Adoption of New Products 1 MnROAD Lessons Learned MnROAD and the Adoption of New Products in Pavements MnROAD Lessons Learned – December 2006 Derek Tompkins, Prof. Lev Khazanovich University of Minnesota MnDOT Contacts: John Siekmeier 1 Abstract Throughout its decade of operation, MnROAD has become a major resource in the pavement community for test track expertise, pavement data, and pavement research. However, one overlooked benefit of MnROAD’s first phase of operation is the effort of MnROAD engineers to introduce, develop, and encourage the use of new technologies and techniques for pavement engineers. While the list of new products tested and/or developed at MnROAD is extensive, this brief will focus on three products and the influence of those products outside of MnROAD: the Dynamic Cone Penetrometer, used to estimate the strength of subgrades; Ground Penetrating Radar, used in pavements to assess, among other things, layer thicknesses and subsurface conditions; and Continuous Compaction Control, which involves continuously measuring soil compaction and adjusting the needed force to compact the soil. These three highlights emphasize the ability of MnROAD to: 1. serve as a test facility for pavement and pavement foundation experiments, 2. develop new technologies and procedures for pavement engineering, 3. contribute in a significant manner to pavement engineering both at a local and national level. It is hoped that this brief exposes the reader not only to a few past accomplishments of MnROAD in new technologies but will give a better idea of the promise and ability of MnROAD in the development and adoption of these technologies. 2 Background This brief will explore three examples of MnROAD’s involvement in the development of significant tools in pavement engineering. Before detailing MnROAD’s involvement in these tools, a general introduction to each tool is provided. 2.1 Dynamic Cone Penetrometer The dynamic cone penetrometer (DCP) is a tool that has been used in various forms for centuries to test soils, beginning in 17 th century Germany. The DCP as used by MnDOT is a variation of a version that has existed since the late 1950s. Since that time, pavement engineers have used the DCP as a quick, portable means of estimating the soil shear strength or modulus of elasticity of a given subgrade. To conduct a DCP test, a drop hammer of a specific weight is dropped onto an anvil with a pointed tip. The penetration of the tip is recorded as an indexed value (usually in terms of mm/blow), and the engineer can correlate this index to a specific soil property for a given soil/base type. While values determined using DCP are not as accurate as those of other more complicated tests, engineers have used the DCP for some time due to its portability and ease of use in assessing in situ foundation characteristics, including uniformity of compaction.