DIPLODEF - A unified backcalculation system for asphalt and concrete pavements

The absence of a single backcalculation program that can incorporate all combinations of the four widely used pavement models (elastic layer, plate, elastic solid, and dense liquid) deprives the pavement community of the ability to perform comparative studies. The program DIPLODEF was developed to analyze both asphalt concrete and portland cement concrete pavement systems. The new code was assembled from an existing backcalculation program called WESDEF by replacement of its engine, WESLEA, with DIPLOMAT. In addition to the elastic layer and elastic solid models, DIPLOMAT can accommodate the plate and dense liquid idealizations and can analyze multilayer asphalt and concrete pavement systems with user-defined inputs. DIPLODEF has been thoroughly debugged and tested for consistency and reasonableness. Analyses involving various combinations of elastic layers, plates, and springs were performed. Finally, a rating scheme was devised to standardize the assessment of the precision of backcalculated values and permit consistency in comparisons of results.