Heat transfer and thermal shock of recycled glass concrete

Building Materials

In this paper, an experimental study is carried out to investigate the effect of thermal shock on the mechanical properties of recycled glass concrete exposed to temperatures between 150 °C to 600 °C due to rapid cooling regimes, namely, natural cooling, spraying water, using CO2 fire extinguishers, and immersion in water. The amount of waste glass replacement of fine aggregate resulting in optimal compressive strength is studied and then used in all specimens. The heat transfer in recycled glass concrete exposed to 600 °C for one hour using an electric furnace is studied, with the results validated via a finite element model. It is found that recycled glass can enhance the residual strength and reduce the severity of cracks in concrete subjected to thermal shock caused by rapid cooling from temperatures up to 600 °C to room temperature. Using recycled glass in concrete decreases temperature rise with time when exposed to elevated temperatures. The results obtained show that replacing 25 % of fine aggregate with recycled glass gives the maximum value of compressive strength. Compared with natural cooling, thermal shock generated by fast cooling regimes causes more severe damage to concrete, in terms of greater losses in compressive and tensile splitting strength and crack severity. Among the eight cooling regimes used in this study, natural cooling in air maintained a relatively higher value of residual compressive strength, while the highest reduction in strength was observed when using CO2 fire extinguishers. Tensile splitting strength shows the same trend.