Test of surface free energy of asphalt by digital image processing

In Formula (1): θ is contact angle (°); γs is solid surface free energy (mJ/m2); γl is liquid surface free energy (mJ/m2); γ s

d is dispersion component of solid surface free energy (mJ/m2); γ s

p is polar component of solid surface free energy (acid-alkali force) (mJ/m2); γ l

d is dispersion component of liquid surface free energy (mJ/m2); γ l

d is polar component of liquid surface free energy (mJ/m2).