fire damaged slab rebuild

[ragedriven]

whats a good scope for re-testing? the insurance company wants to keep the slab, the initial testing company said no way. We are the 2nd opinion.

An industrial sized warehouse burned, the slab on grade quality is in question. In general it can remove the water content, cause surface spall, it can release concrete/aggregate bonds, ect.

The initial testing scope involved many swiss hammer and 6 cores (limited on purpose). The spec required is 3k, 2/6 cores passed, 4/6 cores failed (40-50%). Test engineer said destroy the slab, but would permit delineating failing sections if economical.

looked through these...
thread590-75263
thread590-108730
thread590-176975

i wouldn't trust a swiss hammer as far as i could throw it, maybe as a measure of uniformity, but not for actual compression correlations. what insitu testing should i perform in addition to the destructive coring/breaking?

windsor probe? more swiss? break off? ultra sonic?

 

[conceng]

I would start with a chain drag to check for delaminations. I would also consider sending a good core or two to a petrographer to see how deep the fire damage goes.

The compressive strength results will only give you the strength of the weakest layer. If the top surface got too hot, the durability could be significantly compromised regardless of the core results.

Insurance companies are kinda funny to work with. What about the maintenance nightmare created by all the new cracks. I figure if the fire got hot enough to alter the strength, it likely got hot enough to cause some new cracking.

Gregory A. Johnson, P.E.

http://www.midwesttestinglabs.com