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What's the nominal weight of standard concrete?
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Why does it seem that moisture-related flooring problems are more common today than in the past?
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Concrete finishes are sometimes described by means of the letter F followed by a number. When are the various finishes called for and how are they produced?
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Please tell me how to correctly prepare and apply a concrete topping. We recently placed a slab, and then topped it with a mixture of 1 part cement and 3 parts sand. The slab was given a broom finish before the topping was applied. We did not use a bonding agent between the slab and the topping...
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What is the R-value of a typical 8-inch-thick, cast-in-place, residential basement wall?
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What are the differences between prestressed, pretensioned and post-tensioned concrete?
What is sweating slab syndrome and how can it be prevented?
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We're designing a retaining wall that consists of precast concrete units stacked on each other. What's the coefficient of friction for concrete on concrete? The manufacturer of the units says it's 0.75, but that sounds high to me.
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I have a residential-concrete specification that calls for a 1:2:4 concrete mix. What does that mean?
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I attended a seminar at which a speaker said that concrete doesn't expand. I told him I've always read that concrete expands when the temperature rises or when the moisture content increases. The speaker held his ground, however, and said that concrete doesn't expand. Is my literature outdated?
We recently were called to apply an epoxy surface to a newly constructed 6-inch-thick warehouse slab with a tight 12x12-foot sawcut control joint pattern. Can you explain what may have caused these random cracks to develop?
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In the article on sealing joints of tilt-up panels (April 1974, page 171) the word "laitance" is used. This word has frequently appeared in our concrete specifications over the years but we have never been able to find it in our dictionary. What is a good definition?
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Are joints in concrete meant to accommodate expansion or contraction? Someone told me that what I've always called expansion joints I should now call contraction joints. Does this mean that concrete doesn't expand? What are these joints actually supposed to do?
We're soon starting a job that calls for structural lightweight concrete. How does this material differ from normal weight concrete and what should we be prepared for in working with it?
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At what temperature does concrete cure best?
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We frequently hear about the ACI Building Code and ACI specifications for concrete for buildings. Are these the same thing? Do they automatically apply to any building we might want to build?
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We're designing the concrete floor for an auto dealership's service department.
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Our placing crew splattered concrete on an aluminum storm door when we were placing a patio.
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What is meant by the common term 'cold joint?"
We were placing a large concrete patio that was to have an exposed-aggregate finish. After placing and bullfloating the slab, we spread a layer of decorative aggregate across the surface, pressed it down so it was completely embedded in the concrete, then hand-floated the entire surface, slightly...