Characterization of surface free energy of mineral filler by spreading pressure approach

•Propose a spreading pressure approach based on a generalized Washburn equation.•Measure spreading pressure of reference liquid on mineral filler through vapor adsorption test.•Determine specific surface area of mineral filler based on the modified BET model.•Compute resultant effective capillary radius and spreading pressure of mineral filler based on capillary rise test results.•Validate the proposed approach through a standard asphalt mastic moisture susceptibility test.