ABSTRACT
The durability of flexible pavements in cold regions is a challenge due to the impact of environmental conditions such as extremely low temperatures and freeze-thaw cycling. In an attempt to tackle this issue, several asphalt modifiers have been evaluated as a potential solution to resist degradation and reduction of service life. Among these modifiers, polymer modification has a strong track record in improving the resistance of asphalt mixtures to various distresses typical in cold climates, both loading and environmental driven. The objective of this study is to investigate the structural deterioration of solid, pelletized polymer-modified asphalt pavement sections over the course of one year. Four test sections were constructed in Northern New Hampshire with different polymer dosage rates; control (with no polymer), 2.5% polymer, 5% polymer, and 7.5% polymer by weight of asphalt binder. To assess the structural capacity and performance of the pavement sections, Falling weight deflectometer (FWD) testing was conducted at each test over the course of one year after construction. A comprehensive analysis was performed to scrutinize the measured FWD deflection data for each test section. Backcalculation analysis was conducted to estimate the stiffness of pavement layers and track the asphalt layer’s structural deterioration over time for each pavement section. The field investigation results showed that the modified polymer sections exhibited less degradation over time compared to the control section. In addition, the results suggested that polymer modification to the AC layer results in structural benefits to the pavement structure.
