Effects of cooling regimes on limestone rock and concrete with limestone aggregates at elevated temperatures

Abstract

In this study, the changes in the structure of limestone rock at 700 °C and different cooling regimes were investigated and C30 class concrete was produced with the aggregates obtained from the limestone. Concrete specimens were exposed to temperatures of 20, 200, 400, 550 and 700 °C for 3 h; cooled with air and water. Mass loss, ultrasonic pulse velocity and compressive strength tests were carried out on limestone and concrete specimens. In addition, limestone and concrete specimens at 20 and 700 °C were determined by polarizing optical microscopy and X ray diffraction. As a result, it was determined that the mass loss of the limestone and concretes increased as the temperature increased, and the ultrasonic pulse velocity and compressive strength decreased. The compressive strength of the limestone decreased by 45% with air cooling and 47% with water cooling at 700 °C; compressive strength of concrete decreased by 71% in air cooling and 61% in cooling by water at 700 °C.