Asphalt mixture performance deterioration in the salty environment based on theoretical calculation

Abstract

In a salty environment, the asphalt mixture is exposed to the effect of sodium chloride which can affect its performance. Using less energy and raw materials, a model was effectively created in this study to predict the influence of sodium chloride on the performance of the asphalt mixture (rutting resistance and fatigue damage) in a salty environment. To ascertain the physical characteristics of the asphalt binder at various salt solution proportions, fundamental tests such as the penetration test, softening point, and ductility test were performed. Additionally, the Dynamic Shear Rheometer (DSR) was used to conduct the temperature sweep test in order to assess the rheological characteristics of asphalt binder samples before and after immersion in different salt solutions. Based on the DSR results and mixture volumetric parameters, the Hirsch model and the Asphalt Institute (ALI) model were used to forecast the performance of the asphalt mixture. The test results indicated that the asphalt mixture with the highest complex modulus (G*), lowest voids in mineral aggregate (VMA), and highest voids filled with asphalt binder (VFA) had the highest value of dynamic modulus, which is preferable to increase the asphalt mixture's resistance to rutting. The maximum rate of deterioration was estimated to be 45% at 15% salt content, followed by that of 10% salt content (26.76%), and 5% salt content (22.8%). However, the findings from the ALI model revealed that the fatigue life of the asphalt mixture in the presence of salt solution significantly decreased when compared to the specimen soaked in plain water, indicating that salt was detrimental to the mixture's resistance to fatigue cracking. The largest rate of deterioration was 37.11% at 15% salt content, and it was followed by rates of 22.35% at 10% salt content and 19.13% at 5% salt content.