根据表面能理论,采用接触角测量法测定盐冻循环前后苯乙烯-丁二烯-苯乙烯(SBS)、废胎胶粉(CR)和复合胶粉(CCR)3种聚合物改性沥青、石灰岩、玄武岩和花岗岩的表面自由能参数,分别计算出盐冻循环前后沥青-矿料系统的粘附功和剥落功,从而确定盐冻循环对沥青-矿料系统粘附和剥落特性的影响。结果表明:盐冻循环前后,沥青与矿料的粘附过程以及水侵入沥青-矿料界面的剥落过程的比表面自由能变化均为负值,说明沥青与矿料的粘附过程和剥落过程均自发进行;随着盐冻循环次数和盐浓度的增加,沥青-矿料系统粘附功逐渐减小,剥落功逐渐增大,粘附性和抗水损害能力逐渐减弱;当沥青种类相同时,沥青与石灰岩的粘附功最大,剥落功最小,沥青与花岗岩的粘附功最小,剥落功最大;当矿料种类相同时,CCR改性沥青与矿料的粘附功最大,剥落功最小,SBS改性沥青与矿料的粘附功最小,剥落功最大。
According to the theory of surface energy,the surface free energy parameters of styrene-butadiene-styrene(SBS),crumb rubber(CR)and composite crumb rubber(CCR)of three kinds of polymer modified asphalt before and after salt freezing cycle and limestone,basalt,granite were measured by contact angle measurement method.Adhesion work and spalling work of asphalt-aggregate system were calculated before and after salt freezing cycle,so as to determine the influence of salt freezing cycle on the adhesion and spalling properties of asphalt-aggregate system.The results show that the specific surface free energy variation of adhesion process and spalling process of asphalt and aggregate system are all negative before and after salt freezing cycle,explaining the process of adhesion and spalling of asphalt and aggregate are all spontaneous.With the increase of salt freezing cycles and salt concentration,the adhesion work of asphalt-aggregate system gradually decreases,and the spalling work gradually increases,adhesion and resistance to water damage ability are weakened gradually.When the asphalt type is the same,the adhesive work of asphalt and limestone is the largest,and the spalling work is the smallest,the adhesive work of the asphalt and granite is the smallest,and the spalling work is the largest.When the aggregate type is the same,the adhesive work of CCR modified asphalt and limestone is the largest,and the spalling work is the smallest,the adhesive work of the SBS modified asphalt and granite is the smallest,and the spalling work is the largest.