Multiscale Design of Ecofriendly High-Performance Lightweight Two-Stage Concrete Composites Using Glass-Based Materials

Using lightweight glass-based materials from waste glass in concrete has economic and sustainable benefits in addressing the daily increase of waste glass. However, maximizing their use while fulfilling the mechanical and thermal requirements of structural concrete remains a challenge. This paper designed and developed a high-performance lightweight two-stage concrete composite (LTSCC), based on the concept of multiscale applications of various lightweight glass-based materials through a two-stage casting approach. A slurry infiltration setup was developed to ensure the uniform distribution of lightweight glass-based materials, where the foam glass coarse aggregates were preplaced in the mold and the lightweight high-strength slurries incorporating foam glass sands and hollow glass microspheres subsequently filled the voids under vacuum pressure and gravity. The results indicated that the LTSCC of designable densities and strength grades, including the high-strength grades, could be prepared with good microstructure homogeneity (without segregation or aggregate damage), low cement content (172.3 kg/m3), and high-foam glass content (up to 642.5 kg/m3). Furthermore, the LTSCC showed higher specific strength and cement efficiency than most lightweight concrete documented. The results of this study demonstrated a promising future for the application of the sustainable LTSCC with high content of waste glass-based materials in prefabrication, modular construction, and green building.