Author: Shin WuPublisher:
ISBN:
Category : Penetrometers
Languages : en
Pages : 124
Book Description
The Dynamic Cone Penetrometer (DCP) is a simple device for measuring the stiffness of unbound materials. The DCP works by driving a steel rod into bases and soil with a preset amount of energy; the stiffness of unbound materials at different depths can be measured by continuously monitoring the rate of penetration, yielding a stiffness profile. With its ability to collect and analyze date quickly and easily, the DCP compares favorably with other devices used to evaluate an in-situ base and subgrade during construction. The DCP is also the only device available today than can evaluate subgrade quality in all three dimensions. Most highway agencies accept unbound materials in base and subgrade based on density tests. But density is not a measurement of the strength (stiffness) of these materials. Field data collected in this study indicated that accepting the subgrade based on density tests did not guarantee the strength met design requirements. Accepting the base and subgrade based on density is thus one of the weak links in the process of designing and constructing pavement. During the 2003 and 2004 construction seasons, the Ohio Research Institute for Transportation and the Environment (ORITE) collected DCP data from 10 road projects in Ohio. Experience from this study proves that the DCP is a viable alternative device to evaluate in-situ base and subgrade materials during construction. Data collected shows that engineers can use the DCP to quantify the construction quality of the as-built materials. Based on this study, ORITE concludes that adopting DCP testing in unbound material acceptance specifications can greatly improve the monitoring of final product quality and thus enhance pavement performance. This report describes the ORITE study. The report also provides a construction site DCP testing procedure and proposes a set of DCP unbound material acceptance criteria and standards.