Moisture Effects of DCP and PFWD Measurements - Phase I

Project summary:

Mechanistic-empirical design, quality assurances, and quality control testing require the stiffness and strength properties of subgrade soils to be measured reliably. It is well known that both stiffness and strength are greatly affected by the soil moisture and stress state. There is currently no reliable method to measure the in-situ stiffness, strength, and moisture during construction and then relate these to the seasonal values used during the design process.

To bridge this gap, this project is focused on laboratory development that provides the means for evaluating the effects of moisture on the soil?s resilient modulus. This is an initial phase of a larger project aimed at understanding and quantifying the effects of moisture on portable weight deflectometer and dynamic cone penetrometer measurements. The key benefit of this investigation will be the development of a reliable laboratory setup and procedure for testing partially saturated soil specimens, without which the PFWD and DCP estimates of soil stiffness obtained from either field or reduced-scale testing cannot be verified.