Any experience with excessive retardation of concrete?
Any experience with excessive retardation of concrete?
(OP)
I am trying to help a client who has had a problem with excessive retardation of concrete in drilled shafts (piles).
When tested by sonic logging at 7 days some of the concrete had low UPV. When retested at 14 days UPV had increased by 50 percent. The mix was self-consolidating (9 inch slump) with double the recommended dose of Master Builders Pozzolith 300R. I am looking for any conference papers or journal articles describing similar experiences. Can anyone point me in the right direction?
When tested by sonic logging at 7 days some of the concrete had low UPV. When retested at 14 days UPV had increased by 50 percent. The mix was self-consolidating (9 inch slump) with double the recommended dose of Master Builders Pozzolith 300R. I am looking for any conference papers or journal articles describing similar experiences. Can anyone point me in the right direction?





RE: Any experience with excessive retardation of concrete?
RE: Any experience with excessive retardation of concrete?
RE: Any experience with excessive retardation of concrete?
I'm not sure, but the following site may have information that is useful to your purpose:
www.ndt.net/article/v05n02/castro/castro.htm
The material and lack of fineness can have a big impact on the retardation. Doubling the recommended dose would likely have an even bigger impact (ie., greater than 2X, because there is less cement to hydrate). I assume that you've already checked with Masterbuilders regarding their product. They should have tekkies that have a really good handle on their product as well as info on using it in greater quantities.
Only other case I've heard of regarding severe retardation was a railroad tanker car that was transporting cement powder that had previously been used for transporting sugar. I guess that sugar really messes with the gel!
RE: Any experience with excessive retardation of concrete?
RE: Any experience with excessive retardation of concrete?
Thank you.
RE: Any experience with excessive retardation of concrete?
Thanks
Thuy Ai Nguyen
Senior Analytical Chemist
Essroc Cement