多场耦合作用下聚丙稀纤维不同掺量对混凝土耐久性影响分析

Analysis of durability of concrete subjected to polypropylene fiber addition field corrosion coupling

为研究碳化环境、冻融循环和碳化-冻融耦合作用下的混凝土耐久性性能变化规律,在混凝土中配制了不同质量分数的聚丙烯纤维进行测试分析。试验结果显示:在单一碳化环境下,随着聚丙烯纤维掺量的增加,混凝土的碳化深度呈现先减小而后增加的变化规律,其最佳掺量为2%;在单一冻融环境下,随着聚丙烯纤维掺量的增加,混凝土的抗压强度呈现先增大而后减小的变化规律,其最佳掺量也为2%;在耦合环境作用下,混凝土的抗碳化性能和抗冻融性能相较于单一循环作用都要小。在相同的碳化循环下,冻融循环次数对混凝土的抗碳化性能影响很大;在相同的冻融循环下,碳化循环次数对混凝土的抗冻融性能影响较小。耦合环境作用会对混凝土的耐久性性能影响更大,在配制高性能混凝土中需要着重关注耦合作用对混凝土耐久性能的影响。

In order to study the change rule of concrete durability under carbonation environment,freeze-thaw cycle and carbonation freeze-thaw coupling action,polypropylene fiber with different content was prepared in concrete for test and analysis.The test results show that in the single carbonation environment,with the increase of polypropylene fiber content,the carbonation depth of concrete presents the change rule of first decreasing and then increasing,and the best content is 2%;in the single freeze-thaw environment,with the increase of polypropylene fiber content,the compressive strength of concrete presents the change rule of first increasing and then decreasing,and the best content is 2%;in the coupling environment,the carbonation resistance and freeze-thaw resistance of concrete are smaller than that of single cycle.Under the same carbonation cycle,the number of freeze-thaw cycles has a great influence on the carbonation resistance of concrete.Under the same freeze-thaw cycle,the number of carbonation cycles has little effect on the freeze-thaw resistance of concrete.Coupling environmental effect will have a greater impact on the durability of concrete.In the preparation of high performance concrete,it is necessary to pay attention to the effect of coupling on the durability of concrete.