Abstract
FWD tests are often conducted for evaluating the performance and the bearing capacity of the pavement structures. In heading for the mechanistic-empirical design method at present, it is thought that the importance of the FWD tests will be more greatly enhanced. As for the analysis of the FWD test data, static backcalculation is often utilized considering the peak values of impact load and surface deflections as the static load and corresponding responses. FWD test is an impact load test and a static reverse analysis is done using the corrugated peak value. Because the FWD test is an impact load-test, the peak values of responses differ even if the peak values of loads are same. This study clarifies that the static backcalculation may be accepted when the loading duration is long, but that dynamic backcalculation must be conducted when the loading duration is short. It is found that the dynamic backcalculation is more suitable to evaluate layer moduli of a pavement structure from the FWD test. Moreover, this study proposes the use of layer moduli estimated by dynamic backcalculation when executing rehabilitation design theoretically.
