摘   要：通过对掺与不掺聚丙烯纤维的高强混凝土进行不同高温作用后的劈裂抗拉强度、抗压强度试验研究，探讨高强混凝土劈裂抗拉强度、拉压比随温度变化的规律。研究结果表明，随着温度的升高，混凝土中的凝胶体不断分解，内部结构不断破坏，高温后高强混凝土脆性增大，劈裂抗拉强度降低；与未掺纤维的高强混凝土相比，相同温度作用后掺有聚丙烯纤维的高强混凝土劈裂抗拉强度略有提高，并借助X射线衍射（XRD）试验，分析高温作用前后高强混凝土内部成分的变化，初步揭示高温对混凝土力学性能影响的机理。

Abstract: Through studying on splitting tensile strength and the compressive strength of high strength concrete with polypropylene fiber and without polypropylene fiber after high temperature, the high strength concrete splitting tensile strength and compression ratio with the high temperature are analyzed. The results show that with the temperature increasing, the gel in concrete continuous got damage and internal structure of high strength concrete began to decompose, and splitting tensile strength decreased. Compared with doped fiber high strength concrete, at the same temperature’s effect, the splitting tensile strength of high concrete mixed with polypropylene fiber increased slightly, and with the aid of X-ray diffraction (XRD) test, the internal composition of high strength concrete before and after high temperature was analyzed, and the mechanism of high temperature on influence of mechanical properties of concrete was revealed.