Analisis Perbandingan Nilai Kuat Tekan dan Kuat Lentur Beton Dengan Penambahan Limbah Cangkang Kerang Dan Spent Bleaching Earth sebagai substitusi pada dua Metode perawatan

This study aims to analyze the effect of cement substitution with the addition of Spent Bleaching Earth (SBE) and shell shells with a comparison of actual and theoretical coefficients tested against the compressive strength and flexural strength of concrete in two types of immersion water, namely fresh water and sea water, with a percentage of 10% of the cement weight. The results show that the compressive strength of concrete with the addition of shell fragments and Spent Bleaching Earth in seawater increases with age but has not yet reached the planned quality, with an increase from 7 to 28 days (23.77%) and from 28 to 56 days (1.38%). Meanwhile, in freshwater, the increase from age 7 to 28 was 30.07%, and from 28 to 56, it decreased by 15.24%. This means that the addition of BCK+SBE is not effective in seawater but is effective in freshwater, though not over the long term. Conversely, the flexural strength of the concrete remains stable and even tends to increase, especially in seawater, reaching 5.7 MPa, and the flexural strength-to-compressive strength ratio exceeds the standard, particularly for BCK+SBE in seawater (1.18). This indicates that the concrete exhibits excellent structural performance even in waste-based mixtures