Material Characterization and Seasonal Variation in Material Properties

The main objective of this study was to calibrate the AASHTO temperature and seasonal adjustment models, or to develop new models. The models developed are based on New Jersey conditions and will be also used in network and project level FWD analysis. To achieve the objective of study, twenty-four pavement sections were instrumented and nondestructive testing (NDT) program was conducted for a period of two years. The main task of the instrumentation was to monitor environmental parameters: air and pavement temperature, moisture, frost/thaw depth and rainfall. Seismic Pavement Analyzer (SPA) and Falling Weight Deflectometer (FWD) were used to evaluate the pavement structural response and it's properties on a monthly basis, except during the spring thaw period when it is on a bi-monthly basis. The models were developed by performing statistical analyses, such as analysis of variance (ANOVA) and regression analysis. Several important conclusions were developed with respect to the applicability of the Enhanced Climatic Model (EICM) to New Jersey conditions. Results of NDT evaluations provided strong correlations between all environmental parameters, except the ground water level and the overall pavement deflection, difference in pavement deflections and the effective pavement modulus obtained from FWD evaluation. Seismic tests provided a strong correlation between the AC modulus and pavement temperature. It is recommended that for the FWD data corrections using the temperature adjustment model be followed by the seasonal adjustment model. A number of other conclusions and recommendations related to measurement and relationships of environmental variables and material characteristics and effects of drainage conditions are provided.