Estimating Structural Parameters Of Cement Concrete Pavements By Using Of FWD

In this dissertation, the methodology for estimating structural parameters of cement concrete pavements by using of FWD (Falling Weight Deflectometer) was studied. As the theoretical basis, two types of subgrade idealizations, the elastic subgrade and the Win]der subgrade, were used. Firstly, the positions and times for implementing the investigation by using of FWD were identified. The approximate formula for calculating the theoretical deflections of the slab-subgrade models was introduced, which was used to estimate the structural parameters of cement concrete pavements. Through an analysis of experimental testing data on four different sites with different pavement structures, the structural parameters, i.e. the elastic moduli of the concrete slab E~, the subgrade reaction parameter k for Winkler subgrade idealization and the elastic moduli of the subgrade for elastic solid subgrade, were estimated. Meanwhile, ranges to arrange the FWD sensor, bias between slab-subgrade theories and actual behaviors of cement concrete pavements under FWD testing were clarified. Finally, for practical application, the calibrating processes by introducing the correction coefficients kPSFWD, kle4lfD and k.,,IF;iD for estimating the loading stress and thermal stress of cement concrete pavements under currently design specification were discussed.