Determination of CBR for fine-grained soils using a dynamic lightweight cone penetrometer

Abstract

Determination of California bearing ratio (CBR) values indirectly from a relationship with the dynamic cone penetrometer (DCP) can offer a valuable alternative approach due to its simplicity and the ability to provide rapid results. The literature review reveals that DCP is mainly used as an in situ device and laboratory application of DCP, in a mould, was rarely reported, due to the confining effect. In this study, a lightweight cone penetrometer (DLP), with a hammer mass of 2.25 kg that can be used in a CBR mould in the laboratory as well as in the field was used to evaluate the CBR of fine-grained subgrade soils. Strong relationships were found between the CBR values and the dynamic lightweight cone penetration index (DLPI) for eight experimental soils, at four different moisture contents. The results show that CBR values drop and DLPI values increase very significantly when moisture contents increase from optimum to soaked conditions.

Keywords::

• CBR
• DCP
• lightweight dynamic cone penetrometer
• subgrade soil
• fine-grained soil

Acknowledgment

The results presented in this paper are part of an ongoing postgraduate research on pavement materials.