冻融循环与海水腐蚀对超高性能混凝土抗冲磨性能的影响研究

Influence of Freeze-thaw Cycles and Sea Water Corrosion on the Abrasion Resistance of Ultra-high Performance Concrete

北方沿海地区水电工程的过流面在冻融循环以及海水腐蚀条件下遭受大粒径推移质泥沙的冲磨破坏,严重影响水电工程的正常运行。本文针对上述问题,采用水下钢球法的混凝土抗冲磨试验方法开展超高性能混凝土(UHPC)的抗冲磨性能研究。以橡胶颗粒掺量、冻融循环次数、海水腐蚀天数为主要参数,以C50钢纤维混凝土为对比试件,测定了各组试件的抗冲磨强度,初步探索了橡胶颗粒掺量、冻融循环、海水腐蚀和冻融循环与海水腐蚀的耦合作用对UHPC抗冲磨性能的影响,结果表明,橡胶颗粒掺量为10%的UHPC抗冲磨强度最佳;在冻融循环超过150次时,UHPC的抗冲磨强度随着冻融循环次数的增加逐渐降低;在海水腐蚀超过50d时,UHPC的抗冲磨强度随着海水腐蚀天数的增加逐渐降低;在冻融循环和海水腐蚀耦合作用下,掺10%橡胶颗粒的UHPC抗冲磨强度约为C50钢纤维混凝土的28倍。采用UHPC制备抗冲磨混凝土是一种提高北方沿海地区水利工程建筑物抗冲磨性能的有效方法。

Flow surface of hydroelectric project at northern coastal region is subject to abrasion damage of large particle size bedload silt under the condition of freeze-thaw cycles and sea water corrosion,which seriously affects the normal operation of hydroelectric project.Based on the above issue,the abrasion resistance of UHPC(Ultra-high performance concrete)was studied by underwater steel ball method.The abrasion resistances of UHPC and the contrast specimen of C50 steel fiber reinforced concrete were determined under the main parameters of rubber particlescontent,freezethaw cycles and the sea water corrosion days,and the effects ofrubber particles content,freeze-thaw cycles and sea water corrosion on the abrasion resistance of UHPC were discussed.The experiment results indicate that,the abrasion resistance of UHPC is the best with 10%content of rubber particles;the abrasion resistance of UHPC decreases gradually with the increase of freeze-thaw cycles when the freeze-thaw cycles exceed 150;the abrasion resistance of UHPC decreases gradually with the increase of sea water corrosion days when the sea water corrosion days exceed 50;the abrasion resistance of UHPC with 10%content of rubber particles is 28 times than that of the C50 steel fiber reinforced concrete under the combined effect of freeze-thaw cycles and sea water corrosion.Abrasion resistance of the hydroelectric project at northern coastal region will be improved by the abrasion resistant concrete prepared by UHPC.