Development of geopolymer-based lightweight high-strength concrete and properties at different temperatures

In the current study, a green and high-strength lightweight concrete is developed. Geopolymer-based lightweight concrete (G-LWC) is an innovative green building material that combines the advantages of geopolymers and lightweight concrete. Building upon existing research, to achieve low density, a lightweight aggregate, expanded glass powder (EGP), is used, resulting in the development of geopolymer-based lightweight high-strength concrete (G-LWHC) with a compressive strength exceeding 100 MPa. The influence of different EGP content and fiber admixtures on its density and mechanical properties is also studied, and its performance after exposure to high temperatures is analyzed from both micro and macro perspectives. The research results indicate that the incorporation of EGP significantly reduces the concrete density while also decreasing its compressive strength. G-LWHC exhibits significant temperature-induced ductility, with R_T,150^D increasing by 142.80% and 258.02% after exposure to 600 °C and 800 °C, respectively, compared to room temperature conditions. The addition of fibers has the most notable impact on improving the concrete's flexural strength. The developed G-LWHC exhibits characteristics of being lightweight, high-strength, and resistant to high temperatures, maintaining residual strength even after exposure to 800 °C.