Pemanfaatan Diatomaceous Earth sebagai Substitusi Parsial Semen pada Beton Mutu Tinggi terhadap Pengujian Kuat Lentur Beton

Abstract

The use of high-strength concrete is essential in the construction sector due to its ability to produce high compressive strengths above 55 MPa. However, the high use of cement in the production of this concrete contributes significantly to carbon emissions and production costs. To reduce this environmental impact, Diatomaceous Earth (DE), a natural material rich in silica (SiO2), is used as a partial substitute for cement. DE acts as a pozzolan, which can react with calcium hydroxide from cement hydration, forming calcium silicate hydrate (C-S-H) that strengthens concrete. This study evaluates the effect of DE substitution on flexural strength, workability, and absorption of high-strength concrete with DE variations of 3%, 6%, 9%, 12%, and 15% by weight of cement. Tests were conducted on beams measuring 15 cm x 15 cm x 60 cm after curing for 28 days. The results showed that at 3% DE substitution, the best flexural strength without DE addition was achieved with an average value of 5.20 MPa. However, at 6% and 9% substitution, the flexural strength decreased to 5.16 and 4.49 MPa due to increased porosity. And then it increased again at 12% substitution with an average value of 4.76 MPa. In addition, the workability of the concrete slightly decreased as the DE increased, but was still acceptable, while the absorption increased with higher percentage of DE.