聚酯纤维和TB胶粉对高RAP掺量沥青混合料路用性能和自愈合性能的影响

摘要

In order to improve the road performance and anti-fatigue durability of hot recycled mixtures with high content of RAP(RAP≥25%),the effects of different TB powder dosage(14%,18%,22%)and The fatigue properties,durability and self-healing properties of the composite modified by TB rubber powder and modified RAP were studied under the condition of polyester content(0.2%,0.3%,0.4%,0.5%).The results show that the hot recycled mixture of SBS modified asphalt does not exhibit good rutting resistance and water stability under the coupling of water temperature.The road performance of the hot recycled mixture depends not only on the properties of asphalt and aggregates,The degree of integration of new and old materials and the compatibility of new asphalt and aged asphalt.The composite modifier of polyester fiber and TB rubber powder can significantly improve the high and low temperature performance and water stability of the thermal recycled mixture.When the dosage is between 0.3%~0.4% polyester fiber and 18%~22% The high and low temperature performance of the hot recycled mixture with high RAP content reached the optimum.0.3%~0.4% polyester fiber and 18%~22% TB rubber powder,the low temperature bending strain can reach 3 500~4 200 με under the heat modification mixture,and the low temperature performance of the mixture with high RAP content is overcome defect.The results show that the recovery rate of the thermal recovery mixture can reach 67.6%~76.9% in the range of 14%~18% TB powder dosage,The recovery rate of fatigue life can reach 57.6%~74.3%,and the recovery of stiffness modulus is 2.9~3.1 times and 1.9~2.2 times of that of matrix asphalt and SBS modified asphalt thermal recycled mixture.%为改善高比例RAP掺量(RAP掺量≥25%)热再生混合料的路用性能和抗疲劳耐久性,研究了不同TB胶粉掺量(14%、18%、22%)和聚酯掺量(0.2%、0.3%、0.4%、0.5%)条件下纤维TB胶粉复合改性高RAP掺量热再生混合料的路用性能、抗疲劳耐久性能和自愈合性能.结果表明,SBS改性沥青热再生混合料在水温耦合作用下并未呈现出较好的抗车辙性能和水稳定性,热再生混合料的路用性能不仅取决于沥青、集料的性能,也受新旧料交融程度及新沥青与老化沥青的配伍性.掺加聚酯纤维与TB胶粉复合改性剂可显著提高热再生混合料的高低温性能、水稳定性,在0.3%~0.4%聚酯纤维和18%~22%TB胶粉掺量时高RAP掺量热再生混合料高低温性能达到最优.0.3%~0.4%聚酯纤维与18%~22%TB胶粉复合改性方案下热再生混合料低温弯曲应变可达到3 500~4 200 με,克服了高RAP掺量热再生混合料低温性能差的技术缺陷.证明了TB胶粉对热再生混合料自愈合性能的改善效果,在14%~18%TB胶粉掺量范围内,热再生混合料的劲度模量恢复率可达67.6%~76.9%,疲劳寿命恢复率可达57.6%~74.3%,劲度模量恢复率为基质沥青、SBS改性沥青热再生混合料的2.9~3.1倍、1.9~2.2倍.