The main objective of this project was to analyze the response of the different pavement layers to Falling Weight Deflectometer (FWD) loading with special emphasis on the hot-mix asphalt layers. The structural capacity of the 12 flexible pavement test sections was evaluated using a Falling Weight Deflectometer (FWD) as the pavement was constructed. Testing was performed on the surface of each finished layer shortly after the placement of each layer and periodically after that. The deflections obtained from the FWD testing were analyzed to estimate the "as-built" in-situ resilient modulus of each layer. The analysis of the deflection measured over the subgrade was initially used to determine the subgrade modulus and depth to bedrock. The modulus of granular subbase layer (21-B) was then determined based on the deflections measured over that layer. The process was repeated over each subsequent layer to determine the initial moduli for all pavement layers.

A detailed backcalculation analysis was conducted, which includes provisions to combine thin pavement layers, considers the strengthening of the cement treated layer, and criteria to determine the reasonableness of the backcalculated moduli. The measurements over the HMA base layer were repeated at different pavement temperatures to evaluate the temperature susceptibility of the materials. The computed in-situ moduli for the different HMA layers indicated that the initial structural capacity of the mixes is appropriate. The moduli were in reasonable agreement with those expected for these types of materials. Thus, appropriate long-term performance of the mixes can be expected.