Construction of New Penetration Grading for Asphalt Binders

Major critics of the present penetration grading often point to the empirical method and the absence of temperature dependency. To resolve these critics, a better penetration grading is suggested at the first time in this study. This grading is proposed on the basis of the new theory, that is developed by applying the relationship between pavement rut depth and binder penetration, the relationship between penetration and test variables(temperature, weight, etc.), and the time-temperature superposition principle. Since this theory requires a reference binder, it is determined as the one which passes the rut-stability criterion in the wheel tracking experiment. The selection of reference binder and the new grading theory allow one to grade all domestically used binders and to analyse how the new grading is different from the present one. A substantial difference between the two is found as the result of such analysis.