基于表面能理论分析pH值对沥青混合料粘附性的影响

Evaluating the Influence of pH Value on Adhesive Property of Asphalt Mixture Based on Surface Energy Theory

为探究水溶液的pH值对沥青-集料粘附性的影响,以5种不同酸碱性的水溶液为试验样品,采用铂金板法分别测试在20℃时的表面能值,并基于表面能理论分别计算70#沥青-辉绿岩-水溶液和70#沥青-石灰岩-水溶液的三相体系粘附功,同时比较这2种组合的水稳定性指标ER随水溶液pH值的变化情况.结果表明,随着水溶液pH值的增大,沥青混合料三相粘附功的绝对值会减小,ER指标会增大,说明沥青混合料的粘附性和水稳定性随着水溶液pH值的增大会变得越来越好.使用水煮法对表面能计算结果进行验证,发现沥青膜的剥落面积随水溶液pH值的增大而减小,这与ER指标表征的规律相同.

In order to investigate the influence of water＇s pH value on asphalt-aggregate, 5 different acidic liquids are prepared as the test samples and the platinum plate is used to measure their surface energies. Then the adhesive work based on the surface energy theory is calculated for 70 asphalt binder-diabase-liquid and 70# asphalt binder-limestone-liquid,respectively. At the same time,the ER index which can be used for evaluating asphalt mixture＇s water stability is analyzed for each combination. The results show that the absolute value of asphalt mixture＇s adhesive work will decrease and the ER index will increase with the increase of liquid＇s pH value, which indicates that the adhesive property and water stability of asphalt mixture will become better with the increase of liquid？s pH value. The water-boiling test has been employed to validate the results as well and it shows that the stripped asphalt film will decrease with the increase of liquid？s pH value？ which leads to the same conclusion as ER index.