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文章通过三点弯曲切口梁试验,考察了纤维掺量对聚丙烯纤维增韧水泥浆(PPFRCP)荷载位移曲线、断裂韧度和断裂能的影响,并与普通水泥基注浆材料进行了对比。结果表明,聚丙烯纤维的掺入改变了水泥基注浆材料的破坏特征,赋予了注浆材料优良的阻裂增韧能力,裂后残余荷载、断裂韧度及断裂能均显著增强。聚丙烯纤维体积掺量为0.1%~0.4%时,PPFRCP的裂后残余荷载可达其峰值荷载的20%~40%左右,断裂韧度相对普通水泥基材料提高23%~31%,断裂能相对提高179%~459%。在满足注浆施工流动性要求的前提下,掺入高体积掺量聚丙烯纤维,更有利于增强PPFRCP注浆材料的阻裂能力和裂后工作韧性。
The effect of fiber content on load-displacement curve, fracture toughness and fracture energy of polypropylene fiber toughened cement slurry (PPFRCP) was investigated by three-point bending incision beam test, and compared with ordinary cement-based grouting material. The results show that the incorporation of polypropylene fibers changes the failure characteristics of cement-based grouting material and gives the grouting material excellent resistance to cracking and toughening. Residual load, fracture toughness and fracture energy of the grouting material are significantly enhanced. When the volume fraction of polypropylene fiber is 0.1% ~ 0.4%, the post-cracking residual load of PPFRCP can reach about 20% ~ 40% of its peak load, and the fracture toughness is increased by 23% ~ 31% with respect to ordinary cement-based materials. A relative increase of 179% ~ 459%. Under the premise of meeting the fluidity requirements of grouting construction, the incorporation of high volume content of polypropylene fiber is more conducive to enhancing the crack resistance and post-crack work toughness of PPFRCP grouting material.