Lightweight foam concrete containing expanded perlite and glass sand: Physico-mechanical, durability, and insulation properties

Foam concrete refers to a type of concrete with high porosity that can be produced with or without aggregate. Foam concrete has generally superior thermal insulation properties compared to conventional concrete. Despite its major thermal benefits, the high content of Portland cement, as well as its very high porosity, makes foam concrete prone to physico-durability concerns such as drying shrinkage by allowing the entrance of chemicals and free water to the concrete pores. To address this and reduce the pore network connectivity, in this study, expanded perlite and fine-sized waste glass sand were used as the main aggregates in concrete mixes. In that respect, 10 mixes of foam concrete were produced with two foam contents of 50 and 100 kg/m3, with a constant water-to-binder ratio (w/b) of 0.5. In each mix, the dominated expanded perlite aggregate was replaced by waste glass sand having a size of < 2.36 mm. Apparent porosity, water absorption, compressive and flexural strength, sorptivity, ultrasonic pulse velocity (UPV), drying shrinkage, freeze–thaw, alkali-silica reaction, thermal conductivity, and thermal resistance tests were performed to investigate the physico-mechanical, durability and insulation properties of the foam concrete. Based on the results, it is found that the addition of glass sand improves physico-mechanical and durability properties of foam concrete. The addition of expanded perlite increases the insulating properties of foam concrete, potentially due to the high porosity of expanded perlite compared to that of glass sand. The findings of this study point to the suitability of producing sustainable insulating foam concrete through the use of waste glass sand.