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The proposed method is to replase some part of cement in the specimens with silica(Ottawa sand), By dint of the CaO and SiO2 of cement and silica being heat-reaction through high temperature steam-injection process, and that produced high-strength tobermorite. The testing variable includes: the percentage of silica, temperature(pressure), hydration duration and preset. Meanwhile, We gain the hydration degress and cement of Ca(OH)2 through the SEM and method of loss of ignition and compressive strength after hardening to understand hydration Mechanisms and strength growth. Because the Potland Concrete under high-temperature and high-pressure steam has the advantage of early-stage strength and dense-structure; and if there exists extra SiO2 under this catalysis condition, the original hydration produce will be improved, and its strength and durability will be higher. The silica added in cementsand paste just can serve as the source of SiO2, Hence, cement-sand paste through high-temperature and high-pressure steam-injection process. All cement-sand paste cubes(5cm) made by exposing wet mixes to 180℃ steams for 12 hours hydration duration and 2 hours preset developed strength greater than 1635kg/cm2.
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