The influence of cement substitution with rice husk ash on high-strength concrete

¹ Civil Engineering Department, Politeknik Negeri Padang, West Sumatera, Padang, Indonesia
² Civil Engineering Department, Engineering Faculty, Universitas Andalas, West Sumatera, Padang, Indonesia

^* Corresponding author: dwina@pnp.ac.id

Abstract

High-strength concrete is a crucial construction material in modern infrastructure development. It involves replacing some conventional raw materials with environmentally friendly alternatives to enhance concrete quality. Rice husk ash (RHA) is an agricultural waste that contains natural pozzolanic materials capable of improving the mechanical properties and strength of concrete. The use of rice husk ash (RHA) in high-strength concrete mixtures has the potential to reduce cement consumption and enhance crack resistance. The aim of this study is to investigate the impact of substituting cement with rice husk ash (RHA) and adding superplasticizer on the compressive strength of concrete. The targeted concrete strength is 45 MPa with variations of rice husk ash substitution at 5%, 10%, and 15% by weight of cement. This research obtained the compressive strength of concrete at 7 days with variations of 5% at 30.59 MPa, 10% at 25.20 MPa, and 15% at 20.77 MPa. Subsequently, at 14 days, the compressive strength increased with variations of 5% at 37.48 MPa, 10% at 27.56 MPa, and 15% at 22.23 MPa. The compressive strength continued to rise at 28 days, with variations of 5% at 44.26 MPa, 10% at 29.36 MPa, and 15% at 29.19 MPa.