for Highway Construction Page 450 of 71 5 SECTION 581 – CONCRETE CRACK REPAIR
581.01 Description.
A.Preparation. Prepare concrete surface cracks to inject with an epoxy resin adhesive. Repair cracks wider than 0.016 inch measured at the concrete surface including the finishing and cleaning of girders, pier caps, columns, and abutments as specified and as directed.
B.Injection. Inject epoxy resin adhesive into prepared concrete cracks.
581.02 Materials.
A.Preparation. Use the following material to prepare the cracks for injection: Epoxy Resin for Surface Sealing. Provide a troweling -grade epoxy paste adhesive conforming to ASTM C881, Type I, Grade 3, Class B and C for the surface seal material capable of being applied to vertical and overhead surfaces and capable to confine the injection adhesive in the cracks during injection and curing . Ensure the surface seal material has adequate strength to hold injection fittings firmly in place and to resist injection pressures adequately to prevent leakage during injection. The Department will not allow material that contains asbestos. Ensure properties meet Table 581.02- 1. Table 581.02 -1 – Epoxy Resin Properties for Surface Sealing Property Requirement Test Method Tensile Strength ≥ 3,000 psi at 14 days ASTM D638 Flexural Strength (Modulus of Rupture) ≥ 3,700 psi at 14 days ASTM D790 Total Water Absorption 1.0% max at 7 days ASTM D570 (2 -hour boil) Bond Strength – dry cure ≥ 1,500 psi at 2 days ASTM C882 hardened con crete to hardened concrete Bond Strength – moist cure ≥ 1,500 psi at 14 days ASTM C882 hardened concrete to hardened concrete
B.Injection. Use the following material for injection: Epoxy Resi n for Injection. Provide epoxy adhesive for crack injection as an epoxy resin, 2- component, low viscosity adhesive containing no solvents or nonreactive dilutives conforming to ASTM C881, Type I and IV, Grade 1, Class B and C. Ensure properties meet Table 581.02 -2. for Highway Construction Page 451 of 71 5 Table 581.02-2 – Epoxy Resin Properties for Injection Property Requirement Test Method Tensile Strength ≥ 7,000 psi at 14 days ASTM D638 Initial Viscosity > 150 to <450 centipoise ASTM D2393, Brookfield RVT Spindle No. 2 at 100 rpm Flexural Strength (Modulus of Rupture) ≥ 1200 psi at 14 days ASTM D790 Total Water Absorption 1.5% max at 7 days ASTM D570 ( 2 hour boil) Bond Strength – dry cure ≥ 1500 psi at 2 days ASTM C882 hardened concrete to hardened concrete Bond Strength – moist cure ≥ 1500 psi at 14 days ASTM C882 hardened concrete to hardened concrete
581.03 Construction Requirements.
A.Preparation.
1.General. Apply epoxy resin adhesive for surface sealing in accordance with the manufacturer's written instructions. Provide injection ports along the crack at intervals less than the thickness of the member. Set entry ports in accordance with epoxy injection material manufacturer's written instructions. Apply surface seal material to the surface of the crack and adjacent areas of application between the injection ports as needed. Drill port holes using a hollow core drill bit with a vacuum retention sy stem for de bris removal or otherwise cleaned out before injecting. Drill holes to at least ⅝ inch depth and recess the ports at least ½ inch with a ⅛ inch reservoir at the bottom of the port. For cracks open on both sides of the member, provide porting devices on opp osite sides at staggered elevations when practical. Apply an adequate seal and allow sufficient time for the surface seal material to gain adequate strength to prevent the escape of the epoxy resin adhesive for the injection grouting.
2.Preparation. The Engineer will mark all areas and cracks that require repair. Clean cracks and adjacent application surfaces to remove loose concrete, dirt, dust, grease, oil, efflorescence, or other foreign matter detrimental to the epoxy injection bond and surface seal system. The Department will not allow acids and corrosives for cleaning. Pressure point spacing depends on size and overall area thickness containing cracks.
3.Finishing. When the cracks are filled, allow the epoxy adhesive to cure for sufficient time to allow surface seal removal without draining or run back of the epoxy material from cracks. Remove surface seal material and injection adhesive runs or spills from the surfaces. Finish surface area flush to the adjacent concrete showing no indentations or protrusions caused by the entry ports placement and blend with the existing concrete surface. for Highway Construction Page 452 of 715 B. Injection.
1.General. Apply epoxy resin adhesive for injection in accordance with manufacturer's written instructions.
2.Equipment. Inject 2- component, epoxy resin adhesive using a positive displacement pump equipped to control exact proportions with a nozzle- mounted interlock . Provide electric or air - powered pumps and an in- line mixing and metering system. Ensure automatic pressure- control injection equipment is capable of dischar ging the mixed adhesive at any pre- set pressure up to 200 psi. Ensure equipment is capable of maintaining the volume ratio for the injection adhesive prescribed by the adhesive manufacturer within a tolerance of 5 percent by volume at any discharge pressure up to 200 psi. Provide injection equipment with auto- stop senso rs on both A and B component reservoirs that will stop the machine when only 1 component is being pumped to the mixing head. Test equipment after every 4 hour s of use and at the beginning of each shift for the proper injection ratio of compo nents. Disconnect the injection mixing head equipment and pump the 2 adhesive components simultaneously through the ratio check device. Control backpressure i n the ratio check device with 2 independent valve nozzles by opening or closing the valve. Provide a pressure gauge for sensing the backpressure behind each valve. Adjust the discharge pressure to 160 psi for both adhesive components. Simultaneously discharge both adhesive components into separate calibrated containers then compare the amounts discharged to determine if they are within the manufacturer's recommended ratio for the appropriate material. Keep complete and accurate pressure and ratio test recor ds and make them available to the Engineer.
3.Execution. Spacing of pressure points d epends on size and overall thickness of area containing cracks. Start injection work at the lowest point and continue pumping until there is an appearance of epoxy adhesive at the next adjacent entry port. When epoxy adhesive travel is indicated by appearance at the next adjacent port, discontinue injection on the entry port being pumped and transfer epoxy injection to next adjacent port where epoxy adhesive has appeared. Completely fill cracks by continuous epoxy adhesive injection. If port -to-port epoxy adhesive travel is not evident, stop work immediately and notify the Engineer. The Engineer may require the Contractor to core the injected areas to confirm ful l crack penetration. Rectify areas not receiving full penetration at no additional cost to the Department.
581.04 Method of Measurement.
The Engineer will measure acceptably completed work for crack repair preparation by the foot along the exposed surface of cracks. The Engineer will measure acceptably completed work for crack repair inj ection by the gallons of epoxy used. Cracks that penetrate a concrete member at full depth, sealed on both sides of the member with injection/ inspection ports installed on both sides of the member verifying full penetration of epoxy adhesive, will be measured and paid for on both sides of the member. for Highway Construction Page 453 of 71 5 581.05 Basis of Payment . The Department will pay for accepted quantities at the contract unit price as follows: Pay Item Pay Unit Concrete Crack Repair Preparation ........................................................ FT Concrete Crack Epoxy Injection ............................................................. gal Coring injected areas to confirm full crack penetration and repairing the core locations is incidental . for Highway Construction Page 454 of 71 5 SECTION 582 – PATCH AND REPAIR OF CONCRETE
582.01 Description.
A.Concrete Surface. Repair and patch spalls, scaling, delaminations, honeycombing, and other deteriorated concrete on the surface of the girders, deck underside, pier caps, columns and abutments, including removal of debris from pier cap seats and abutment seats as specified and directed.
B.Concrete Deck . Repair spalls and delaminations in the bridge deck including determining the working areas by chain dragging or other approved method, preparing the concrete surface, repairing metal reinforcement , and applying the patching material.
582.02 Materials.
A.Preparation of Concrete Surfaces. Use material for patching and repairing the concre te surfac es that is cementitious, fast setting, non- sag, non- metallic repair mortar containing a corrosion inhibitor and meets the following requirements:
1.Compressive strength: 4,500 psi minimum at 28 days, in accordance with ASTM C109.
2.Bond strength: slant shear: 1,500 psi minimum at 28 days, in accordance with ASTM C882.
3.Drying shrinkage: less or equal to 0.10 percent, in accordance with ASTM C157 .
4.Permeability will be 2,000 coulombs or lower at 28 days, in accordance with ASTM C1202.
5.Freeze- thaw resistance will have a durability factor of 90 percent or higher after at least 300 cycles, in accordance with ASTM C666.
6.Coefficient of thermal expansion: between 5.3x 10- 6/°F and 6.4 x 10- 6/°F, in accordance with ASTM C5 31 (optional). Submit certified test results from an independent lab for products not on the QPL showing the proposed products meet the specifications. Obtain the Engineer’s approval before use.
B.Concrete Deck . Use material for patching and repairing the concrete surfaces that is cementitious, fast setting, non- sag, non- metallic repair mortar, and meets the requirements of ASTM C928, Type R3. Extend repair mortar as required using thoroughly washed and cleaned pea gravel. The Engineer will accept materials meeting the specified criteria with a manufacturer’s certification as specified in 106.04.
582.03 Construction Re quirements.
Meet the manufacturer’s written instructions for application of mortars. Removed materials are the Contractor’s property and must be properly disposed of.
Source: Idaho Standard Specifications for Highway Construction, 2023 Edition. Pages 486–489 of 768.