Pre- and post-fire behaviour of glass concrete from wet packing density perspective

Abstract

Recycled glass can be ground into different particle sizes to partially replace cement or aggregates, which is important for developing sustainable concrete production. In this study, a total of 16 concrete mixes containing glass powder (GP), silica fume (SF) and glass sand (GS) were designed to investigate the fresh and harden material properties at ambient temperature, heat transfer mechanism and temperature development, mass loss, apparent change of surface texture as well as residual compressive strength and elastic modulus after exposure to elevated temperatures (400–1000 °C). Results show that glass concrete possesses larger slump flow and suffers less mass loss which are believed to be caused by the improved wet packing density (WPD) and the existence of more abundant excess water. Besides, replacing cement partially with GP up to 15% and/or SF up to 10% would enhance the compressive strength by 11.6% and 4.7% respectively and elastic modulus by 4.5% and 5.3% of concrete. At elevated temperatures, the core temperature of concrete containing GP was lower, indicating that GP could provide an effective solution in improving the concrete's heat-insulation capacity due to the enhanced WPD. After exposure to 400, 600, 800 and 1000 °C, the incorporation of glass in concrete was effective in enhancing the residual compressive strength by maximum 15.2%, 38.3%, 9.1% and 37.5% and elastic modulus by maximum 7.5%, 17.3%, 19.4% and 19.5%, respectively due to the enhanced WPD and re-solidification of GP/GS in its molten state that strengthened the interface transition zone.