Comprehensive physico-chemical and rheo-mechanical characterization of multiple asphalt binder microphases to meet Egyptian conditions

Abstract

Egypt, nowadays, has obvious complementary advantages in the infrastructure construction sector especially in the fields of highways and airports, resulting in drawing attention to utilizing polymer-modified asphalt (PMA). The main aim of this study is investigating physical, chemical, mechanical, and rheological characteristics of five asphalt binder microphases at different aging conditions to nominate which one best suit the Egyptian climatic conditions through a comprehensive experimental testing matrix. The five examined binder microphases are: base asphalt (BA), recovered asphalt (RA), crumb rubber-modified asphalt (CRMA), CRMA with RA (CRRA), and styrene–butadiene styrene-modified asphalt (SBSMA) which are locally available. First, qualitative, and quantitative analytical tests are used to study the physical and microstructural properties of each microphase component of the tested asphalt binders. Additionally, the mechanical and rheological properties of the investigated asphalt binder microphases at original, short-term aged, and long-term aged conditions are examined at different temperature levels. Overall, the testing results show physico-chemical interactions between the BA and the used polymers during mixing and aging processes. The CR and SBS play a significant role in delaying the decomposition process, improving thermal stability, softening point, and Superpave performance grade as well as enhancing rutting, fatigue, low thermal resistance, aging sensitivity, and temperature susceptibility. Carbonyl, Sulfoxide, and Phase angle aging indices are significantly correlated and are rationally able to characterize the aging behavior of the investigated binder microphases. Finally, CRMA, CRRA, and SBSMA proved their performance suitability among the investigated microphases to match the Egyptian climatic conditions.