The paper reports results from a research programme assessing pavement response to heavy vehicles. The Technical University of Denmark and The Danish Road Institute cooperated in the research programme. To estimate the validity of theoretical values of stress and strain in pavements, stress and strain distributions were measured under two types of loads: (1) was rolling truck tires simulated by the Road Testing Machine, and (2) was Falling Weight Deflectometer (FWD) loadings. Distributions of stress an( strain are explored and mapped in three-dimensional graphs. The researchers attempted to compare some measured response distributions to calculated distributions. The measured responses are (a) vertical contact stress in the tire/pavement interface; (b) longitudinal and transversal asphalt strain; (c) vertical soil stress; and (d) vertical soil strain. As temperatures and layer thicknesses in the Road Testing Machine are well known, only Poisson's ratio is estimated for the calculations. The E-value of each layer was back-calculated from FWD load and deflections. Using elastic layer theory with back-calculated E-values and the chosen values of Poisson's ratio, values of stress and strain are calculated at the positions of the instruments. FWD load response values are considered the means for in-situ calibration of stress cells.
Abstract