Effects of Adding a Geotextile into a Pavement Structure on FWD Experimental Data and Estimated Pavement Remaining Service Life

Impregnated geotextiles are commonly used in road construction or rehabilitation to minimize water infiltration into the pavement structure. However, the effects of such waterproofing membranes on the mechanical behavior of the pavement structure are difficult to predict. In this paper, Falling Weight Deflectometer (FWD) measurements were used to highlight differences between pavement structures with and without geotextile. The FWD measurements were performed on two recently rehabilitated roadways where a bitumen impregnated non-woven geotextile was placed between the surface layer and the base layer for some sections. The FWD measurements were performed on both sections rehabilitated with and without the geotextile and the deflection basins were compared. The surface curvature index (SCI), the base damage index (BDI) and the base curvature index (BCI) were also compared. The measurements were then used to predict the remaining service life (RSL) of the pavement structures. The results of this study suggest that traditional approaches used to interpret FWD measurements are not suitable when a bitumen impregnated geotextile is present between two asphalt layers.