The Synergistic Utilization of Glass Aggregates and Glass Powder on the Thermal and Mechanical Properties of Concrete.

Abstract

Enhancing the utilization rate of waste glass in concrete is crucial for achieving solid waste reduction and low carbon emissions in the construction industry. This study employs the method of simultaneously replacing fine aggregate and cementitious materials in concrete with glass sand and glass powder to prepare composite waste glass concrete (CGC). The compressive strength, alkali-silicate expansion, and thermal properties of CGC were investigated experimentally. The experimental results show that the pozzolanic activity of fine glass powder in CGC can effectively mitigate the ASR reaction, enhance glass utilization, and allow the glass content to reach up to 17.79% of the total concrete mass. The thermal conductivity of the compounded waste glass concrete decreased linearly with increasing temperature, and the specific heat capacity showed three distinct peaks in the range of 180-800 °C, which were caused by chemical dehydration, quartz phase transition, and CaCO₃ decarbonization, respectively. Furthermore, to examine the impact of replacement mode on the high-temperature resistance of waste glass concrete, the residual strength, physical properties, and microstructure of the concrete were evaluated. It was found that the residual strength ratio of CGC (0.73) exhibited a distinct advantage at 600 °C. At this time, the melting effect of glass can reduce the pore size of concrete and transform large pores into capillary pores. However, as the temperature rises to 800 °C, the melting effect of glass no longer alleviates the high-temperature damage to concrete, and the degree of decomposition of hydration products determines the concrete strength.