Falling Weight Deflectometer vs Laboratory Determined Resilient Modulus (Slab Curling Study)

Stantec Consulting completed Falling Weight Deflectometer (FWD) testing on three portland cement concrete (PCC) slabs built at East Brunswick location. Two sets of FWD testing were performed, one on August 5, 2005 and the second on October 28, 2005. Dynatest Model 8002-231 series FWD was used for deflection testing. Deflection tests were performed on three constructed slabs along three paths (right wheel path, edge and slab center line) using three load levels, 9000, 12000 and 14000 lbs. The pavement deflections measured with the FWD were used to determine the structural properties of the pavement layer and subgrade soil through the backcalculation. The backcalculation analysis was performed according to 1993 American Association of State Highway and Transportation Officials (AASHTO) Design Guide to calculate the in-situ pavement structural capacity and subgrade modulus. The pavement PCC thickness varied slightly from 11 in. to 11.5 in.; therefore a thickness of 11.5 in. was used in the backcalculation analysis. A 4 in. base and 4 in. subbase thickness were assumed for the backcalculation analysis.