Fresh concrete exposed to short term high heat ~ 600 deg C

by Mark
(Australia)

Q. This is an industrial question really...I have a steel lined sump which is leaking. The sump manages strong caustic solution. Over time the undetected leak has reacted with the concrete encasing the sump and caused heave, which has pushed the sump base up. To repair, the sump base will be cut away and concrete repairs effected. I expect the repairs will be approx 1.2-1.5 metres in diameter and maybe 75-100mm thick. So far so good. A new steel floor is then to fully welded and then will be stress relieve. This process evenly heats the steel over a few hours to 600 deg C, held at that temp. for an hour and then allowed to cool slowly. I am concerned that exposing 1-2 day old concrete or other product to this temp. will be detrimental to the entire repair. Do you have any comments or suggestions, or recommend a particular product that may be of some help? Thanks for reading.

A. There is a heat resistant concrete repair product called 5-STAR STRUCTURAL CONCRETE HTR. It is a fast setting concrete repair material that can be used as structural concrete or just as a repair material.

HTR can be exposed to temperatures as high as 1800ºF, depending on application and placement conditions, within 24 to 72 hours.