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对废弃混凝土进行破碎后所得的骨料称为再生骨料,按再生粗骨料掺量为40%的配比进行混凝土冻融循环试验,并结合聚丙烯纤维和引气减水剂两个配比参数对其抗冻影响机理的分析,得到不同掺量下聚丙烯纤维和引气减水剂对再生混凝土抗冻耐久性的影响,以及冻融后再生混凝土内部损伤变量的变化规律。结果表明:掺加聚丙烯纤维和引气减水剂可使设计强度等级为C30的再生混凝土达到F200以上的抗冻等级,并能有效地抑制其冻融损伤劣化,且引气减水剂的掺加效果更为明显。根据再生混凝土冻融破坏机理,进行再生混凝土冻融损伤分析并建立冻融损伤模型,模型所预测的再生混凝土损伤程度符合工程实际冻融破坏情况。
The aggregate obtained after the crushed concrete is crushed is called recycled aggregate, and the concrete is subjected to freeze-thaw cycles according to the ratio of 40% recycled coarse aggregate. The combination of polypropylene fiber and air-entraining water reducer Compared with the parameters of its antifreeze mechanism of the impact of different content of polypropylene fiber and air entraining water reducing agent on the durability of recycled concrete antifreeze, as well as freeze-thawed concrete internal damage variable changes. The results show that the recycled concrete with designed strength class C30 can achieve the frost resistance rating above F200 and the freeze-thaw damage can be effectively inhibited by the addition of polypropylene fiber and air-entraining water reducer. Addition effect is more obvious. According to the mechanism of freeze-thaw failure of recycled concrete, the freeze-thaw damage of recycled concrete is analyzed and the freeze-thaw damage model is established. The predicted damage degree of recycled concrete conforms to the actual freezing and thawing damage of the project.