Evaluation of asphalt binder properties in surface treated pavements

Application of surface treatments are based on predetermined treatment schedules and empirical observations of the surface condition with time. This paper investigates the change in properties of asphalt binders extracted from treated pavement sections to identify an optimum application time. Dynamic Shear Rheometer (DSR), Direct Tension Test (DTT) and Bending Beam Rheometer (BBR) tests were performed on extracted binders. Ten sections, two control and eight surface treated sections representing treatments applied at pavement ages from 1 to 8 years, were sampled from Trunk Highway 56 in MN, USA. Statistical analysis of the BBR data suggested that age before treatment is significant for creep stiffness but not for m-value. Significant differences were observed in m-values with respect to depth and location. No significant correlations were observed between the age before application of treatment and the DTT fracture parameters. Contrary to what it was expected, there is a significant negative corre-lation between age of pavement and |G∗| due to the fact that the emulsion application rate in-creased with the age of the pavement. The analysis indicates that construction practice has a ma-jor influence.