Nebraska LTAP


Date of this Version


Document Type



Barrett, B., Troxel, K., and Dresselhaus, B. (2021). Measuring Foundation Course Modulus Using Falling Weight Deflectometer, Light Weight Deflectometer, and Dynamic Cone Penetration. NDOT Research Report.


The purpose of this investigation was to determine the feasibility of measuring bituminous foundation course modulus under concrete roadways by comparing testing results derived before and after paving using FWD, Light Weight Deflectometer (LWD), and Dynamic Cone Penetrometer (DCP). The foundation course modulus was determined using FWD data and Darwin design software (‘93 AASHTO). Results from Phase I data collection, which occurred prior to pavement placement, provided a baseline for comparison. The maximum modulus was 398,000 PSI and the minimum was 85,000 PSI, yielding a range of 315,000 PSI and an average modulus of 123,000 PSI over the length of the test plot.