Air content of concrete is usually tested with a pressure meter.
Contractors are not always responsible for puddles on concrete balconies.
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The specifications for entrained-air content always include both minimum and maximum limits. I know that having too little entrained air reduces the concrete's resistance to freeze/thaw and deicer damage.
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What are "superflat" floors?
In Part 1 of our series on the importance of being able to read contract specifications, we look at reading blueprints.
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Is there a way to determine the compressive strength of concrete in-place, without removing samples for laboratory testing?
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Controlling moisture in concrete slabs can be tricky, but it's one of the most important factors a contractor needs to focus on.
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Home builders here in the Denver area recently have had a rash of scaling driveways. Literally hundreds of driveways constructed over the past two to four years are showing isolated to widespread scaling. Our firm and others have met with the builders to help determine the causes. We have conducted...
I am bidding on treating a concrete slab and one of the specified requirements is that there not be any birdbaths. The final surface will be flooded to see if this has been achieved. Do you have any suggestions?
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Although I've been lucky so far and have not had to deal with a failure of flooring materials applied over one of my slabs, it scares me to death thinking about it. What can I do to keep this problem from occurring?
Questions about field tests for SCC are answered.
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We are thinking about proposing the use of self-consolidating concrete on an upcoming project, but one challenge we face is coming up with acceptance criteria everybody feels comfortable with. What’s going on with the development of standardized tests for SCC?
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Do you have to be certified to calibrate equipment used for air pressure in 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 pres
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Does the water for concrete have to be completely void of salt (from seawater)? What happens if it is not?
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ACI 301-99, Section 1.6.7.3, regarding core test results, maintains that concrete represented by core tests is considered adequate when the average compressive strength of the cores is equal to at least 85% of the specified strength. I’m looking for any information that explains the basis for this...
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We are considering using self-consolidating concrete in bored cast-in-place piles up to 20-m deep. How can we check the level of compaction? Are there clear specifications for testing SCC and test specimens preparation? We cannot locate any ASTM or similar standards or material and workmanship...
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I seem to remember reading that testing for slump was very outdated and that there is really no difference between a 5-inch slump and 61/2-inch slump. Is this true?
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We recently placed a concrete floor with a laser screed. The floor had an FF requirement of 35 and an FL of 30.
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Our home is 2.5 years old, and the basement slab is constantly wet. Water is moving from the subgrade through the concrete. We did a pH test on the moisture, and it has a considerable acid content. The carpet, which was glued to the concrete, has come loose. What can we do about this problem?