Preparation And Performance Of Hith Performance Concrete With Low Water Amount And Large Amounts Of Mineral Admixture

In this paper, High Performance Concrete (HPC) with low water binder ratio and large amounts of mineral admixture that owns better workability, mechanical property and durability than normal concrete (NC) are prepared successfully. The preparaed conditions were selected as follow that water to binder ratio was 0.33 cement replacement by mineral admixture were at the range of 30% to 70%, and slump of fresh concrete was over 180mm. Meanwhile, the workability, mechanical property, pore structure, the capability of anti-chloride ions and anti-carbonation of concrete of different mix proportion of mineral admixture were took into consideration; Meanwhile, many factors, which include the workability, mechanical property, the capability of anti-chloride ions and anti-carbonation of concrete of different mix proportion of mineral admixture, were taken into consideration;. Finally, functions of mineral admixture in HPC were discussed. So the effect of different mix proportion of mineral admixture on HPC can be obtained successfully.Based on the results obtained, the following conclusions can be drawn:1) By using the large amounts of mineral admixture to replace cement, while taken high efficiency water agent can be prepared the HPC which have low water binder ratio and with good fluidity.2) By mixing with large amounts of fly ash, the early hydration of cement can be accelerated at low water binder, and it is obviously quickened up at 28d and 91d;3) The raltionship of kinds and quantity of admixtures between the content of Ca(OH)₂ and the hydration period is obvisely: the fly ash can reduce the cotent of Ca(OH)₂, as a result more C-S-H were produced in HPC, which become less while mixing with silica fume and blast furnace slag.4) Mixed admixtures of fly ash, silica fume and blast furnace slag can perform better than one of them on improving the pore structure of the concrete, with the content of fly ash is 30% or 50%, the pore can be a proper diameter which below 20mm;5) When the content of fly ash increased from 0% to 50%, the capability of anti-chloride ions was increased while the capability of anti-carbonation had fallen, however, the capability of anti-chloride ions and anti-carbonation can be increased together when added two or more kinds of admixtures in the concrete.6) The advancement of increase rate of upper strength of HPC due to the decrease of Ca(OH)₂ as a result more C-S-H were produced in HPC and the improvement of pore structure of concrete primarily.