基于厂拌热再生的复合改性橡胶沥青应力吸收层抗裂性能研究

Study on Crack Resistance of Stress Absorbing Layer of Compound Modified Rubber Asphalt Based on Plant-mixing Hot Recycling Technology

为改善路面结构抗反射裂缝能力,提升沥青路面材料循环利用率,将复合改性橡胶沥青与路面循环利用技术综合运用于应力吸收层中,设计制备了复合改性橡胶沥青再生混合料AC-10。通过沥青胶结料试验研究比较了复合改性橡胶沥青、SBS改性沥青、AH-70道路石油沥青及胶粉改性沥青的各项物理指标。基于动态剪切、弯曲梁流变试验分析对比了复合改性橡胶沥青的温度敏感性、低温性能及疲劳性能。应用小梁弯曲、环形加载及含预切缝的半圆弯曲试验方法探究了旧料掺量对复合改性橡胶沥青再生混合料抗裂性能的影响。结果表明:复合改性橡胶沥青的施工和易性比传统胶粉改性沥青更优,且具有温度敏感性低、低温及疲劳性能强的特点,在应力吸收层混合料中具有良好的适用性;复合改性橡胶沥青应力吸收层再生混合料具有良好的抗裂性能,随着混合料旧料掺量的增加呈现强度提高、模量增大、韧性降低及抗裂性能下降的总体规律;综合考虑再生混合料的断裂韧度及断裂能指标,为保证复合改性橡胶沥青再生料在应力吸收层发挥良好的抗反射裂缝效果,旧料掺量宜控制在35%以内;将厂拌热再生技术应用于复合改性橡胶沥青应力吸收层中,兼顾了路面养护的经济效益与环境效益,具有良好的推广意义。

In order to improve the crack resistance of pavement structure and improve the recycling utilization ratio of asphalt pavement material,the compound modified rubber asphalt and pavement recycling technology are applied to stress absorbing layer,and the compound modified rubber asphalt recycled mixture AC-10 is designed and prepared.Through experimental study on asphalt binder,the physical indicators of compound modified rubber asphalt,SBS modified asphalt,AH-70 road petroleum asphalt and crumb rubber modified asphalt are compared.The temperature sensitivity,low temperature and fatigue performance of compound modified rubber asphalt are analyzed and compared based on dynamic shear test and bending beam rheological test.The influence of recycled asphalt pavement(RAP)content on the crack resistance of compound modified rubber asphalt recycled mixture is investigated by beam bending test,annulus loading test and notched semi-circle bending test.The result shows that(1)the workability of compound modified rubber asphalt is better than that of traditional crumb rubber modified asphalt,it has the characteristics of low temperature sensitivity,strong low temperature and fatigue performance,and has good applicability in the stress absorption layer mixture;(2)the compound modified rubber asphalt recycled mixture for stress absorbing layer has good crack resistance,its strength increases,modulus increases,toughness decreases and crack resistance declines with the increase of the RAP content;(3)considering the fracture toughness and fracture energy indicator of recycled mixture,in order to ensure the crack resistance of the compound modified rubber asphalt recycled material in stress absorption layer,the RAP content should be controlled within 35%;(4)the plant-mixing hot recycling technology is applied to the stress absorption layer of compound modified rubber asphalt,which gives consideration to the economic and environmental benefits of pavement maintenance,and has good popularization significance.