竹纤维沥青胶浆力学性能研究

Research on the Mechanical Properties of Bamboo Fiber Asphalt Emulsion

选择常见的慈竹纤维作为研究对象,制备不同纤维长度、不同纤维掺量的沥青胶浆试件,开展低温拉伸、低温流变、高温流变、抗剪切、抗老化性能试验,分析胶浆性能与竹纤维掺量、长度的关系。结论如下:(1)当掺量一定时,随着纤维长度的增大,胶浆拉伸峰值力表现出先上升后下降的规律,最大峰值力对应掺量为9%;(2)测力延度试验表明,添加竹纤维能够提高沥青胶浆的低温抗裂性能,长度9 mm、掺量2.0%、2.5%的纤维沥青胶浆拉伸峰值力为纯沥青的3倍以上,延度提升2.8%左右;(3)抗剪切试验表明,随着纤维掺量的增大,沥青胶浆锥入度逐渐减小,抗剪切强度逐渐增加,掺量2.5%、3.0%的沥青胶浆抗剪切强度可达300 MPa左右,为原状沥青的4.8倍以上;(4)低温流变性试验表明,随着纤维掺量的增加,劲度模量与材料脆性增大、蠕变速率减小,相比原状沥青胶浆,低温流变性在2.0%掺量时下降6.22%,但在2.5%掺量时下降16.71%;(5)抗老化性试验结果表明,老化后竹纤维胶浆弛豫时间仅0.79 ms,相比老化前峰值信号仅下降1.71%,表明竹纤维沥青在老化前后的黏稠度变化并不显著;老化后沥青延度损失率为18.7%,优于基质沥青的26.4%,车辙因子及增幅显著优于基质沥青,表明其具备较好的抗老化能力;(6)综合考虑慈竹纤维沥青胶浆的各项性能,推荐最佳掺量为2.0%、长度为9 mm。希望相关成果能够为同类研究提供指导。

The common bamboo fiber is selected as the research object to prepare asphalt emulsion specimens with different fiber lengths and fiber contents,and the low-temperature tensile strength,low-temperature rheology,high-temperature rheology,shear resistance and aging resistance tests are carried out.The relationship between emulsion properties and bamboo fiber content and length is analyzed.The conclusions are showed as follows:(1) When the content is constant,as the fiber length increases,the peak tensile force of the emulsion shows a pattern of first rising and then falling,and the maximum peak force corresponds to a content of 9%.(2) The force ductility test shows that the addition of bamboo fiber can improve the low temperature crack resistance of asphalt emulsion.The tensile peak force of fiber asphalt emulsion with a length of 9 mm,content of 2.0 % and2.5 % is more than 3 times that of pure asphalt,and the ductility increases by about 2.8 %.(3) The shear resistance test shows that as the fiber con-tent increases,the penetration depth of the asphalt emulsion gradually decreases,and the shear strength gradually increases.The shear strength of as-phalt emulsion with a content of 2.5% and 3.0% can reach 300 MPa,which is more than 4.8 times that of original asphalt.(4) The low-temperature rheological test shows that as the fiber content increases,the stiffness modulus and material brittleness increase,and the creep rate decreases.Com-pared with the original asphalt emulsion,the low-temperature rheological property of bamboo fiber asphalt emulsion with a content of 2.0% decreases by 6.22%,and decreases by 16.71% with a content of 2.5%.(5) The results of aging resistance test show that the relaxation time of bamboo fiber emulsion after aging is only 0.79 ms,which is only 1.71% lower than the peak signal before aging,indicating that the viscosity of bamboo fiber as-phalt before and after aging doesn't change significantly;After aging,the ductility loss rate of asphalt is 18.7%,which is better than that of matrix asphalt by 26.4%.The rutting factor and increase rate are significantly better than that of matrix asphalt,indicating that it has good anti-aging ability.(6) Considering the comprehensive performance of bamboo fiber asphalt emulsion,the optimal content is recommended to be 2.0% and the length is9 mm.It is hoped that the relevant achievements can provide guidance for similar research.