Sustainable structural lightweight concrete containing foam glass aggregates

Recently, various types of lightweight concrete have been developed through the combination of different lightweight aggregates and cementitious matrices. This study investigates the replacement of natural coarse aggregates with foam glass to produce lightweight structural concrete, aiming to reduce the environmental footprint of traditional concrete materials. Foam glass aggregates, synthesized from both virgin and recycled glass using an innovative laboratory-scale method, were evaluated as substitutes at replacement levels of 20%, 40%, and 60% by volume. The aggregates were used in granulated and crushed forms to assess their performance compared to conventional natural aggregates. Key findings demonstrate that concrete with 20% foam glass replacement achieves a bulk density below 2000 kg/m 3 and compressive strength exceeding 17 MPa, meeting the criteria for structural lightweight concrete. Durability tests, including alkali-silica reactivity (ASR) and thermogravimetric analysis (TGA), confirmed the non-reactive behavior of foam glass aggregates, ensuring long-term performance. This research establishes foam glass as a viable alternative to natural aggregates, contributing to sustainable construction practices while maintaining structural integrity and reducing material weight. • An innovative two-stage sintering method was developed to synthesize foam glass aggregates with intact outer shells from virgin and waste glass. • Foam glass aggregates were tested in granulated and crushed forms, with granulated aggregates demonstrating superior performance. • Replacing 20% of natural coarse aggregates with granulated foam glass produced lightweight concrete with a density below 2000 kg/m 3 and compressive strength above 17 MPa. • A novel thermogravimetric analysis (TGA) method confirmed the non-reactive nature and durability of foam glass aggregates while highlighting their pozzolanic activity. • This research advances sustainable construction practices by demonstrating the viability of foam glass as an eco-friendly alternative to natural aggregates in structural concrete.