Pavement Modulus Determination by Light Weight Deflectometer with Optional Radial Geophones

Abstract

The elastic modulus is an important parameter for the design and quality control of pavement structures. In the past, the elastic modulus was determined from cored samples from the fields. Damage to pavement structures may be avoided by using nondestructive tests such as the Light Weight Deflectometer (LWD) which recently gained more attention. A basic LWD apparatus consists of one load cell and one accelerometer, but its performance can be enhanced by adding more sensors in the radial direction from the center of the load plate. The additional sensors are useful because more constraint conditions can be introduced during inversion process, especially when involving non-homogeneous pavement structures. In this study, an LWD equipped with two additional sensors, the Microtremor method and the Dynamic Probing Light (DPL) are used to determine the modulus of pavement structures. The LWD predictions agree well with the Microtremor results while more scattered relationships are observed when comparing with the Dynamic Probing Light (DPL) results. Nonetheless, the study results demonstrate that the LWD with radial sensors is a viable option for the quality control of pavement construction in Thailand.