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We recently supplied controlled low-strength material (CLSM) for backfill. Specifications called for a maximum 28-day compressive strength of 200 psi to allow excavation by backhoe at a later date. We designed for a strength between 50 and 150 psi, but cylinder breaks indicated compressive...
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After one of our customer-contractors poured an integrally colored patio at a new residential home, the homeowner had the carpenters add a railing to the adjacent redwood deck. Afterward, wood debris covered a portion of the patio. During the final walk-through at loan closing, the homeowner...
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During the heavy floods we experienced this past spring, our concrete sand was contaminated with lignite. We don't have enough room to build another sand stockpile, and I want to avoid hauling it back to the quarry and paying rehandling costs. Is there any way I can use the contaminated sand but...
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What are the new North American Industrial Classification System (NAICS) codes for aggregates and concrete construction businesses?
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What is hot cement? When does it occur? Does it affect our concrete?
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Our floating pumps occasionally suck up trash and vegetation from the lake's bottom. How can we protect our water flowmeter from the debris that gets through pump's strainer?
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When pricing concrete, our salespeople have a problem with projects for which there are conflicting specification requirements. Some engineers and architects in our area specify both compressive strength and maximum water-cement ratio, but the water-cement ratios are ridiculously low for the...
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We manufacture concrete pavers and are experiencing a severe efflorescence problem. Can we reduce efflorescence by using admixtures such as plasticizers or pozzolans? Or should we use silicone-type water repellents or film-forming sealers on the finished product?
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The county engineer suggested we revise the drainage around our plant to separate our storm water from our process water. Why would I want to do this, and how would this affect my storm water permit?
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Recently the plant's baghouse has not been effective in evacuating the dust at the pickup points. It doesn't seem as if there is enough air movement through our shaker-style unit. What should we do?
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We have just begun production on a precast bridge deck that calls for production of thousands of match cast deck segments sized approximately 3.5x7x2 meters. Our operation uses the freshly cast segment as a forming unit. We plan to accelerate the cure for the first two hours of the 12-hour curing...
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We get a lot of popouts in exposed concrete. The expansive materials are shale particles found in the sand. Even though the shale particles may be no larger than 1/8-inch in diameter, a conical fracture shape makes the popouts more noticeable. Can this problem be avoided?
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As we were about to start production of the prestressed members for a new job, an engineer from the testing lab inspected the steel strand. He rejected it because it was too rusty. Is there a way to determine whether rusting will have a harmful effect on strand performance?
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