Influence of particle size of glass aggregates on the high temperature properties of dry-mix concrete blocks

The high temperature properties of glass aggregates (i.e. thermal conductivity and melting temperature) play important roles on the performance of the glass concrete. It has been known that when glass aggregates are incorporated in concrete and the concrete is subjected to elevated temperatures, the melted glass surface could act as a binding material to mitigate the high temperature damages in the interfacial transition zone (ITZ) between the cement paste and the glass aggregates. In this study, the influence of the particle size of the glass aggregates on the properties of dry-mix glass concrete blocks after exposure to elevated temperatures of up to 800 °C was investigated. In order to avoid the influence of the pozzolanic reaction of the glass, glass particles of <0.3 mm were not used in this study. It was observed that the smaller the glass particle size was, the better was the improvement of the high temperature performance. This was due to the larger surface area as revealed by X-ray µCT observations. Similarly, SEM-BSE images indicated that after exposure to 800 °C more crystal-like patterns were detected on the surface of glass aggregates in the blocks made with smaller glass aggregates, which indicated that more melted glass surfaces could contribute as binding materials to provide higher residual strength after cooling.