520.04 Structural Concrete Repair By Sealing and Injection
516 SECTION 520
520.01 Description
This work consists of restoring the structural integrity of portland cement concrete (PCC) structures by injecting and sealing cracks, delaminations, and hollow planes with an epoxy resin system.
520.02 Materials
A.Injection Ports Provide injection ports such as tubes, fittings, or pressure plates for the epoxy resin system under injection pressures of 60 psi [0.4 MPa]. Provide a seal for each injection port.
B.Crack Sealer Provide a sealing compound specified by th e epoxy resin manufacturer to seal cracks in concrete and to anchor the injection ports.
C.Pressure Plates The Department will allow the use of pressure plates instead of sealing compound, as approved by the Engineer. Provide clear plastic pressure plate s that cover the entire crack.
D.Epoxy Resin System Provide an epoxy resin system in accordance with Subsection 701.13.A, “General” Type D.
520.03 Equipment
Provide a pressure pot, hand pump, caulking device, injection machine, or other device to inject the epoxy resin. Provide a special pressure fitting on the injector to prevent leaks when injecting the epoxy resin through the ¼ in [6 mm] holes in the pressure plates. Drill the injection ports using equipment with a vacuum system to prevent dust from compacting into the cracks and laminations.
520.04 Construction Methods
A.Preparation Clean the surfaces adjacent to cracks of efflorescence, deteriorated concrete, and other surface debris detrimental to the adh esion of the surface sealing epoxy compound. Clean the interior surfaces of the cracks with air under sufficient pressure to remove loose materials entrapped within the crack including efflorescence. When sealing cracks underwater, use appropriate cleani ng methods as approved by the Engineer. After cleaning, drill injection port holes using a swivel drill chuck and hollow drill bits including a vacuum attachment which will remove dust and debris generated during drilling. STRUCTURAL CONCRETE REPAIR BY SEALING AND INJECTION 520.06 517 Determine the spacing of the in jection ports holes by the size of the crack and the depth of the crack in the concrete substrate. Generally, space the injection ports from 4 in to 8 in [100 mm to 200 mm] apart. Space the entry ports so material can travel between them. Drill the hole s to a minimum depth of ⅝ in [16 mm]. Insert the injection ports in the drilled holes approximately ½ in [13 mm], allowing for a small reservoir below the injection port. Apply a quick -setting seal around the injection ports to prevent resin loss. The Engineer may approve sealing with a clear plastic plate. Prevent defacement of the concrete surface.
B.Epoxy Resin Injection Inject the epoxy in accordance with the epoxy manufacturer's instructions. Determine the actual injection procedures and pressur es in field trials, based on crack widths and depth into the substrate and sufficiency of the results. Start at the lower port. Continue pumping until sighting the resin at the port directly above or adjacent to the injection port. If material is sighte d at an adjacent port, move the nozzle to the port showing resin, and seal the previous injection port. Continue this procedure to completely fill the crack. On wide cracks, the Department will allow simultaneous pumping of two or more ports.
C.Clean Up Clean concrete surface areas of excess epoxy materials and injection ports after completing the epoxy injection work. Clean in a manner which will not damage the concrete by scraping, light sand blasting, grinding, use of solvents, or any other appropria te method approved by the Engineer. Clean excess materials so that no epoxy material or injection ports extend beyond the plane surface of the concrete.
520.05 Method of Measuremen T — Vacant
520.06 Basis of Payment
The Department will pay for each pay item at the contract unit price per the specified pay unit as follows: Pay Item: Pay Unit:
A.PREPARATION OF CRACKS, ABOVE WATER Linear Foot [Meter]
B.PREPARATION OF CRACKS, BELOW WATER Linear Foot [Meter]
C.EPOXY RESIN, ABOVE WATER Gallon [Liter]
D.EPOXY RESIN, BELOW WATER Gallon [Liter]
521.02 Pneumatically Applied Mortar
518 SECTION 521 PNEUMATICALLY APPLIED MORTAR
521.01 Description
This work consists of providing and placing pneumatically applied mortar to: Construct portions of structures, Repair concrete structures, Texture concrete surfaces, Encase structural steel members, Line ditches and channels, and Pave slopes. This work includes preparing surfaces to receive mortar, and providing and placing reinforcing steel and anchors for reinforcement.
521.02 Materials
A.General Provide pneumatically applied mortar with a minimum of compression strength of 4,000 psi [27.6 MPa]. Provide materials in accordance with the following subsections: Material: Subsection: Fine Aggregate 701.05 Coarse Aggregate 701.06 Water 701.04 Portland Cement 701.02 Bar Steel Reinforcement – Billet Steel 723.01 Welded Steel Wire Fabric 723.02 Use no more than 30 percent coarse aggregate in combinations of fine and coarse aggregates. Provide coarse aggregate in accordance with Subsection 701.06, “Coarse Aggregate,” with gradation in accordance with AASHTO M 43, No. 8 or No. 89. The Department will allow the reuse of clean cement - covered fine aggregate (recovered rebound). Limit the use to no mo re than 20 percent of the total fine aggregate.
B.Anchor Studs If placing mortar against existing concrete or rock, provide anchor studs with at least ¼ in [6 mm] diameter expansion hook bolts placed in drilled holes to support reinforcing wire fabric or bars. Ensure individual bolts can resist a pullout force of 150 lbf [670 N]. Obtain the Engineer’s approval before using driven steel studs. Use driven steel studs with a diameter of at least ⅛ in [3 mm] and a length of at least 2 in [50 mm].
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Source: Oklahoma Standard Specifications for Highway Construction, 2019 Edition. Pages 530–531 of 935. View official source ↗