Foundation, Concrete and Earthquake Engineering

Workability Requirement for No Fines Concrete

Dear reader we were discussing about no fines concrete throughout last two posts and including this post, several posts will be published very soon. Workability of concrete is very important property that defines ease of work with concrete. We know different tests are conducted to examine workability of normal concrete.

But these have no workability test for such concrete; we know no fines concrete is special type of concrete where fine aggregate is eliminated; therefore workability requirement is also changed. Here only visual inspection of concrete is enough where we will examine whether or not coarse particles is coated with cement paste sufficiently.
We know a thin cement layer is expected over coarse aggregate, therefore no-fines concrete should be placed (conveyed and compacted) very rapidly to avoid drying out of thin cement paste coating. An improperly placed (here delayed) concrete will obviously produce weak concrete (low strength).

So, though simple test is enough to check workability but great care in placement is important to produce desired strength of such concrete. Dear reader in our next post we will learn about compaction of no fine concrete. Till then good bye.

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