Correlation study with the light weight deflectometer in South Africa

Abstract

The Light Falling Weight Deflectometer (LWD) has recently become available in South Africa as a portable, light weight, user friendly version of the well established Falling Weight Deflectometer (FWD). This device uses very similar technology to the FWD device to most closely simulate the loading rate and area of a single moving wheel. However, with its reduced maximum applied force and load pulse duration, the LWD has a shallower depth of influence than that of the FWD. It is, therefore, ideal for single layer structural evaluation during construction to provide better engineering parameters for quality assurance and quality control. (QA/QC) of constructed granular layers and lightly cemented layers than merely conventional density measurements only. Various correlations with other non-destructive structural evaluation devices have been done elsewhere in the world indicating the potential of the LWD as a tool to assist in decision-making related to structural integrity of individual road pavement layers for a wide range of materials. Limited correlation studies between the FWD and LWD in SA have also confirmed this observation. This paper presents findings from a study on correlation between the LWD and FWD test results for sand treated with emulsion (STE) on an experimental construction site in Mozambique