Abstract
To achieve high fluidity of fresh mortar and high compressive strength of hardened mortar in ternary blended cement systems for ultrahigh strength concrete, the influences of particle composition and curing temperature on mortar were examined. The ternary blended cement was produced by mixing moderate heat Portland cement as the coarse grain, silica fume as the fine grain and silica fine powder as the intermediate grain. Curing temperature was between 20℃ and 90℃. The flow value of fresh mortar and the compressive strength of hardened mortar were found to increase when the specific surface of silica fume was reduced from 20m2/g to 10m2/g. It was also found that high performance was achieved when a cement system consisting of 60vol.% of moderate heat Portland cement, 20vol.% of silica fine powder and 20vol.% of silica fume with a specific surface of 10m2/g was used, although the ratio of intermediate particles was higher than that calculated according to the theory of particle packing by Furnas. The other finding was that pozzolanic reaction was accelerated with the increase in the curing temperature, resulting in a reduced porosity. However, there was no obvious influence of the specific surface of silica fume on cement hydration and pozzolanic reaction.
