王朝强1,2,谭克锋1,2,朱建舟3,张韶华1,2,丁文文1,2
免压蒸预应力离心桩用C80高强混凝土抗冻融和抗硫酸盐性能研究
王朝强1,2,谭克锋1,2,朱建舟3,张韶华1,2,丁文文1,2
摘 要:为探索养护制度对采用水泥-硅灰-矿渣粉复合胶凝材料的C80桩用高强混凝土耐久性性能的影响规律,研究了不同养护条件下(蒸汽养护和标准养护)C80桩用高强混凝土抗冻融和抗硫酸盐性能,并分析了不同蒸汽养护恒温静停时间对复合胶凝材料水化程度的影响。试验结果表明,蒸汽养护能有效提高预应力离心桩用C80高强混凝土早期(28d)强度;标准养护下的预应力离心桩用C80高强混凝土抗冻融和抗硫酸盐性能要优于蒸汽养护,其中水泥用量为400kg/m3,矿粉与硅灰互掺近1:1时,抗冻等级可达F450,抗硫酸盐等级可达KS150以上;蒸汽养护最高恒温不超过80℃对提高水泥基胶凝材料耐久性更加有利。
Abstract: To explore the influence of curing system on the permeability of C80 high-strength concrete which based on cement- silica fume-slag compound cementitious materials, the durability of C80 high-strength concrete under different curing conditions(steam-curing and standard curing) are studied, and the effect of different steam-curing thermostatic rest period on the hydration degree of compound cementitious materials is also studied. The results show that steam-curing is propitious to increase the strength of concrete in early age(28d). The freezing-thaw resistance and sulfate resistance of concrete under the standard curing is superior to the steam-curing, and the cement content in 400kg/m3, mineral powder and silica fume mixed close to 1:1, under these conditions, the mechanical property and working performance of the non-autoclaved C80 concrete all meet the standard requirements, the frost resistance level can reach F450, anti-sulfate corrosion performance level more than KS150. In addition, when the highest curing temperature is below 80℃, it is much better for the increase of impermeability of compound cementitious materials.
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