The impact of using rice husk ash as a replacement material in concrete: An experimental study

Rice husk ash (RHA) is a promising pozzolanic alternative material for partial replacement of ordinary Portland cement to increase the durability and strength of concrete and, at the same time, to decrease the corrosion effect caused by the harsh environment conditions. In this study, the impact of adding RHA in different ratios (0%, 7%, and 14%) as a replacement of ordinary Portland cement with different water–cement ratios (0.3, 0.5, and 0.7) and cured in water for different periods (10, 20, and 30 days) both on the durability and strength of the concrete and on its corrosion was investigated. The prepared specimens were tested by flexural, compressive, and tensile strength tests, slump test, and Rapid Chloride Ion Penetration test to determine the suitability of the partial replacement of ordinary Portland cement by RHA in concrete. The most important findings of this work, which is considered novel in this field, are that adding fine (instead of more extensive) RHA particles enhances the flexural, compressive, and tensile strength values and limits the chloride ion penetration with time. An adverse impact was found to increase the water–cement ratio, which is assigned to the effect of water on RHA and as a result on the porosity of the concrete.