North Central Pavement Research and
Implementation Coordination Partnership

Workshop on Underlying Pavement Stabilization
Madison, Wisconsin - October 8, 2008

WisDOT’s Policy for Use of Select Materials in Subgrades
(presented by Bob Arndorfer, WisDOT)
This presentation gives a brief history of WisDOT’s select materials policy, which was developed in the mid 90s by a team established to address road construction cost overruns attributed to difficulties with the subgrade. The current design details and policy guidelines are then presented, along with an overview of five related research projects and an implementation study.

Application of Laboratory Evaluation to Develop Stiffness Values and Layer Coefficients for Design
(presented by Dante Fratta, UW-Madison)
This presentation presents results of several research efforts: 1. A comparison of low-strain elastic modulus as derived from seismic tests with traditional laboratory resilient modulus. 2. Measuring elastic wave velocities in a small box. 3. Large-scale model experiments to determine the Gravel Equivalency of recycled pavement material and road surface gravel with and without fly ash. 4. Attempts to evaluate the use of geogrid in a flexible pavement system.

Guidelines and Best Practices for Selecting the Proper Subgrade/Base Stabilization Alternative
(presented by Stan Vitton, Michigan Tech University)
This presentation covers the state of stabilization standards from AASHTO, the military, and other sources, covering different stabilization techniques (e.g. compaction, geotextiles, paper sludge), additives (e.g. portland cement, lime, fly ash), and related issues such as sustainability. The presentation also addresses the use of clegg hammers to measure soil density.

Construction Quality Control Practices for Evaluation of In-situ Stiffness and Material Variability
(presented by John Siekmeier, Mn/DOT)
This presentation provides an overview of Intelligent Compaction research and techniques at Mn/DOT, including compaction testing, the move from measuring density to measuring modulus, new field testing techniques (e.g. light-weight deflectometers), intelligent compaction equipment (e.g. IC rollers that measure and document soil stiffness), and data management and geostatistics.

Performance of Michigan’s Stabilized Base Projects
(presented by Andy Bennet, MDOT)
This presentation describes MDOT’s Special Provision for Stabilized Open Graded Drainage Coarse and stabilized base projects constructed between 1990 and 1995 (two stabilized with cement, and 11 with asphalt, usually asphalt emulsion), including a 2006 field investigation into the current performance of these pavements and a cost comparison of open graded drainage coarse.