纤维和纳米材料改性水泥稳定道路固废的直剪力学行为

Direct shear mechanical behavior of cement stabilized road solid waste modified by fibers and nanomaterials

为了研究纤维-纳米材料对水泥稳定道路固废再生集料抗剪特性的影响,通过直剪试验对水泥稳定再生集料(CA)、聚丙烯纤维水泥稳定再生集料(PCA)、纳米氧化镁水泥稳定再生集料(MCA)、纳米二氧化硅水泥稳定再生集料(SCA)、聚丙烯纤维-纳米氧化镁水泥稳定再生集料(PMCA)和聚丙烯纤维-纳米二氧化硅水泥稳定再生集料(PSCA)的抗剪强度特性进行评价和表征.试验结果表明:各组试样的剪应力-位移曲线随着垂直压力的增加逐渐由软化型向硬化型转变;MCA、SCA、PMCA、PSCA的摩擦角比CA的摩擦角更大,PCA、MCA、SCA、PMCA、PSCA的黏聚力均大于CA.提出复合正弦-幂函数(CSP)模型,该模型可以有效地模拟软化型和硬化型应力-位移曲线,比传统模型更具适用性.建立各组试样的应力-位移关系的通用公式,该公式与实测数据拟合效果良好.

To study the effect of fiber-nano materials on the shear characteristics of cement stabilized road solid waste recycled aggregates,the shear strength characteristics of cement-stabilized recycled aggregate(CA),the polypropylene fiber cement-stabilized recycled aggregates(PCA),the nano-magnesia cement-stabilized recycled aggregate(MCA),the nano-silica cement-stabilized recycled aggregate(SCA),the polypropylene fiber-nano-magnesia cement-stabilized recycled aggregate(PMCA),and the polypropylene fiber-nano-silica cement-stabilized recycled aggregate(PSCA)were evaluated and characterized by the direct shear tests.Experimental results showed that the shear stress-displacement curve of each group of the samples gradually changed from the softening to the hardening with the increase of the vertical pressure.MCA,SCA,PMCA and PSCA showed larger friction angle than CA,and the cohesion of PCA、MCA、SCA、PMCA、PSCA was greater than that of CA.A composite sine-power function(CSP)model was proposed,which was more applicable than traditional models.And the softening and the hardening stress-displacement curves were simulated effectively by the CSP model.A general formula for the stress-displacement relationship of each group of the samples was established,and the formula fitted well with the measured data.