Validation of Dynamic Simulation of Slow-Moving Surface Deflection Measurements

Recent studies have concluded that measured surface deflections can be used as a low-cost pavement monitoring and condition assessment tool to determine remaining structural life and pavement performance. Moving load devices are being used more often to measure continuous surface deflections. They are considered a faster alternative to falling weight deflectometer based structural condition evaluation applications. The objective of the study was to compare the analytical dynamic simulation of slow-moving deflection measurements with field data. The surface pavement deflections and the pavement structural responses generated by the Euroconsult Curviametro loading at the Minnesota Department of Transportation's MnROAD facility near Maplewood, Minnesota, were used in the evaluations. Four geophones were embedded near the pavement surface to measure surface deflections during field trials at each of three tested MnROAD cells. In addition, numerous other sensors, such as strain gauges and thermocouple trees, were available at the MnROAD facility. The 3D-Move program was used in the simulations because it can accommodate moving loads and the visco-elastic properties of pavement layers and produce continuous deflection basins. The viscoelastic properties of pavement layers were estimated on the basis of the actual temperatures at the time of the field trials and the appropriate loading frequency of the Curviametro. The proposed dynamic analytical model provided a good match with a variety of independent pavement responses, which included surface deflection basins (measured by embedded geophone sensors) as well as horizontal strains at the bottom of the asphalt concrete layers (measured by MnROAD sensors).