Analisis Korelasi Kuat Tekan-Lentur Beton Menggunakan Spent Bleaching Earth & Cangkang Kerang Sebagai Material Substitusi Semen Pada Dua Metode Perawatan

The use of concrete as a construction material continues to increase in line with development, but concrete production is still dependent on cement as a binder. Cement production has an environmental impact because it contributes to global carbon dioxide (CO2) emissions. Therefore, environmentally friendly material innovations are needed. This study analyzes the effect of substituting cement with Spent Bleaching Earth and shell fragments on the mechanical properties of concrete, particularly the relationship between compressive strength and flexural strength. The use of these two materials as cement substitutes is an effort to reduce waste, decrease cement usage, and create innovative environmentally friendly concrete. The concrete was tested under two immersion conditions. Cylindrical specimens were used for compressive strength testing at 7, 28, and 56 days, while beams were used for flexural strength testing at 28 days. The research results show that the addition of SBE (Spent Bleaching Earth) and 7.5% shell produced at 28 days, a compressive strength of 30.79 MPa for freshwater curing and 31.13 MPa for seawater curing, and a flexural strength of 6.0 MPa for freshwater curing and 5.8 MPa, for seawater curing, which are higher than those of normal concrete. There is a fairly strong correlative relationship between compressive strength and flexural strength in concrete with added SBE (Spent Bleaching Earth) and shell fragments in two types of immersion, with an R² >0.85, meaning that more than 85% of the variation in flexural strength can be explained by the variation in compressive strength. This demonstrates the potential for the use of this combination of substitute materials in sustainable construction