高掺量胶粉改性沥青及其长寿命路面结构应用研究

High Content Rubber Powder Modified Asphalt and Its Application in Long-life Pavement Structure

为高效利用废旧轮胎胶粉,提升胶粉改性沥青的路用性能,缓解“黑色污染”带来的危害,首先对废旧轮胎胶粉进行活化脱硫处理,然后制备了胶粉掺量为20%~50%的胶粉改性沥青,并开展了基本性能、线黏弹性、蠕变恢复、疲劳损伤特性等性能测试,评价了高掺量胶粉改性沥青的胶浆性能特性。最后,基于“功能-材料-结构”协调设计思想,提出了适合于高掺量胶粉改性沥青的半刚性基层长寿命沥青路面结构和全厚式长寿命沥青路面结构。结果表明,相较于基质沥青,胶粉改性沥青的软化点、PG高温等级、延度等指标均显著提升,高掺量胶粉改性沥青具有更好的低温性能、抗疲劳性能以及热稳定性。胶粉沥青碎石SRA的级配类型,增强了骨架结构内部石料之间的骨架形成和嵌挤能力,确保了包括细集料、矿料及胶粉改性沥青组成胶砂的密实性;设计的30%,40%,50%胶粉掺量的高掺量胶粉沥青混合料的高温、低温、水稳定性等路用性能优良;全厚式长寿命沥青路面结构寿命比原设计路面结构结构大幅度提升,该结构的沥青层疲劳开裂对应的累积当量轴次比原结构的提升了180%,路面可承受的疲劳荷载作用次数达到长寿命路面要求。

To efficiently utilize waste tire rubber powder,improve the road performance of modified asphalt,and alleviate the harm caused by black pollution,the study firstly activated and desulfurized waste tire rubber powder,and then prepared high content rubber modified asphalt with rubber powder content of 20%,30%,40%,and 50%.Basic performance tests,linear viscoelasticity,creep recovery,fatigue damage characteristics,and other rheological performance tests were carried out to evaluate the performance of high dosage rubber modified asphalt.The result indicates that compared with the base asphalt,the softening point,PG high-temperature grade,ductility and other indicators of rubber powder modified asphalt are significantly improved.High content rubber modified asphalt has better low-temperature performance,fatigue resistance,and thermal stability.Then the gradation of rubber powder asphalt crushed stone SRA was proposed,which enhanced the skeleton structure and emphasized the skeleton formation and embedding ability among stones,ensuring the compactness of rubber sand composed of fine aggregates,mineral aggregates,and rubber modified asphalt.Finally,based on the coordinated design concept of function material structure,the semirigid base long-life asphalt pavement structure and the full thickness long-life asphalt pavement structure suitable for high content rubber modified asphalt were proposed.It was found that the high content rubber asphalt mixtures with 30%,40%,and 50%rubber powder content had excellent pavement performance in high temperature,low temperature,water stability,and other pavement performance.The service life of the fully thick long-life asphalt pavement structure was significantly improved compared to the original structure.The cumulative equivalent axis number corresponding to fatigue cracking of the asphalt layer in this structure increased by 180%compared to the original structure.The number of fatigue load actions that the pavement can withstand meets the requirements of long-life pavement.