Utilization of Kepah clam shell in Batu Bara waste as a partial cement replacement in the production of porous concrete

Abstract

The study aims to determine the effectiveness of kepah clam shell waste from Batu Bara regency, north Sumatra province, Indonesia, as a partial replacement for cement in porous concrete production. The concrete production process follows the ACI 522R-10 method with cylindrical samples (15 cm in diameter and 30 cm in height) and a curing period of 28 days, using partial cement replacement with variations of 5%, 10%, and 15% kepah clam shells. The XRF and FTIR characterization results of the kepah clam shells indicate that the highest dominant compound is CaO at 94.68%, which can enhance concrete quality. The main composition of this material consists of calcium carbonate in the form of aragonite and calcite, along with minor organic compounds and moisture content. SEM average particle size of approximately 10.79 µm for normal concrete and 14.97 µm for concrete mixture with 15% kepah clam shell. Porosity and compressive strength tests of porous concrete show that the higher the percentage of kepah clam shell mixture in the concrete, the porosity and compressive strength also increase, reaching values of 22% and 17.76 MPa, respectively. The addition of 5% kepah clam shells can improve the split tensile strength. Optimal management of kepah clam shells can prevent negative environmental impacts and provide economic benefits to the community. Additionally, the potential use of shell powder can significantly enhance concrete strength due to its mineral content. Therefore, this study contributes to sustainable concrete technology innovation, as it addresses water absorption issues and enables efficient water infiltration into the soil.