Evaluation of In Situ Pavement Layers with the Dynamic Cone Penetrometer (DCP)

The dynamic cone penetrometer (DCP) is rapidly becoming the primary tool for assessing the in situ strength of unbound pavement layers. The U.S. Army Corps of Engineers (USACE) has adopted the DCP for use in the evaluation of existing unbound pavements and shallow foundations. This paper describes the USACE's recommended procedures for using the DCP to evaluate in situ pavement materials. Regression models are presented to describe the relationship between the penetration rate or DCP index and the California Bearing Ratio (CBR), as well as a method for converting DCP results into bearing capacity values. Analysis techniques for interpreting DCP results are presented, and limitations of the device are noted. The results of the analyses show that the correlations provide a simple means of obtaining estimates of key material properties. The relationships between penetration rate and CBR appear to be valid with some scatter associated with inherent variability of natural materials. The techniques and relationships described in this paper provide a relatively reliable means of estimating in situ material properties with the DCP. For the covering abstract see ITRD E139491.