Analisis Korelasi Dan Sifat Mekanis Kuat Tekan-Lentur Beton Dengan Penambahan Spent Bleaching Earth (SBE) Dan Cangkang Kerang Terhadap Substitusi Semen

The increasing demand for concrete production leads to excessive cement consumption, contributing to natural resource depletion and high carbon emissions. To address this issue, the use of industrial waste such as Spent Bleaching Earth (SBE)—a byproduct of palm oil refining—and seashells rich in calcium oxide (CaO), offers a sustainable alternative as partial cement substitutes. This research
aims to analyze the effect of adding 10% SBE and seashell powder on the compressive and flexural strength of concrete, as well as to evaluate the correlation between both properties. The experimental method involved concrete samples treated with freshwater and seawater, with tests
conducted at 7, 28, and 56 days. The results showed that normal concrete cured with freshwater achieved the highest compressive strength of 33.90 MPa and a flexural strength of 4.00 MPa. Meanwhile, concrete mixed with SBE and seashells cured in seawater demonstrated the strongest correlation between compressive and flexural strength (R² = 0.8771), while normal concrete with seawater had the weakest correlation (R² = 0.0443). In conclusion, the use of SBE and seashells can effectively enhance the mechanical performance of concrete, especially in marine environments, and supports the development of eco-friendly concrete.