Pengaruh Paparan Temperatur Tinggi terhadap Sifat Mekanik Beton Mutu Tinggi dengan Subtitusi Flyash

Abstract

High-strength concrete is defined as concrete with compressive strength greater than 41.4 MPa. The workability of concrete is highly influenced by its constituents, typically composed of coarse aggregate, fine aggregate, cement, and water. Fly ash is a byproduct of coal combustion in Coal-Fired Power Plants (PLTU). Given the abundance of fly ash produced, it is expected to substitute cement as a component in concrete. In this study, cubic-shaped concrete specimens with dimensions of 5x5x5 cm were prepared with variations of 0%, 10%, 20%, 30%, 40%, and 50% fly ash content. The specimens underwent a curing process for 28 days and were then subjected to heating at temperatures of 500ºC and 1000ºC for 4 hours. To determine compressive strength values, compressive strength tests were conducted. The results indicate that at 500ºC, the highest compressive strength is achieved with 10% fly ash content, reaching a value of 34.2 MPa. At 1000ºC, the highest value is observed with 0% fly ash content, yielding a compressive strength of 15.3 MPa. Specimens begin to change color at 1000ºC, accompanied by the occurrence of hairline cracks