Use of DCP (Dynamic Cone Penetrometer) and LWD (Light Weight Deflectometer) for QC/QA on Subgrade and Aggregate Base

The DCP (Dynamic Cone Penetrometer) and LWD (Light Weight Deflectometer) are becoming ever more popular as mechanistic-empirical pavement design/construct procedures evolve. These instruments provide the ability to quickly, accurately, and economically measure shear strength and stiffness of in-place base course and subgrade material, thus obviating the need for density testing. These instruments are rugged, portable, easy to operate and do not have the regulatory disadvantages of a Nuclear Density Gauge. This paper outlines the genesis of the DCP for soil testing and the respective applications for various DCP configurations. The various types of LWDs and the results they produce are described. Finally, on going efforts in the use of these instruments as well as standards for QC/QA (Quality Control /Quality Assurance) for subgrade and aggregate base for roads are discussed.