This project developed a low cost, mobile, and robust unit of cone penetrometers equipped with piezoelectric sensors that can quickly measure stiffness and Poisson’s ratio of subgrade materials of a pavement under construction or an existing pavement. It offers an automated, accurate, and economical system for monitoring and controlling construction quality and evaluating performance of pavement systems. The concept has been validated in the laboratory and several papers have been published. This project explored the application of the concept to real field situations by improving the design of the device and conducting tests at several pavement project sites. During a test, the cone penetrometers are pushed into the base and subgrade materials and the velocities of P and S waves are measured using piezoelectric sensors, from which the moduli and Poisson’s ratio of soils can be determined. The penetrometers can be pushed into the soil as far as 4 feet deep and the profiles of shear modulus, elastic modulus, and Poisson’s ratio in the soils can be measured in just a few minutes. The test is quick and economical enough that it can be conducted at many locations during construction. The final report is available from the National Technical Information Service (NTIS # PB2007-107339).
The final report for this IDEA project can be found at: