Effect of partial replacement of crushed aggregate with natural sand on mechanical and rheological properties of self-compacting concrete

This paper presents the results of an experimental study on the effect of crushed sand on the properties of fresh and hardened self-compacting concrete. Mixtures of self-compacting concrete have been produced with the replacement of 0%, 25%, 50%, 75% and 100 % of natural sand with crushed sand (CSS). Same coarse aggregate with crushing percentage of 75 has been used in all mixtures. Concrete grade of 450 Kg/m3 and water to cement ratio of 0.4 have been considered in the mixture designs. Workability properties of self-compacting concrete were investigated by empirical tests viz. slump flow test, T500, V-funnel and L-box height. Rheological properties of concrete mixtures do not change remarkably by replacing 25% and 50 % of natural sand with CSS but if the mixture includes more than 50 % of CSS, the rheological properties of self-compacting concrete will be influenced negatively and may endanger the applicability of the concrete. Strength tests included cube compressive strength test, flexural strength and Splitting Tensile Strength test. The hardened self-compacting concrete exhibits excellent short term strength with 25% CSS content