Cyclic Heating and Cooling Effects on Concrete Durability

Abstract

The main objective of this investigation was to determine effects of cyclic heating on the strength of portland cement concrete subjected to high temperature, and to compare the effects of cyclic heating on concrete contaminated with hydraulic fluid and jet fuel with non-contaminated concrete. Five different concrete mixtures were investigated. Twenty one prisms and twenty-one cylinders were made from each mixture and were tested for compressive strength, flexural strength, pulse velocity and dry unit weight. Within each group, three specimens were tested after each of the following heating/cooling cycles: 0, 15, 30, 60, 120, 240, and 400. Each cycle consisted of 60 minutes at 400 degrees F followed by 30 minutes at room temperature. After every 15 heating/cooling cycles, the contaminated specimens were soaked in jet fuel or hydraulic fluid for overnight before the next heating/cooling cycles. Test results indicate that jet fuel contamination is more detrimental than hydraulic fluid contamination. Compressive strength, flexural strength, and pulse velocity are adversely affected by the cyclic heating.