Relation of HP‐GPC Profile with Mechanical Properties of AC Mixtures

This paper presents an experimental analysis of the relationship between the relative quantity of a particular‐size molecule in asphalt cement and the mechanical properties of asphalt concrete. Three AC‐20 grade asphalt cements (AC) and recovered asphalt cements from four sources were used for high pressure‐gel permeation chromatography (HP‐GPC) testing and for preparing asphalt‐concrete mixtures. Specimens of laboratory‐prepared asphalt concrete and field cores were tested for tensile strength and resilient modulus in dry and wet conditions. Multiple‐regression analyses indicate that tensile strength and resilient modulus had significant correlations with certain areas of chromatograms that are divided into 10 slices. Tensile strength appears to be sensitive to variation of the relative areas of the second and third slices $(T_2+T_3)$ and resilient modulus vary with the area of the first, second, and third slices $(T_1+T_2+T_3)$. In general, higher relative quantity of larger size molecules cause lower tensile strength and resilient modulus. However, there was no threshold value of the relative quantity of large molecules that showed a peak value for a mechanical property.