A Case Study of Concrete Incorporating High Volume Fly Ash and Bottom Ash for Sustainable Housing

Fly ash (FA) and Bottom Ash (BA) are commonly used to substitute cement and fine aggregate in concrete production. This study was performed to evaluate the use of high-volume fly ash and bottom ash on a sustainable housing project. High-volume fly ash (HVFA) is used as supplementary cementitious materials, while high-volume bottom ash (HVBA) is used to partially replace the fine aggregate. The FA used in this research was 40% and 50%, and the BA used in this research was 50% and 75%. The fresh and hardened quality of concrete incorporating HVFA and HVBA was evaluated using slump, compressive, flexure, and tensile test. The fresh properties show that adding FA to the concrete mixture can increase the slump value. However, the BA tends to reduce the slump value in concrete due to its particle characteristics. Furthermore, it was found that concrete incorporating HVFA and HVBA has lower compressive, flexure, and tensile strength, especially at an early age. As the curing age of concrete increases, the differences between concrete incorporating HVFA and HVBA with concrete mixture decrease. In this research, the concrete incorporating 40% FA and 50% BA has the optimum quality. Furthermore, the mixture is later used in the field application as structural elements for the village-owned Enterprise building built in the Sumberejo Village East Java Indonesia. The use of HVFA and HVBA in this pilot project is expected to minimize the cost and experimental problems due to the coal ash waste.