Pengaruh Pemanfaatan Komposit SBE-Semen Hasil Prakondisi sebagai Material Substitusi Parsial Semen terhadap Kuat Tekan dan Susut Beton

This study aims to analyze the effect of utilizing preconditioned Spent Bleaching Earth (SBE)–cement composite as a partial cement replacement material on the compressive strength and shrinkage of concrete, as well as to determine the optimum substitution percentage. The SBE was first sieved using a No. 200 sieve and then mixed with cement at substitution levels of 5%, 7.5%, 10%, and 12.5%. The research employed an experimental method using normal concrete as the control mixture. Compressive strength tests were conducted on cylindrical specimens at the ages of 7 and 28 days, while shrinkage tests were carried out by observing the length changes of the specimens up to 72 hours. The data were analyzed using descriptive statistics, normality tests, Pearson correlation, and simple linear regression with the aid of IBM SPSS Statistics. The results showed that the 5% SBE mixture produced the highest compressive strength among all composite variations, reaching 31.50 MPa at 7 days and 20.30 MPa at 28 days, while normal concrete achieved the highest compressive strength at 28 days, with an average value of 28.33 MPa. Statistical analysis indicated that the SBE percentage had no significant effect on the compressive strength of concrete at 7 days but had a significant negative effect at 28 days. In the shrinkage test, the 7.5% SBE mixture exhibited the highest shrinkage value of 0.222 after 72 hours, and the SBE percentage showed a positive and significant relationship with concrete shrinkage. Overall, the 5% SBE mixture was identified as the optimum substitution level among all preconditioned SBE–cement composite mixtures investigated.