ABSTRACT
The purpose of this study was to contribute to the development of portable measurement devices for characterization and compaction control of unbound pavement layers. The paper presented a proof-of-concept study utilizing a prototype flexible strain sensing plate and a straightforward data interpretation scheme to determine subgrade elastic modulus utilizing recent advances in fiber-optic technology. The approach involved tracking the location of distinct points of zero and minimum strain along fiber-optic cables glued to the flexible plate and relating their shift in location to the changes in the subgrade elastic modulus. For initial validation, the methodology was successfully demonstrated on a simple laboratory-scale setup, utilizing a Plexiglas plate and Polystyrene block to represent the plate and support material, respectively. It was shown that the approach proposed is direct, load-independent, and allows for accurate determination of the elastic modulus, assuming that the plate characteristics are known.
