Optimasi Campuran Beton Menggunakan Pasir Pantai, Fly Ash, dan Bottom Ash terhadap Mutu Beton dengan Metode Eksperimental Berdasarkan SNI

Abstract

The limited availability of natural aggregates and the increasing amount of industrial waste, particularly fly ash and bottom ash, have encouraged the exploration of alternative materials for concrete mixtures that comply with Indonesian National Standard (SNI) requirements. Beach sand can be utilized as a substitute for fine aggregate after appropriate processing, while fly ash and bottom ash have potential as partial replacement materials in concrete composition. This study aims to analyze the effect of using beach sand, fly ash, and bottom ash on concrete quality and determine the optimal mixture proportion. The research applied a quantitative approach with an experimental method conducted at the Civil Engineering Laboratory of Universitas Muhammadiyah Parepare. The research samples included normal concrete and four modified mixture variations. Testing was carried out by evaluating slump values and compressive strength at concrete ages of 7, 14, and 28 days, with data analyzed descriptively based on laboratory test results. The results showed that the optimum mixture consisted of 25% beach sand, 10% fly ash, and 20% bottom ash, producing a slump value of 28 mm and an average compressive strength of 25.50 MPa at 28 days of curing. This value met the planned concrete quality requirement of f’c 25 MPa (K-250) based on SNI standards. Therefore, the use of beach sand, fly ash, and bottom ash can serve as an alternative concrete mixture that maintains structural performance while supporting the utilization of local materials and industrial waste.