dowel or tiebar has hardened. Place portland cement concrete according to 451.06. Use forms at the shoulder. Cast each patch in one continuous operation. Consolidate the concrete around the perimeter of the patch and within the limits of the patch area using an internal type vibrator. Use approved internal type vibrators capable of visibly affecting the concrete for a distance of 12 inches (0.3 m) from the vibrator head.

Screed repairs less than 12 feet (3.7 m) in length parallel to the centerline. Screed repairs 12 feet (3.7 m) in length and longer perpendicular to the centerline.

While the concrete is still in a plastic state, test the surface for trueness and for being flush with the edges of the adjacent slabs using a 10-foot (3 m) straightedge. Place the straightedge parallel to the pavement centerline with half of the straightedge resting on the existing pavement, and draw the straightedge across the patch to test the patch edges. Check areas within the patch length in a similar manner. Where the straightedge does not remain in contact with the existing pavement while drawing it across the patch, correct all high or low areas exceeding 1/8 inch in 10 feet (3 mm in 3 m). Recheck the concrete surface after making corrections to ensure conformance to the above tolerance. Make additional checks and corrections until patch is within tolerance.

Texture the new concrete surface similar to that of the surrounding pavement.

Apply the liquid membrane-forming compound conforming to 705.07, Type 2 for curing at a minimum rate of 1 gallon (1 L) of material for each 150 square feet (3.7 m²).

Form in the plastic concrete or saw in the hardened concrete the transverse joints between the rigid pavement replacement and the existing rigid pavement. Do not allow traffic onto completed full depth repairs until the transverse joints have been widened to the specified width shown on the plans. Thoroughly clean both faces of the joint to the bottom of the proposed sealer by abrasive blasting with moisture and oil free compressed air. Clean the joint to leave a dry newly exposed concrete surface, free of dirt, dust, tar and asphalt material, curing compound, abrasive blasting material, discoloration and stain, as well as all other forms of contamination. Ensure that the top of the freshly placed sealant is 1/4 ± 1/16 inch (6 ± 2 mm) below the pavement surface and that the shape factor (depth to width ratio) of the sealant is between one and two.

255.07 Wearing Course Replacement. Replace the removed asphalt concrete overlay with Item 301 or 448 Type 2 material as shown on the plans. Apply Item 407 tack coat to the replacement surfaces.

Before opening the rigid replacement to traffic, restore the shoulders to the original line and grade using either aggregate or asphalt concrete as shown on the plans or as the Engineer directs. Fill the low areas, and compact them flush with the surrounding shoulder.

255.08 Opening to Traffic. Do not open the rigid replacement to traffic until the concrete attains a modulus of rupture of 400 pounds per square inch (2.8 MPa). If maintaining traffic in adjacent lanes, schedule work in order to place the concrete in the prepared repair area within 48 hours after removing the existing pavement. If unable to complete placement of the concrete in the exposed repair area by the end of the daily work shift, cover unfilled repair areas 10 feet (3 m) or less in length with a steel plate. Do not leave repair areas unfilled with concrete when work is suspended on weekends or holidays. If unable to complete placement of the concrete in the exposed repair area before suspending work for a weekend or holiday or within the time specified above, fill the excavation with an asphalt concrete mixture or other suitable temporary patch material with a durable surface as the Engineer directs. Maintain the temporary patches while they are in service.

255.09 Method of Measurement. 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 complete and accepted work.

The Department will measure the quantity of Full Depth Pavement Sawing by the number of feet (meters) of perimeter full depth saw cuts in the complete and accepted work. The Department will not measure off-set saw cuts. The Department will not measure additional cuts made to facilitate the removal of the pavement.

255.10 Basis of Payment. Payment is full compensation for furnishing all materials, including paint; removing pavement by any method; removing subbase for undercut replacement; compacting subbase and subgrade; placing rigid pavement, including concrete necessary to replace removed subbase or subgrade; furnishing and placing dowels, tiebars, and mesh; placing, maintaining, removing, and disposing of temporary patches, and restoring the shoulders.

The Department will not pay for additional concrete sawing and removal depths within 1 inch (25 mm) greater than those shown on the plans.

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.

The Department will pay for accepted quantities at the contract prices as follows:

Item unit Description

255 Square Yard Full Depth Pavement Removal
(Square Meter) and Rigid Replacement, Class ___
255 Foot (Meter) Full Depth Pavement Sawing