Simple Approach to Estimation of Pavement Structural Capacity

Abstract

The use of the falling weight deflectometer (FWD) as a tool for investigating the structural strength of flexible and rigid pavements is now common. The backcalculation of layer moduli is the primary technique for data interpretation. This technique is cumbersome and expensive to apply to low-volume roads. A simple way of relating the FWD surface deflections to the performance of pavement structures, expressed by the structural number (SN), is presented. The technique is proposed as an alternative to existing methods in Louisiana using Dynaflect data. The relationship was deduced by statistical analysis, using the data collected at the Louisiana Transportation Research Center Pavement Research Facility. The study found that the correlation between the SN and the FWD deflections is satisfactory. Two different relationships are recommended for flexible and semirigid pavements. Both relationships can be applied in a pavement management environment because they allow evaluation of the required thickness for the asphalt overlay. It was found that the structural layer coefficients must be assigned functions of the laboratory moduli determined by the indirect tensile test, not functions of the backcalculated moduli.