The effect of inadequate compaction on compressive strength of concrete exposed to elevated temperature

Abstract

One of the important factors affecting the quality of concrete is the placement of fresh concrete inside the formwork. Inadequate compaction is a common problem in concrete technology. In this study, the effect of inadequate compaction on compressive strength and ultrasonic pulse velocity of concrete exposed to elevated temperature is examined. For this purpose, various compaction rates were applied during the casting stage of concrete in order to simulate various levels of inadequate compaction. Four different water-cement ratios (0.50, 0.40, 0.38, and 0.35) were selected. All concrete specimens were exposed to 450 or 900° C for one hour. The Taguchi approach was used to reduce the number of samples. The results were evaluated by the Analysis of Variance (ANOVA) method. Test results showed that inadequate compaction played a significant role, more than curing time, in the compressive strength after high temperature exposure.