Performance Monitoring on Using Reactive Perlis Rice Husk Ash as Partial Mortar Replacement

Cement industry is a major carbon dioxide emission contributor, which could be reduced by implementing supplementary cementitious materials. Rice husk ash (RHA) exhibits high pozzolanic characteristics when properly produced using controlled incineration. In this study, rice husk (RH) collected from rice milling industry in Perlis, Malaysia was burned at 650 °C for 1 hour. The completed burning process produced dark-grey 78 μm sized amorphous ash particles containing almost 89% silica content. To understand the compressive strength in early age mortar, varying composition of RHA between 5 to 20% was purposely replaced with OPC. It was found that replacing RHA at 5% produced the highest strength followed by RHA replacement up to 15% in relation to the conventional OPC mortar. However, adding up to 20 % results in a steep decrease in the compressive strength due to the densification and space ratio factors in the mortar. In addition, the environmental performance of 20% RHA mixture were unsatisfactory as it is associated with the control mixture. In conclusion, mortar containing 5% RHA replacement shows acceptable properties similar to conventional cement mortar. Further analysis needs to be carried out to understand the hydration mechanism that affected their performance.