Evalution of concretes with standard and recycled raw materials for high temperature application

Abstract

Concrete undergoing thermal treatment before and during life-service can be applied as building material for thermal insulation in high-temperature plants. When such concretes are designed with secondary raw materials they show satisfying performances. Sintering and microstructural changes occur within concrete with increasing temperature. Change progression can be monitored by measuring compressive strength and porosity with destructive and non-destructive tests (ultrasonic pulse velocity technique, image analysis). Experiment has been performed on standard, corundum concrete and recycled, bauxite concrete. Samples were thermally treated from 110 to 1500 degrees C. Destructive tests were used in compressive strength and porosity investigation. Non-destructive tests were performed in order to compare results. Creep testing was conducted to prove sintering process. Results showed that recycled concrete has equal properties as standard concrete.