The Synergetic Effect of Fly Ash Concrete Mixed With Coconut Husk Ash for the Application of Sustainable Construction

Faculty of Applied Sciences and Technology, Universiti Tun Hussein Onn Malaysia, 84600, Pagoh, Johor.

^* Corresponding author: sitiamira@uthm.edu.my

Abstract

Cement production has increased as cement is a crucial building material for residential and infrastructural development. However, cement production has become one of the significant contributors to environmental pollution as carbon dioxide emissions come from all stages of cement manufacturing. This encouraged researchers to look into industrial and agricultural wastes as partial replacements for cement. This research study investigated the synergetic effect of using fly ash (FA) from industrial waste and coconut husk ash (CHA) from agricultural waste as a mix into concrete, enhancing concrete properties and as an eco-friendly building material. Four series of concrete sample mixes were prepared, incorporating fly ash and coconut husk ash, beginning with a reference mix as the baseline, (M0): 0% FA + 0% CHA, then (M1): 10% FA + 5% CHA, (M2): 20% FA+ 10% CHA and (M3): 30% FA + 15% CHA as cement replacement were designed. The ratio of cement to sand was fixed at 1:1, where the cement content was gradually decreased and substituted with fly ash and coconut husk ash content, and the amount of water per cement ratio was fixed at 0.5. After 24 hours of hydration, the hardened concrete samples were water-cured for 3, 7 and 14 days before performing density, water absorption, and compressive strength tests. The sample morphology was examined using a field scanning electron microscope (FESEM). Results show that the incorporation of fly ash and coconut husk ash does not increase the compressive strength of concrete. The results of the density test, water absorption test, and concrete morphology were presented. Although the concrete strength was not achieved, the results suggest using a superplasticiser as a reducing agent to reduce cement bleeding and improve concrete strength.