| This
presentation will cover a great many topics that affect the shrinkage,
cracking and curling of concrete. Typical concrete shrinks about 0.06%. In
this presentation the emphasis for the concrete mix design will be on
reducing the shrinkage to 0.04%, 0.02% or even 0.00% by the use of the proper
coarse aggregate size & quantity and by the use of shrinkage reducing
& shrinkage compensating admixtures. We will cover how to write a spec to
achieve these low shrinkage percentages. We will also look at what happens after the concrete is placed, ncluding the use of an evaporation retarder, proper curing, joint layout, sawcutting, etc. There are many tests that are typically run on the concrete at the jobsite and in the weeks following, but none of them tell us right there at the job site in real time if concrete is likely to shrink, crack and curl. We will cover the one job site test method that will provide that critical information immediately. |