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We are bidding a concrete project on which slump doesn't seem to be specified. In the specifications there is reference to ACI 301, "Specifications for Structural Concrete for Buildings," and to ASTM C 143, Standard Test Method for Slump of Hydraulic Ceme
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Where can we get a deeply colored paint for concrete, one that is highly saturated with primary color? We need it for a multiuse building 600 feet tall. The owner wants several bright colors, not the stains, pastels, and earth tones commonly used on concr
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We re replacing concrete floors, pads, and pedestals damaged by hydrofluoric acid spills in an oil fuel processing plant. The acid is at ambient temperature and concentration varies from 10% to 60%. How do we protect the new concrete so it doesn't deterio
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We placed the concrete for post-tensioned decks for a three-story health club.
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We need more information about the "grass plus concrete" load-bearing lawn, described in your September 1988 issue (page 863). Who is familiar with the system in Quebec? Who is the maker of the reusable plastic form unit?
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I've recently been awarded a contract to whitetop an existing asphalt parking lot in Pennsylvania. One section of the lot is 80x200 feet. Should there be an expansion joint in a section of lot this large?
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We're applying a two-component polyurethane coating to the walls and floor of a new concrete reservoir. It's a high-build, 100% solids coating sprayed 125 to 140 mils thick in one pass. We first sandblast the concrete surface and repair any bugholes with
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We put in the foundation and floor slab for a house about 3 years ago. The floor slab performed fine for 2 years but then started heaving and cracking. Some of the cracks are up to 1/8 inch wide. Could water pressure have caused the heaving and cracking?
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Is it better to use air-dried or kiln-dried wood for formwork?
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What's the significance of percent solids in liquid membrane curing compounds? The cure-and-seal products seem to have a higher solids content. If two products meet the ASTM requirements for curing compounds, is the one with a higher percent solids more d
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Where can we buy graphite form ties?
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Is it acceptable to batch concrete with aggregates below the saturated surface-dry moisture state? If not, what standard prohibits it?
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We're going to be placing a 6-inch-thick concrete slab in a cold storage warehouse. The concrete has to be placed over 12 inches of expanded polystyrene insulation board. The insulation comes in 4x8 foot sheets that are 6 inches thick, so there will be tw
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We frequently are asked to strip slab formwork based on compressive strength, as determined by test cylinders, reaching 80% to 85 % of the 28-day specified compressive strength. Often we get this strength 3 days after placing the concrete. However, we not
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We placed a concrete floor in an unheated 300,000-square-foot warehouse. Control joints were sawed on 20-foot centers each way. We filled the joints with epoxy but there has been quite a bit of joint movement and now the joint filler is pulling away from
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What causes delayed setting of superplasticized concrete? We placed a 2-foot-thick slab on grade for a water treatment plant. Maximum air temperature during the pour was 65 degrees F. We placed the concrete directly onto a polyethylene vapor barrier. At m
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We're saw cutting a road that consists of 6 inches of concrete overlaid with 1 inch of asphaltic concrete. In most places there's only 1/2 inch of asphalt left. The cut is 3 inches deep and our saw blades are lasting for only 500 lineal feet of cutting. I
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We heard that epoxy-coated welded wire fabric is being used. Is there a standard specification for the material?
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Specifications for a concrete deck for a swimming pool call for a keystone finish. What is it?
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We've got problems with bugholes in an 8-inch-thick architectural concrete wall that we're building. It's 4 to 6 feet high and the surface looks fine, except in the top 1 foot where lots of bugholes have formed. The air-entrained concrete is colored with