ABSTRACT
In order to study the adhesion properties of fast-melting SBS-modified asphalt (SBS-T) at the interface with aggregates, the contact angles of three dosages of SBS-T asphalt with three liquids (distilled water, glycerol, and formamide) were determined by the sessile drop method based on surface free energy theory. The evaluation indexes such as cohesion, asphalt-aggregate adhesion, stripping work and energy ratio of the asphalt were analyzed and the adhesion properties of the asphalt-aggregate system were investigated with the help of micromechanical methods. The results indicate that SBS-T can improve the adhesion properties of the asphalt. Furthermore, as the dosage of the modifier increases, the cohesion work, adhesion work, and energy ratio of the SBS-T asphalt exhibit a similar rise. As the spalling work reduces and the adhesion between asphalt and aggregate improves, it is noteworthy that the SBS-T asphalt-aggregate system exhibits superior adhesion performance compared to the SBS-modified asphalt-aggregate system, despite the same dosage.
ABSTRACT
This study was designed to establish the method of characterization of surface free energy(SFE)and evaluate the compaction properties of pharmaceutical materials based on SFE. We investigated the contact angles of materials with water and diiodomethane under different compression pressures. The contact angles of materials at 353 MPa compression pressure were utilized to calculate the related parameters of SFE ultimately. The area under tensile strength-compression pressure curve(AUTSC)and pressure yield(Py)were employed to evaluate the compactibility of material. Additionally, Pearson correlation analysis was utilized to analyze the relationship between the SFE and the compaction properties of pharmaceutical materials. The results exhibited that SFE had a significant correlation with the compaction properties of materials(P < 0.05). Moreover, the related parameters of SFE, i.e., cohesive work(Wco)and polarity index(PI)of SFE, were positively correlated with Py of Heckel equation and negatively related with AUTSC. The higher values of Wco and PI, the stronger repulsive force among the particles, led to a worse compaction behavior. In this study, we established the method for characterization of the compaction behavior of materials based on SFE initially. This study also demonstrated that SFE could evaluate the compaction behavior effectively, which provides a better understanding of compaction behavior for pharmaceutical researchers.
