Effect of Sand to Aggregate Ratio on the Properties of Self-Compacting High-Performance Concrete

- Self-compacting high-performance concrete (SCHPC) combines the properties and advantages of self-compacting concrete and high-performance concrete in both fresh and hardened states. For the SCHPC mix design, sand to aggregate ratio is a crucial parameter and plays an important role in governing the properties of SCHPC mix. This paper presents the results of an experimental investigation on the flowability, passing ability and mechanical properties of SCHPC mixes for various sand to total aggregate (S/A) ratio and water to cementitious material (w/cm) ratio. Tests were conducted on specimens using four (w/cm) ratios: 0.26, 0.30, 0.35 and 0.40 and two (S/A) ratios: 48% and 53%. All the mixtures were tested using slump flow test, J-Ring test, and L-box test in the fresh state as well as compressive strength, splitting tensile strength, and unit weight in the hardened state. The test results revealed that a lower S/A ratio (0.48) enhanced the flowability whereas the higher S/A ratio (0.53) enhanced the passing ability. The lower S/A ratio (0.48), containing greater proportion of coarse aggregate, generally improved the mechanical properties of SCHPC compared to the mixes with the higher S/A ratio (0.53).