SEDL / STP / STP1198-EB / STP18148S

Comparing Laboratory and Backcalculated Layer Moduli on Instrumented Pavement Sections

Akram, T
Graduate Research Assistant, Texas Transportation Institute, Texas A&M University, College Station, Texas

Scullion, T
Assistant Research Engineer, Texas Transportation Institute, Texas A&M University, College Station, Texas

Smith, RE
Associate Research Engineer, Texas Transportation Institute, Texas A&M University, College Station, Texas

Pages: 33    Published: Jan 1994

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Abstract

This paper discusses the analysis of deflection data on thick and thin asphaltic concrete pavement sections instrumented with Multidepth Deflectometers (HDD's). Surface and depth deflection data were collected under both Falling Weight Deflectometer (FWD) and truck loadings. Linear elastic analyses were performed to compare layer moduli backcalculation from; • FWD surface deflections only; and • FWD surface and depth deflections only.

Backcalculated moduli values were compared with those measured in the laboratory. The moduli calculated from FWD loads were also used to predict pavement response under known truck loads. These predictions were compared to actual measured responses. In general it was found that the FWD characterization overestimates the strength of the subgrades and underpredicts subgrade strains induced by the truck by 18%.