Concrete producers, who long have used some computer programs in their back office and batching areas, are seeing the benefits of adding new programs and integrating their systems. Computer companies, meanwhile, are taking advantage of high-efficiency chips, larger memory capabilities, and wireless...
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Q: We plan to bid on some state bridge deck work planned in our area. Our district engineer is open to allowing a high-performance mix that will help mitigate the possibility of undue cracking. Our lab is analyzing several mixes with standard features such as strength, set time, and chloride...
The 52-story Wachovia Corporate Center is the focal point of the new mixed-use Wachovia Cultural Campus, which will include a 42-story condominium tower, art museums, and 1200-seat performing arts theater. The two towers, along with a nine-story building annex, sit atop an eight-story parking...
We are involved in a dispute on the quality of a decorative slab for which we supplied concrete last fall. The project appears to be fine, but one set of test cylinders failed to meet compressive strength requirements.
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We recently supplied several split-face blocks for a large commercial project. The work continued for several months, and with about two weeks left, we started receiving complaints about the quality of the units from the mason contractor.
Modern technology and automation have finally entered the concrete testing laboratory. Several technical committees have updated traditional standards to accommodate this new technology.
Concrete strength testing is a much larger problem for ready-mix producers than many in the industry realize.
QC managers say testing labs often fail to follow correct procedures. The burden of proof of good performance falls to the producer.
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ASTM C-1644-06 provides guidance on connectors between concrete wastewater tanks and pipes.
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Compressive strength is one of the most important measurements in manufacturing concrete. As a producer, I need to know whether this measurement is accurate. How can I be sure my concrete compressive strength results are correct?
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More of our customers are starting to ask us about the possibility of using self-consolidating concrete. What’s going on with the development of standardized tests for SCC?
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How thick should concrete be to withstand four hours of temperatures of 2000 degree F without degrading or failing? The concrete barrier likely will be exposed to more than 2000 degrees F. The barrier would be more than 30 feet tall and more than 30 feet long. It will be outdoors and subject to...
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Is there a quick test to detect the presence of iron sulfide in aggregates? The aggregate I am considering will be used in an exposed decorative application, so repeated wetting and drying of the aggregate will occur at the surface. I also am concerned it may cause staining.
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Is there a good way to correlate core compressive strength and flexural strength? I have a job in which there was only one beam broken, at 28 days, and there are not enough sets to perform any statistical analysis. We are planning to core the pavement and are looking for a comparison between the...
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Editor's note: Two readers responded to recent articles on self-consolidating concrete (SCC).
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Editor's note: Two readers responded to recent articles on self-consolidating concrete
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Is it common to get different air readings when using a pressure meter and a roll-a-meter or volumetric meter? I continually get a difference of about 0.8% to 1%, but I feel very sure my meters are calibrated correctly. The higher reading is from the pressure meter.
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A flooring contractor has experienced problems on four occasions over the years with his two-part polyurethane floor covering not bonding to our concrete slab-on-grade. He has said that the acid-etch process prior to installing the covering did not react very well with our slab surface, based on...
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I have a further question regarding the rounding of compressive strength results (ôHow Precisely Should Labs Round off Compressive Strength Results?ö April, page 26).At our lab, we test 4x8-inch and 6x8-inch concrete cylinders for compressive strength, and we round to the nearest 10 psi according...