TPU/Nano-ZnO复合改性沥青的性能研究及微观机制

Study on Performance and Micro-mechanism of TPU/Nano-ZnO Composite Modified Asphalt

为促进聚合物/纳米改性沥青在耐久性路面中的应用,在实验室将不同掺量的聚氨酯及纳米氧化锌添加到A-70#基质沥青中制备了复合改性沥青。采用传统物理性能试验、动态剪切流变试验(DSR)、弯曲梁流变试验(BBR)研究了其物理性能与流变特性,基于响应面法的优化设计来明确两种改性剂的最佳掺量。借助傅里叶红外光谱试验(FTIR)对其微观改性机理进行探讨。采用高压紫外汞灯环境箱对改性沥青进行不同时间的紫外老化,分析其抗紫外老化能力,并基于主成分分析法评价了老化性能测试指标的显著性。结果表明:聚氨酯与纳米氧化锌的共同作用提高了基质沥青的高温稳定性及低温抗裂性,两种改性剂的最佳掺量分别为5%、3%。根据FTIR结果,复合改性沥青的改性过程既存在物理共混,又有化学加成反应。聚氨酯及纳米氧化锌的加入在基质沥青紫外老化过程中能够抑制羰基、亚砜基等极性基团的生成,复数剪切模量、羰基指数、劲度模量及亚砜基指数对沥青紫外老化性能的影响最为显著。

To promote the application of polymer/nano-modified asphalt in durable pavement,the composite modified asphalt was prepared by adding different dosage of TPU and nano-ZnO to A-70#matrix asphalt in the laboratory.The physical properties and rheological properties were studied by traditional physical properties test,dynamic shear rheological test(DSR)and bending beam rheological test(BBR).The optimal dosage of the two modifiers was determined based on the response surface method.The microscopic modification mechanism was discussed by Fourier infrared spectroscopy(FTIR).The anti-ultraviolet aging ability of the modified asphalt was analyzed by using high-pressure ultraviolet mercury lamp environment box.The significance of the aging performance test index was evaluated based on principal component analysis.The results show that the high temperature stability and low temperature cracking resistance of the matrix asphalt can be improved by the joint action of TPU and nano-ZnO,and the optimal dosage of the two modifiers is 5%and 3%,respectively.According to the results of FTIR,there are both physical blending and chemical addition reaction in the modification process of composite modified asphalt.The addition of TPU and nano-ZnO can inhibit the formation of polar groups such as carbonyl and sulfoxide groups in the ultraviolet aging process of asphalt.The complex shear modulus,carbonyl index,stiffness modulus and sulfoxide index have the most significant influence on the ultraviolet aging properties of asphalt.