Experimental Study on Lightweight Concrete through Partial Replacement of Cement with Fly Ash and Fine Aggregate with Thermocol

Abstract: Lightweight concrete provides a sustainable way to decrease the weight of structures, improve heat insulation, reduce environmental impact and make buildings more resistant to earthquakes. This research looks at creating lightweight concrete using fly ash (30%, 40%, 50%, and 60%) instead of some cement and thermocol (0.2%, 0.4%, and 0.6%) instead of some fine aggregates. We made 78 cube samples (each 150 mm × 150 mm × 150 mm) and 26 cylindrical samples (150 mm in diameter and 300 mm in height). These samples were made and then kept for different periods before testing. The samples are classified into two groups: one was left for 7 days of curing and the other for 28 days. Each group has three cubes to study how much pressure they could handle and for the cylindrical samples, we tested one from each group to see how much force they could resist. The aim is to make the concrete lighter while maintaining the required strength. Fly ash, which comes from burning coal, makes the concrete easier to work with and more environmentally friendly. Thermocol makes the concrete much lighter and better at insulating heat. The concrete samples were tested for their compressive and tensile strength during testing. The results showed that the concrete became much lighter maintaining the required strength, making it compatible for the desired purpose. By including waste materials such as fly ash and thermocol, this method provides a more environmentally friendly and cheaper alternative to regular cement concrete mixture. The results show that it can cut material costs, reduce CO₂ emissions, and encourage sustainable building practices. This approach of using lightweight concrete significantly contributes to the development of sustainable infrastructure while addressing the growing demand for less environmentally conscious construction practices.