Kuat Tekan dan Kuat Lentur Beton dengan Bahan Tambah Fly Ash sebagai Bahan Perkerasan Kaku (Rigid Pavement)

Abstract

Concrete, as the main construction material, has weaknesses such as high porosity and long-term strength reduction if not modified with additives. One widely studied solution is the use of fly ash as a pozzolanic material that can improve concrete performance while reducing dependence on cement. This study aims to determine the effect of varying fly ash additions on the mechanical properties of concrete, particularly compressive strength and flexural strength at the ages of 7, 28, and 54 days. The fly ash variations used were 0% (normal concrete), 15%, 20%, and 25% of the total cement usage. The research method applied was a laboratory experiment by preparing test specimens in the form of cylinders and beams, which were then tested using ASTM and PBI 1971 standards. The results showed that concrete with fly ash addition significantly improved compressive and flexural strength, especially at 28–54 days. Concrete with 20% fly ash exhibited the best performance, achieving a compressive strength of 35.8 MPa and a flexural strength of 5.3 MPa at 54 days. The 15% variation still demonstrated a considerable increase, whereas the use of 25% fly ash tended to reduce strength compared to the 15% and 20% variations.