Proposed Approach for Determining Consistent Energy Parameters Based on the Surface Free Energy Theory

The surface free energy (SFE) components obtained from the Good-van Oss-Chaudhury (GvOC) method have been demonstrated to depend strongly on the selected test liquid set. To address this issue, the condition number approach and the equation of state (EQS) approach were proposed previously to select appropriate test liquids. However, little work has been done to verify the consistency of the calculated energy parameters using the various liquid sets. This study was aimed at obtaining consistent energy parameters using different liquid sets designed by five test liquids, which are distilled water (W), formamide (F), glycerol (G), ethylene glycol (E), and diiodomethane (D). A new approach was proposed to make use of the Owens-Wendt (OW) model to calculate the energy parameters with WFED and WFGED considered as the optimum liquid sets. The calculation results indicate that the calculated energy parameters are consistent when using the optimum liquid sets and the rankings of energy ratios are consistent with the boiling water test results for different asphalt mixtures, which fully validates the feasibility of the proposed approach.