A Brief Study on Effect of Used Foundry Sand and Mineral Admixtures on Strength Properties of Concrete

Abstract

Sand has been used for centuries as a moulding material in ferrous and non-ferrous metal casting industries because of its thermal conductivity. Foundries successfully recycle and reuse the sand many times in a foundry. When the sand can no longer be reused in the foundry, it is removed from the foundry and is termed as USED FOUNDRY SAND (UFS) or WASTE FOUNDRY SAND (WFS). This used foundry sand waste can be utilized for the preparation of concrete as partial replacement of sand. In order to explore the possibility of utilizing the used foundry sand as partial replacement to fine aggregate, an experimental investigation has been carried out. The strength properties such as Compressive, Split tensile and Flexural strengths of M25 grade concrete are studied with different percentage replacement of fine aggregate by used foundry sand for 0%, 10%, 20%, 30%, 40%, and 50%. The optimum percentage of used foundry sand in concrete corresponding to maximum strength will be identified. Keeping this optimum percentage of used foundry sand replacement as constant, cement replacement study with admixtures such as silica fume (5%,7.5%,10%,12.5%)and fly ash (5%,10%,15%,20%,) are carried out separately on strength properties of concrete. With the above study, the maximum strength of concrete corresponding to replacement of silica fume and fly ash are identified. It was observed that the maximum increase in strength properties compared to conventional concrete was achieved at 40% replacement of used foundry sand. Based on the results obtained, the replacement of 40% used foundry sand with silica fume showed better performance than with Fly ash .Among all the mixes the maximum increase in strengths were observed in a mix which consist of 40% used foundry sand with 10% silica fume. The details of the investigation along with the results are present in this report.