基于表面能理论的除冰盐侵蚀沥青矿料界面机理研究

Study on erosion of new de-icing salt on asphalt mixture based on surface energy theory

冬季沥青路面除冰雪养护工作中,醋酸类新型除冰盐的使用已对沥青路面造成侵蚀破坏,本文依据表面能理论研究分析新型除冰盐对沥青混合料的侵蚀破坏机理.研究首先利用Van Oss三相物质界面接触过程中的自由能变化理论,构建溶液侵蚀沥青-矿料界面动力学模型;基于Young-Dupré液体在固体表面接触角理论,利用滴落法和毛细管上升法求解出沥青、石灰石矿料的表面能参数;并利用逆向求解的方法得到不同浓度除冰盐溶液的表面能参数;计算得出除冰盐侵蚀破坏过程的三相系统(沥青、矿料和除冰盐溶液)的吉布斯自由能变化,从而基于表面能理论以及分子官能团组成角度进行了深入的机理解释.结果表明:醋酸类除冰盐溶液对沥青-矿料的界面侵蚀破坏的能力较蒸馏水强,且侵蚀趋势随溶液浓度增加而增加,反应过程自发性逐渐增强;侵蚀破坏主要与醋酸类除冰盐中醋酸根双亲(亲水亲油)的乳化特性以及沥青-矿料界面处的缺陷有关.

During the winter maintenance work,the use of new de-icing salt makes erosion damage of asphalt pavement.The contact angles of de-icing salt solution on asphalt surface as well as mineral aggregate surface were determined by Sessile Drop and Capillary rise,respectively.This study calculates the composition of surface energy of asphalt,mineral aggregate and sodium acetate solution,and analyses,using the surface energy theory as well as Gibbs free energy relationship,the stability of asphalt mixture in different composition systems and the erosion tendency of de-icing salt solution on mineral aggregate-asphalt interface.The results show that the erosion of de-icing salt solution on limestone-asphalt interface is more obvious than water.Moreover,the erosion tendency increases with increasing solution concentration and the process has a strong spontaneity.The erosion damage depends on the amphiphilic structure of acetate ion and defects of asphalt-aggregate interface.