Study on Compressive Strength of Eco-Friendly Concrete Utilizing Brick Powder from Oebelo as Pozzolanic Material

Abstract

Brick production waste in Oebelo Village, Kupang Regency, which reaches approximately 30% of total production, poses a potential environmental pollution threat. This study examines the utilization of brick powder (SBB) waste as a pozzolanic material for partial cement substitution in eco-friendly concrete mixtures. Laboratory test results indicate that Oebelo SBB has a cumulative active oxide content (SiO₂ + Al₂O₃ + Fe₂O₃) of 91.17%, exceeding the minimum pozzolanic-material requirement referenced in ASTM C618. Concrete cylinder compressive strength testing refers to structural requirements under SNI 2847:2019, with SBB substitution variations of 0%, 10%, 20%, and 30% and a constant water-cement ratio (w/c) of 0.5. Testing was conducted at curing ages of 28, 56, and 90 days to observe long-term pozzolanic reaction kinetics. The findings demonstrate that 10% SBB substitution achieves the best compressive strength among the substitution mixtures, reaching 34.5 MPa at 90 days, equivalent to 96.64% (approximately 97%) of the control concrete strength of 35.7 MPa. The utilization of SBB as a pozzolanic material therefore shows potential to support lower-cement concrete production while providing a practical pathway for local brick-waste utilization. Further durability and field-scale evaluation is recommended before broad structural application.