不同种类纤维加筋水泥改良风积沙抗拉性能试验研究

Experiment on the splitting tensile strength of cemented aeolian sand reinforced with different kinds of fibers

为研究不同种类纤维对水泥改良风积沙劈裂抗拉强度及峰值应变的影响,开展纤维水泥改良风积沙的劈裂抗拉强度试验。试验选用玄武岩纤维、聚丙烯纤维、玻璃纤维和聚酯纤维等4种常用纤维加筋水泥改良风积沙,水泥掺量为5%,纤维掺量为0,2‰,4‰,6‰,8‰,10‰和12‰,未掺纤维的水泥改良风积沙作为对照组。研究结果表明:纤维水泥改良风积沙应力应变曲线起始段近似线性增加,达到峰值强度后,峰后曲线缓慢下降,残余强度随着纤维掺量的增加而增大。聚丙烯纤维、玄武岩纤维、玻璃纤维和聚酯纤维加筋水泥改良风积沙劈裂抗拉强度最大值分别为77.65,67.86,64.49和63.41 kPa,峰值应变分别为1.05%,0.94%,0.82%和0.75%,对应的最优纤维掺量分别为8‰,8‰,4‰和6‰,而水泥改良风积沙的劈裂抗拉强度为53.0 kPa,峰值应变为0.63%,与未掺纤维的水泥改良风积沙相比,聚丙烯纤维、玄武岩纤维、玻璃纤维和聚酯纤维加筋水泥改良风积沙的劈裂抗拉强度的强度增强比为1.47,1.28,1.22和1.20,劈裂抗拉强度最优掺量下的延性指数分别为1.67,1.49,1.30及1.19,纤维增大了水泥改良风积沙的劈裂抗拉强度,增强其延性,聚丙烯纤维水泥改良风积沙对劈裂抗拉强度的影响最显著。研究成果可为风积沙铁路路基基床填料改良提供参考。

The main objective of this work was to study the influence of different kinds of fibers on the splitting tensile strength and peak strain of cemented aeolian sand reinforced with fiber,the splitting tensile strength(STS)tests of cemented aeolian sand reinforced with fiber were carried out.The 5%cement and four kinds of fibers were mixed with aeolian sand to create the cemented aeolian sand specimens reinforced with fiber contents of 0,2‰,4‰,6‰,8‰,10‰,and 12‰.The different four fiber types used included basalt fiber,polypropylene fiber,glass fiber and polyester fiber,the cemented aeolian sand without fiber was used as the control group.The results show that the initial section of the stress-strain curve of cemented aeolian sand reinforced with fiber increases approximately linearly.After reaching the peak strength,the post-peak curve decreases slowly,and the residual strength increases with fiber content.The splitting tensile strength of cemented aeolian sand without fiber is 53.0 kPa,the peak strain is 0.63%.The fiber content of the maximum splitting tensile strength of cemented aeolian sand reinforced with polypropylene fiber,basalt fiber,glass fiber and polyester fiber is 8‰,8‰,4‰and 6‰respectively,the corresponding maximum splitting tensile strength is 77.65,67.86,64.49 and 63.41 kPa respectively,and the corresponding peak strains are 1.05%,0.94%,0.82%,0.75%.The ratio of the STS of cemented aeolian sand specimens reinforced with polypropylene fiber,or basalt fiber,or glass fiber,or polyester fiber to that of cemented aeolian sand specimens without fiber is 1.47,1.28,1.22,and 1.20.The value of ductility index of cemented aeolian sand specimens reinforced with polypropylene fiber,or basalt fiber,or glass fiber,or polyester fiber is 1.67,1.49,1.30,and 1.19.Therefore,the splitting tensile strength and ductility of cemented aeolian sand reinforced with fiber are increased.The research results can provide reference to stabilize aeolian sand for railway roadbed filling.