A Study on Use of Rice Husk Ash in Concrete

Cement and fine aggregates are the major materials used in construction. Increase in the demand for these materials lead to the skyrocketing price of the construction. Due to this, the lower- and middle-income families are not able to build their own houses. There were studies about the research institutions are looking for alternatives can be used for construction to reduce the construction cost. In this regard an attempt has made to know the utilization of waste materials. In this project, Rice Husk Ash and Waste Foundry Sand were used in concrete for the replacement of cement and fine aggregate respectively. The most expensive concrete material is the binder (cement) and if such all-important expensive material is partially replaced with more natural, local and affordable material like RHA will not only take care of waste management but will also reduce the problem of high cost of concrete and housing. In this project, Rice Husk Ash which is taken from a brick kiln was used after grinding in a ball mill. Rice husk ash contains 90-95% SiO2, 1-3% K2O and < 5% un burnt carbon. Foundry sand is high quality silica sand with uniform physical characteristics. It is a By-product of ferrous and nonferrous steel industries, where sand has been used as a molding material. After the multiple usages the foundry sand it is used as land filling material. This experimental investigation was performed to evaluate the strength properties of concrete in which cement and fine aggregates were partially replaced with Rice Husk Ash and Waste Foundry Sand. Compression test, Split Tensile test, Flexural strength test and workability tests were conducted at the age of 28,56 and 90 days by replacement of river sand with different percentages (0%,10%,20%,30%,40%,50%and 60%) and also with 10% incorporating with rice husk ash. Compressive strength test was carried out on cement mortar cubes to know the optimum percentage of rice husk ash. The results indicate effective use of rice husk ash and waste foundry sand as partial replacement of cement and fine aggregate. However, the percentage of rice husk ash is limited to 10% and waste foundry sand is up to 40%. After these limitations the strength started decreasing. And also, the concrete incorporating with rice husk ash showed better workability than plain concrete with inclusion of waste foundry sand.