Analysis on Splitting Strength of Warm Mix Asphalt Based on Theory of Surface Free Energy

In this paper, splitting strength and freeze-thaw splitting strength of warm mix asphalt (WMA) are analyzed based on material surface free energy (SFE). Firstly, SFE, polar component and dispersion component of asphalt with different additives (Sasobit®, anti-stripping agent) are measured through sessile drop method; Secondly, SFE and specific surface area (SSA) of limestone and granite are measured separately by capillary rise method and BET adsorption method; Fatherly, work of adhesion between asphalts and aggregates is calculated; At last, the author analyzes the relationships between SFE, each component, work of adhesion and splitting strength, freeze-thaw splitting strength of mixtures. The results show that: polar component of asphalt and splitting strength is negatively correlated, but dispersion component is positively correlated; and Sasobit® makes dispersion component of asphalt reduce, but polar component increase, so splitting strength, freeze-thaw splitting strength of mixtures with Sasobit® reduce legitimately; work of adhesion between asphalt and granite is larger than limestone, but the SSA of limestone is 1.4 times than granite, therefore, splitting strength, freeze-thaw splitting strength of mixtures with limestone are larger than granite; with the dosage of Sasobit® increases, the work of adhesion, splitting strength and freeze-thaw splitting strength of mixtures are changed similarly.