Abstract
Packing state of cement considerably affects the fluidity of cement paste and mortar. In this study, designing of the optimum cement for high strength concrete is conducted, adjusting the particle size distribution of cement to raise the packing ratio and to enable the concrete mixing at a lower water-cement ratio. Highly packed cement produced by adjusting the fineness of clinkers exhibited higher fluidity, and the fluidity was found to have good correlation with the packing ratio of the cement. The cement produced by mixing silica fume to low-heat Portland cement was found most packed when the silica fume content was 17.5mass%. This kind of cement also exhibited higher fluidity at higher packing rates, and the most packed cement achieved the maximum compressive strength under the same fluidity conditions. The compressive strength was over 170N/mm2 in the clinker-adjusted cement and over 210N/mm2 in the silica fume-added cement at 91 days of water curing at 20℃.
