01. Behaviour of concrete produced with cement having partial
replacement of Rice husk ash
01. Behavior of concrete produced with cement having partial replacement of Rice husk ash
ABSTRACT
Rice husk is an agricultural waste that is produced during the rice milling process. Rice husk is widely used as a fuel in several industries such as brick industry and power plant industry. After burning the rice husk as a fuel it becomes rice husk ash. The disposal of rice husk and its ash has been identified as a major problem in areas where rice production is abundance, for example, Ampara district in Sri Lanka. This study shows the utilization of Rice Husk Ash (RHA) in concrete, which is an expensive material that plays a major role in the construction industry. By conducting the laboratory experiments, this study shows that adding RHA enhances both compressive and tensile strengths of the concrete.
RHA was obtained from Hairu Bio-Energy power plant located in Ninthavur, Ampara. As-received RHA from the power plant was sieved in order to prepare two types of samples with different particles sizes. Then, different methods of quantitative chemical analysis were done on prepared RHA to identify the amount of chemical composition, and finally they were used to partially replace the cement to produce concrete with improved strength.
According to the chemical analysis, SiO2 is the major constituent presence in all the RHA samples. However, coarser RHA sample contained slightly higher SiO2 amount than the finer sample and that was around 86% by mass. X-ray Diffraction (XRD) analysis was performed on RHA to identify the crystalline silica phases. It revealed that the prepared RHA samples contained relatively a higher amount of amorphous silica than the as-received RHA, which showed more crystalline in nature. Comparatively coarser RHA showed a better crystallinity over finer RHA.
Ordinary Portland Cement (OPC) was replaced at 10%, 12.5% and 15% by weight with two RHA samples having different particle sizes. According to the test results of normalized compressive strength, 10% replacement of RHA is identified as the optimum for both sample types of RHA. In terms of split tensile strength, 12.5% replacement of finer RHA showed the highest tensile strength. It is also noticed that 10% replacement of RHA of both sample types showed a higher split tensile strength than the control sample.
Enhanced performances of OPC can be achieved with 10% replacement of OPC by RHA regardless of particle sizes. Moreover, the adverse environmental impacts associated with RHA can also be reduced by utilizing the RHA in cementitious systems.
