Structural Response of LVR Flexible Pavements at Mn/Road Project

Abstract

Pavement surface deflection basins provide valuable information for the structural evaluation of flexible pavements. Surface deflection measurements are rapid, inexpensive, and nondestructive and are used frequently as an indicator of pavement structural capability and performance potential. In this study, falling weight deflectometer testing results on the conventional flexible pavements (asphalt concrete surface, granular base/subbase) and aggregate-surface/surface-treated test sections in the low-volume road loop at the Minnesota Road Research Project (Mn/ROAD) were analyzed to evaluate the effect of granular material quality on the pavement structural response. Asphalt concrete (AC) modulus and subgrade ``break-point`` modulus were back-calculated using algorithms previously developed at the University of Illinois. The surface deflections were normalized to the same AC modulus and subgrade modulus. The analyses show a limited effect of granular material quality on the pavement deflection response in the case of conventional flexible pavements. Because of higher granular layer stresses, the granular material quality effects on the pavement surface deflection response of surface-treated/aggregate-surface pavements are significant. Increased AC thickness reduces the effect of granular base quality on the pavement deflection response.