Resilient modulus estimation using in-situ modulus detector: performance and factors

The resilient modulus of subgrade should be estimated for pavement designs that undergo repetitive loading from vehicular movement. In this study, an in-situ modulus detector (IMD) with flat, wedge, and cone tips is employed to estimate the resilient modulus. The specimens with three different levels of water content are compacted, and the dynamic responses for two hammer drop heights are analysed. For all specimens, elastic waves are acquired to estimate the shear modulus and Poisson’s ratio using bender and piezo-disk elements. The resilient modulus estimated from the IMD is compared with the lightweight deflectometer (LWD) modulus. The experimental results show a stronger relationship between the flat and wedge tips than between the cone and wedge tips. Furthermore, higher drop heights result in strong relationships between the resilient, shear, and LWD moduli. This study proposes an intrinsic design and verification of an IMD for reliable resilient modulus estimation in pavement design.