Using Simple Tools for Modern Designs
Resilient Modulus is a direct measure of the stiffness of the soil base and subgrade materials underlying a pavement, and is a vital parameter for pavement designs. Commonly used field and laboratory methods to determine this parameter can be time consuming and cost prohibitive. As a result, the resilient moduli of these materials are often conservatively assumed from material type correlations.
An overlooked and underutilized approach to collect real data to estimate this parameter is the dynamic cone penetrometer (DCP). GEODesign routinely includes the DCP as part of our data collection process for pavement design or rehabilitation projects to quickly (~5 minutes per test) estimate resilient modulus. We’ve found the DCP approach can lead to more efficient, lower-cost designs when compared to solely relying on tabulated values.
Broadening the scope of this simple tool has the potential to positively impact the efficiency of pavement designs.
Recently, we participated in an initial research project for the Vermont Agency of Transportation to evaluate a possible expanded use of the DCP to explore the following questions:
- Could DCP testing be used as a tool to reliably measure in-situ resilient modulus of a reclaimed base layer stabilized with an asphalt emulsion or concrete?
- If so, could the data acquired potentially be used for quality assurance purposes during construction of a stabilized base?
The outcome of this specific study identified challenges that are unique to stabilized bases with regards to curing time; and our study outlined a recommended testing program to further evaluate the full effect of cure time on the effectiveness of field-based methods such as the DCP during construction.
GEODesign is pleased to be participating in efforts to explore new and potentially cost-saving uses for this overlooked tool. Regardless of future studies specific to stabilized materials or construction quality control, the DCP remains a valuable, quick, and cost-effective method to provide more economical pavement design and rehabilitation projects.