7-21 720-10 Measurem Ent and Payment
A.General Concrete Shoulders Adjacent to __" Pavement will be measured and paid as the actual number of square yards of shoulders completed and accepted. In measuring this quantity, the width of the shoulders will be as called for on the pla ns or as directed by the Engineer. The length will be the actual length constructed, measured along the surface of the shoulders at the centerline of each shoulder.
B.Shoulder Deficient in Thickness Pay factors are determined in accordance with Subarticle 7 10-10(B). When the shoulder is deficient in thickness by more than 1 inch, the Engineer will determine if the shoulder can be left in place or be removed and replaced. Where the Engineer determines the shoulder can be left in place, the shoulder will be accepted at a reduced unit price not to exceed 50% as provided in Article 105- 3.
C.Concrete Shoulder Varying In Strength Concrete shoulders shall meet the strength requir ements of Subarticle 710- 10(C). The quantities of concrete shoulder that fail to meet 4, 500 psi, measured as provided in
Article 710 — 10, will be paid for at an adjusted unit price per square yard completed in
place and accepted. The adjusted contract unit price will be determined by multiplying the contract unit price by the pay factor level in Subarticle 710 -10(C). Where concrete shoulder deficient in strength is removed and replaced, the replacement pavement, if acceptable, will be paid at the contract unit price for Concrete Shoulders Adjacent to __" Pavement , which price and payment will be full compensation for all work of placement, removal and replacement.
D.Multiple Adjustments in Price Concrete shoulder found deficient in both thickness and strength will be evaluated by the Engineer to determine if it may be permitted to re main in place. Concrete shoulder permitted to remain in place will be paid at a reduced price determined by successively multiplying the contract price by the appropriate factor indicated for each deficiency.
E.Pay Items Payment will be made under: Pay Ite m Pay Unit Concrete Shoulders Adjacent to __" Pavement Square Yard
723-1 Description
Perform work covered by this section, including, patching concrete pavement spalls and repair of jointed concrete pavement slabs using very high early strength concrete. Patch partial and full depth spalls in existing Portland cement concrete pavement by sawing and removing the broken, damaged or disintegrated concrete pavement from the spalled areas of the pavement surface and patch the areas with an approved patching material. Alternate methods and materials for patching concrete spalls may be submitt ed by the Contractor for approval by the Engineer. Remove and satisfactory dispose of existing damaged jointed concrete pavement slabs, furnish and place new jointed concrete pavement slabs as shown in the plans or directed by the Engineer.
7-22 723-2 Materials
Refer to Divisions 6, 7 and 10. Item Section Curing Material s 1026 Dowels and Tie Bars 1070 -6 Geotextile for Soil Stabilization 270 Joint Filler 1028 -1 Low Modulus Silicone Sealant 1028 -3 Portland Cement Concrete 1000 Select Material, Class IV 1016 Water 1024 -4 For repair of jointed concrete pavement slabs, use Select Material, Class IV. If Select Material, Class IV does not meet the requirements of Section 1016 , the Engineer may consider the material reasonable acceptable in accordance with Article 105 -3. Patch ing material shall be mixed and installed, handled and stored, and cured in accordance with the manufacturer’s instructions. The Contractor may, at his option, use any approved material from the NCDOT APL or an approved equal as per the Engineer.
723-3 Methods of Production
A.Repair of Jointed Concrete Pavement Slabs Repair the slabs in accordance with Section 700. The concrete shall meet the requirements of Article 723 -4. Repair of the slabs shall be conducted in one lane at a time and be accomplished with other operations in progress in the same area. For all cases of slab removal, remove the entire 12 feet width and a minimum of 6 feet in the travel direction. Any remaining portion of a slab that is removed shall not be less than 6 feet in the travel direction. As a result of the full depth sawing of the existing pavement to remove the distressed area, saw cuts that extend into the adjacent pavement shall be filled with epoxy prior to placing traffic on the new area. The epoxy shall meet the requirements of Section 1081, Type 3. Take necessary measu res to protect the exposed subgrade and base form damage resulting from surface water or rain during the period between the pavement removal and replacement. The Contractor shall submit his plan for removing the pavement areas to the Engineer for approval . The removal method shall minimize damage to t he subgrade and to adjacent pavement and shoulders. At locations as directed by the Engineer, the Contractor shall:
1.Remove unsuitable aggregate base material and backfill with Select Material, Class IV as dir ected by the Engineer; or
2.Remove unsuitable aggregate base material, undercut the subgrade, place Geotextile for Soil Stabilization per Section 270, and backfill with Select Material, Class IV as directed by the Engineer. Thoroughly tamp any loosened subg rade or base material to the satisfaction of the Engineer before the pavement is replaced. New pavement shall be cast to match the thickness of the adjacent slabs. Pneumatic or hydraulic drills and bits that will drill a hole in the existing concrete face s for placement of the dowels at location specified on the p lans shall be used. The equipment shall be operated so as to prevent damage to the pavement being drilled. The
7-23 drilling procedure shall be approved by the Engineer. The drilled holes shall be
thoroughly cleaned of all contaminants and the dowels of specified type and size shall then be set into the hardened concrete face of the existing pavement with an epoxy bonding compound meeting the requirements of a Type 3A epoxy detailed in Section 4 1081. The specified dowels shall be placed at locations noted on p lan details with one - half of dowel protruding beyond the hardened face of existing pavement and placed at correct horizontal and vertical alignment with misalignment not to exceed 0.4 inches in the vertical or oblique plane. The epoxy shall be allowed to harden sufficiently prior to placing concrete to prevent any movement of the dowels during the placement of the concrete. A sufficient amount of epoxy must be placed in the back of the hole so t hat the entire cavity around the dowel is completely filled upon insertion of the dowel bars. Any excess epoxy shall be removed. The epoxy adhesive must be packaged in a cartridge with a mixing nozzle that thoroughly mixes the two components as they are dispensed (the mixing nozzle must be a minimum of 8 inches long) or may be placed with a machine which mixes the two components thoroughly and to the proper ratio as the material is being placed. Use dowels of the type, size, spacing, and at the location s pecified in the Roadway Standard Drawing. At no time shall dowels be driven into a dowel hole with sledge hammers or other devices. In all cases, any dowel which cannot be freely inserted into a dowel hole will be rejected for use. Prior to placing concr ete, the vertical exposed faces of the existing slabs shall be thoroughly cleaned of contaminates using wire brushing or other methods approved by the Engineer. Extra care must be taken to remove all existing silicone or other joint sealant from the expos ed concrete faces. The concrete shall be deposited within the slab replacement area in such manner as to require as little re -handing as possible, to prevent segregation of the mix. Hand spreading shall be minimized as much as possible, but where necessar y, shall be done with shovels, not rakes. Workers will not be allowed to walk in the fresh concrete with shoes coated with earth or other foreign substances. The replaced slab area shall be filled with concrete and thoroughly consolidated by rodding, spa ding, and sufficient vibration to form a dense homogeneous mass throughout the area. The final surface area shall be uniform in appearance and free of irregularities and porous areas. The finished surface, including joints, shall meet a surface tolerance of 1/8 inch in 10 feet in any direction. Any necessary corrections shall be done by grinding. Any replaced slab which is low in relation to adjacent slabs may be ordered replaced by the Engineer. Replacement of such a slab would generally be r equired if, in the opinion of the Engineer, excessive grinding of the adjacent pavement is necessary to match the profile of the full depth slab replacement or if a drainage problem would be created by grinding the adjacent pavement. The surface finish of the proposed concrete pavement shall be a burlap drag finish and conform to the cross -section of adjacent pavement. The method of finishing shall be approved by the Engineer. Immediately after finishing operations have been completed and surface water has disappeared, all exposed surfaces of the pavement shall be cured in accordance with the applicable provisions of Section 700- 9 and Section 1026.
B.Patching Concrete Pavement Spalls When the Contractor is working under a lane closure, concrete patching operations shall be conducted in one lane at a time or as directed by the Engineer. The work shall be accomplished with other operations in progress within the same area. Clean surfaces within the repair area free of oil, dust, dirt, deteriorated concrete and other contaminates immediately before placement of the epoxy and patching material. Apply epoxy to the vertical and flat surface of the cleaned spall areas prior to placing concr ete.
7-24 The pavement shall not be opened to traffic until the concrete is appropriately cured per
the manufacturer’s recommendations.
723-4 Very High Early Strength Concrete for Concrete Pavement Repair
Submit mix designs for Very High Early Strength Concrete for Concrete Pavement Repair in terms of saturated surface dry weights on Materials & Tests Form 312U for acceptance at least 30 days before proposed use. Mix designs shall meet the design requirements provided in Article 1000 -5 and Table 1000 -7 for Very High Early Strength Concrete for Concrete Pavement Repair . Design and produce a concrete mix that can produce 400 psi flexural strength in approximately 4 hours . The timing of the addition of hydration control admixtures is critical to the performance of this concrete; therefore, an admixture representative shall be present on the job when Very High Early Strength Concrete is batched. With permission of the Engineer, compressive strength testing and mat urity testing may be used in lieu of or concurrent with flexural strength testing to determine the acceptability of the concrete in the field.
723-5 Measurement and Payment
The quantity of Repair of Jointed Concrete Pavement Slab to be paid for at the unit price established herein will be the actual number of square yards of jointed concrete pavement with dowels which has been completed and accepted. In measuring this quanti ty, the width of the repair will be measured perpendicular to the centerline of the lane. The length will be the actual length constructed, measured along the centerline of the pavement. The unit price for Repair of Jointed Concrete Pavement Slabs will be full compensation for all work covered including furnishing all labor, materials, tools, equipment, and incidentals for doing all work involved in placement of the concrete including but not limited to furnishing placing, and curing concrete; dowel bars; sawing and removing concrete; and filling saw cuts around the pavement repair. The quantity of Select Material, Class IV to be paid for at the unit price established herein will be the actual number of tons of aggregate which has been incorporated into the completed and accepted work. The aggregate will be measured by being weighed in trucks on certified platform scales or other certified weighing devices. No deductions will be made for any moisture contained in the aggregate at the time of weighing. The unit price for Select Material, Class IV will be full compensation for all work including but not limited to , removing of existing aggregate base course and backfilling with Select Material, Class IV. The quantity of material removed from beneath the base course as Undercut Excavation will be measured and paid for in accordance with Article 225-7. The quantity of Geotextile for Soil Stabilization furnished and placed as directed by the Engineer will be measured and paid for in accordance with Article 270-4. Patching Concrete Pavement Spalls to be paid will be the actual number of square feet of existing concrete which has been patched and accepted. The actual length and width of each completed patch will be measured along the surface of the patch. The pric e and payment w ill be full compensation for work involved including furnishing labor, materials, tools, equipment and incidentals for sawing concrete pavement, removing deteriorated concrete, cleaning surfaces, epoxying, furnishing, placing, finishing, and curing concrete patch.
Source: North Carolina Standard Specifications for Roads and Structures, 2024 Edition. Pages 331–334 of 857.