Use of Instrumented Dynamic Cone Penetrometer in Pavement Characterization

The dynamic cone penetrometer data had been conventionally used for estimating the base and subgrade California bearing ratio. In recent years, a need for developing mechanistic pavement design procedures has been emphasized. However to develop mechanistic pavement design procedures, measuring engineering properties of pavement layers is essential. Two modifications to the existing dynamic cone penetrometer have been proposed in this paper for obtaining engineering properties of pavement layers. First, an ordinary dynamic cone penetrometer was instrumented with a load cell and an accelerometer to determine the energy imparted to the ground, the resistance to the penetration, and the penetration of the device into the base and subgrade. A second device consisting of a three-dimensional accelerometer embedded in a DCP-like rod was developed to measure modulus and Poisson's ratio of the base and subgrade layers. This device can be placed in the same hole drilled for the first device, thus, requiring minimum coring. Although both devices are proven to be feasible, further analysis is needed for reliably extracting information from these measurements.