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Q & A: weighing concrete

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Most recent answer: 10/22/2007
Q:
Myself and a couple of other old farts been contemplating this for a few days and we canít reach a consensus.

Assume you have; 4 pounds of aggregate, 4 pounds of concrete, and 2 pounds of water to mix with the concrete and aggregate. After the mixing is completed and the compound is laid and cured... does the resultant block weigh 8 pounds, 10 pounds, or something in between?

I think the result would be something just over 8 pounds because it is unlikely that ALL of the water molecules would be released as catalyst energy.

Secondarily, could you use a scale to measure the rate of cure?
- Lee Wonnacott (age 56)
Kannapolis, North Carolina
A:
As one old fart to another, none of us are as good as nature itself in answering something like this. Why not just do the experiment? Concrete is cheap. But meanwhile hereís my guess.

I bet youíll end up with almost 10 lbs. The water gets taken up in the chemical structure of the concrete. You could even end up slightly gaining water, depending on the humidity of the atmosphere.

Mike W.

(published on 10/22/2007)

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