Influence of silica fume and superplasticizer on compressive strength and flow diameter of high performance concrete

In producing high-performance concrete(HPC),the components of silica fume and superplasticizer couldcan improve the cementitious hydration and reduce water-cement ratio.Therefore,finding the optimum mix proportion of these two additives is the a key procedure issue to achieve high mechanical performance and workability of the HPC.In this paper,the optimal mix proportions of silica fume and superplasticizer in HPC have been investigated by comparing the flowability and 28-day compressive strength with thea fixed water-cement ratio of 0.15 by the comparison in flowability and 28-day compressive strength.The mass proportion of superplasticizer and the cementitious replacement percentage of silica fume were used in the range of 0.3%~2.0% and 8%~20%,respectively.The results showed that,the flowability of the fresh HPC reached the climax in when the mass proportion of superplasticizer was 1.5% of superplasticizer,and the flowability deteriorated decreased with the increasing of the cementitious replacement percentage of silica fume;the compressive strength of the hardened HPC reduced decreased compressive strength with the increasing of the content of super-plasticizer,and the maximum compressive strength was obtained within when the silica fume cementitious replacement was 10%.With the optimized mix design of content of silica fume of(10%) and super-plasticizer content of(1.1%),the HPC achieved 170mm in flow diameter and 93MPa at the age of 28 days under 20℃curing.