Effects of High Temperature on High-Performance Fine-Grained Concrete Properties

Abstract

The dense development of high-rise construction in urban areas in Vietnam requires the creation of new concretes with essential properties for fire safety solutions and for high temperature. In this study, the effects of high temperature on high performance fine-grained concrete properties were investigated. Concrete samples were exposed to high temperatures at 300 °C at 4, 5, and 6 h, then cooled to ambient temperature before tests. Two mixtures of Normal Fine-grained Concrete (NFC) and High-Performance Fine-grained Concrete (HPFC) containing 10% silica fume (SF) and 50% bottom ash (BA) were designed in accordance with an absolute volume method. Mass loss, residual compressive strength, and X-ray analysis were performed to investigate the effect of high temperature at different times on the performance of NFC and HPFC. The results of this study showed that the compressive strength of HPFC mixture containing SF and BA obtained is significantly greater than that of the NFC at 300 °C for different curing ages. This can be explained by enhanced reactivity of SiO2 amorphous in the SF and BA contents in HPFC, which binds more calcium hydroxide at higher temperatures, a percentage of calcium silicate hydrates increases, and the presence of Tobermorite and Xonotlite secondary particles are confirmed through XRD analysis.