Research on Asphalt Pavement FWD Deflection Synthetic Correction Coefficient

Abstract

Deflection was adopted as control criteria in asphalt pavement construction quality management in China. Static parameters and Burmister layered system were used to calculate deflection in existing design procedure, but the difference between the deflections calculated from this way and deflections measured from FWD could reach 50%. This study introduced a deflection synthetic correction coefficient, F, to shorten the difference gap. Through Deflections collected from indoor and in-field full scale test sections combined with test roads in six freeways, meanwhile, ABAQUS was used to create three dimension finite element module to simulate the response of test sections and calculate their deflections under moving vehicle loads, then comparison was conducted between deflections measured by FWD and deflections calculated from ABAQUS. Finally, the grey entropy theory was utilized to determine the influence factors which are prepared for constructing the formula of F. The study concluded that the difference between calculated deflection after correction and deflection measured in field decreased to 30%, which enhanced the precision of management of construction quality through surface deflection, and an encouraging way to judge the reasonability of deflection measured by FWD.