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为了促进聚乙烯醇(PVA)纤维增强水泥基复合材料(PVA-ECC)在热环境工程领域中的应用,通过狗骨试件拉伸试验,研究了高粉煤灰掺量的PVA-ECC热处理后的力学性能变化;采用单纤维抗拉试验、单纤维拔出试验以及单裂缝拉伸试验研究了PVA-ECC性能提升的机制。结果表明:在不高于200℃的热处理后,PVA-ECC仍能实现多裂缝开裂,相比20℃,50、100、200℃热处理后的PVA-ECC复合材料的拉伸力学性能提高,其幅度为100℃>50℃>200℃;纤维强度不是PVA-ECC抗拉性能变化的控制因素,适当的温度处理提高了纤维与基体的化学黏结力和摩擦力,从而提高了纤维的桥接作用和裂缝的余能,进而提高了PVA-ECC的抗拉性能和摩擦耗能能力。PVA-ECC性能变化的机制分析为PVA-ECC工程设计提供了良好的理论基础。
In order to promote the application of polyvinyl alcohol (PVA) fiber reinforced cement-based composites (PVA-ECC) in thermal environment engineering, the high-fly ash content PVA-ECC heat treatment The mechanical properties of PVA-ECC were studied. The tensile properties of PVA-ECC were investigated by single fiber tensile test, single fiber pull-out test and single-slit tensile test. The results show that PVA-ECC can still achieve multi-fracture cracking after heat treatment at 200 ℃ or above. Compared with 20 ℃, the tensile mechanical properties of PVA-ECC composite after heat treatment at 50,100 and 200 ℃ are improved, The range of temperature is 100 ℃> 50 ℃> 200 ℃. The fiber strength is not the controlling factor of the tensile properties of PVA-ECC. Appropriate temperature treatment can improve the chemical bond and friction of fiber and matrix, The residual energy of cracks, thereby improving the tensile properties of PVA-ECC and friction energy consumption. The mechanism analysis of PVA-ECC performance changes provides a good theoretical basis for the engineering design of PVA-ECC.