Utilization of treated saw dust in concrete as partial replacement of natural sand

Abstract

The mining of natural material such as sand on large scale for use in construction of infrastructure in developing countries like India is posing threat to the environment. To save the environment, therefore, it becomes obligatory on the part of researcher to explore the utilization of industry by-products in place of natural material. In this study utilization of saw dust generated by wood industry in concrete has been explored. This article presents properties of concrete using different percentage of water and sodium silicate treated saw dust as replacement of sand. Saw dust passing through 4.75 sieve was treated with water and sodium silicate for 24 h before using in concrete. Natural sand was replaced with 5, 10,15 and 20% water treated saw dust in concrete mixture. The effect of silica fume on properties of concrete containing 5% water treated saw dust was also studied by replacing 4, 8 and 12% cement with silica fume in concrete. It was observed that concrete made with 5% water or sodium silicate treated saw dust displayed compressive strength comparable to that of control concrete. However, for 10% replacement level, compressive strength and split tensile strength decreased by 30.30% and 32.19% respectively, at 28 days. Total charge passed, water penetration and capillary water absorption increased by 224%, 153% and 117.4%, respectively, on use of 10% treated saw dust. The concrete mixture modified with sodium silicate treated saw dust showed remarkable improvement in respect of resistance to chloride ion penetration. As expected, the results showed considerable decrease in density of concrete with the use of saw dust as replacement of sand. Addition of sodium silicate treated saw dust resulted in ettringite formation in large quantity in concrete.