Dynamic cone penetrometer user's guide
Abstract
The Dynamic Cone Penetrometer (DCP) is a rapid and inexpensive device for characterizing
unbound paving materials and subgrade soils. The DCP may be used to estimate the strength of
these materials through the use of correlations with the California Bearing Ratio (CBR) and
resilient modulus (Mr).
The DCP, shown schematically in figure 1, consists of the following components: a 15.8-mm
(5/8-in) diameter steel drive rod with a replaceable cone tip, an 8-kg (17.6-lb) weight or hammer
which is dropped a fixed height of 575 mm (22.6 in), a coupler assembly, and a handle. The cone
tip has an included angle of 60 degrees and a diameter at the base of the cone of 20 mm (0.79 in).
The drive rod may be unmarked or graduated so that increments of 5.0 mm (0.2 in) may be
determined. The apparatus is typically constructed of stainless steel, with the exception of the
cone tip, which may be constructed from hardened tool steel or a similar material.