BACKCALCULATION OF MATERIAL PROPERTIES FOR CONCRETE PAVEMENT

Abstract

This paper describes the development of a closed-form backcalculation procedure that yields a unique set of solutions for the layer moduli of a concrete pavement. The procedure is applicable to analyzing concrete pavements consisting of a concrete slab supported on an elastic foundation. For concrete pavement construction that involves a subbase layer, the backcalculation procedure computes the combined effective modulus of the subgrade and the subbase layer. The procedure makes use of surface deflection measurements obtained from falling weight deflectometer tests or any other nondestructive surface deflection measuring equipment. The algorithms use theoretical relationship between surface deflections and applied loads for rigid slabs supported on either a Winkler foundation or an elastic foundation. Numerical integration is performed to compute pavement surface deflections under loads in the forward calculation phase of the backcalculation analysis. Numerical examples are given to illustrate the versatility of the algorithm in backcalculation analysis, such as assessing the reliability of backcalculated layer moduli and detecting erroneous deflection measurements from faulty sensors.