Enhancing the sustainable production of Foamed Concrete by using different waste materials as a full sand replacement

Industrial activities generate substantial waste, much of which is disposed of in landfills rather than being recycled. The aim of this study is to investigate the potential of incorporating waste materials as substitutes for sand in foamed concrete (FC), with the goal of enhancing its physical and mechanical properties while promoting environmental sustainability. Stable foam was first produced using foaming agents, Sodium Lauryl Ether Sulfate (SLES) and Sodium Dodecylbenzene Sulfonate (SDBS), through mechanical stirring and a custom-made foam generator. Foam stability tests and Fourier Transform Infrared Spectroscopy (FTIR) were conducted to assess the foam performance. Following this, FC specimens were prepared by fully replacing sand with different waste materials, such as clay brick, granite, basalt, and shredded rubber. The mixes were designed to maintain uniform fine particle distribution, achieving dry densities of 1650 kg/m${}^3$ and 1250 kg/m${}^3$. The specimens were then evaluated for compressive strength, water absorption, and thermophysical properties. Additional analysis was conducted using mercury intrusion porosimetry (MIP) and Scanning electron microscope (SEM). Results highlighted the significant influence of foam generation methods and surfactant choice on foam performance. All waste-incorporated FC mixes demonstrated superior performance compared to conventional sand-based mixes by achieving a combination of enhanced mechanical and thermal properties. Notably, granite and clay brick waste enhanced both mechanical strength and pore structure, making these mixes particularly suitable for structural applications. The findings demonstrate that integrating waste materials into FC not only supports sustainable construction practices but also improves its overall performance.