Effect of rice husk ash and coconut coir fiber on cement mortar: Enhancing sustainability and efficiency in buildings

Abstract

This research investigated energy efficiency, insulation properties together with strength properties and cost-effectiveness, focusing on developing a sustainable mortar. Cement: sand of 1: 2.25 (by weight) mortar with varying rice husk ash (RHA) and coconut coir (CC) fiber contents were prepared. Physical, microstructure, strength, durability, and thermal performances were experimentally examined. Life cycle assessment and cost analysis were numerically examined. Adding CC fiber reduced the longer final setting time found with the RHA-based mortar. With 20 % RHA and 0.5 % CC fiber, weight was reduced by 9.2 % (compared to the conventional mortar), promising a lightweight mortar. Flexural strength was increased by 8.6 % with 0.5 % CC fiber addition, this was further increased to 13.6 % with 10 % RHA in the mixture. 20 % RHA and 0.5 % CC fiber mortar exhibits a temperature difference of 8.7°C, whereas the conventional mortar exhibits a temperature difference of 2.5°C, indicating a reduced thermal conductivity of the RHA-CC fiber mortar. This mortar reduced the CO2 emission, energy consumption, and manufacturing cost by 17.7 %, 13.6 % and 7.0 %, respectively, indicating the sustainability. A cost-effective and energy-efficient lightweight mortar with enhanced thermal insulation and flexural strength was achieved by reinforcing the conventional mortar with 20 % RHA and 0.5 % CC fiber for the applications of dwellings.