Flagcrete: Fly Ash and Fine Powder Glass as a Sustainable Aggregate and Binding Agent in Concrete Hollow Blocks (CHB)

Environmental issues such as waste management have existed for many years, where humans continue to explore waste reduction methods for sustainability. This study aims to discover a way to reuse consumer glass waste and fly ash, wastes from coal power plants, by testing its effectiveness as an alternative aggregate and binding agent for the production of hollow blocks. Hollow blocks were made from concrete mixture composed of cement, aggregates, and water. The mixture was put in a hollow block machine, where it was molded and compressed into a hollow block. It was then cured for 7 days. The coarse aggregate of each sample was replaced with powdered glass by 20%, 30%, 40% and 100% by weight, while the cement of all samples was replaced with fly ash by 20% of its weight. It was found that as the glass waste increased, the compressive strength of the hollow block also increased. Results show that the 100% glass waste for coarse aggregate had the lowest compressive strength with an average of 739 psi, and did not meet the required compressive strength for commercial use. The hollow block with 20% glass and 20% fly ash achieved the greatest compressive strength compared to the rest of the treatments except for the commercial hollow block (POSITIVE CONTROL). The results for the water absorption capacity show that all the samples are comparable with each other except for the TREATMENT 1 (20% glass and 20% fly ash).