Determination of the Optimum Base Characteristics for Pavements (TR-482)

Project Investigators

Charles Jahren, David White


Pavana Vennapusa

Project Schedule

Aug 2002 to Feb 2004


Iowa Highway Research Board


base characteristics, drainage, in situ characterization, in situ testing, pavement, stability, subgrade, subsurface layers

Project Description

In recent years, it has become apparent that the design and maintenance of pavement drainage extends the service life of pavements. Most pavement structures now incorporate subsurface layers. Part of the function of these subsurface layers is to drain away excess water, which can be extremely deleterious to the life of the pavement. To assure the effectiveness of such drainage layers after they have been spread and compacted, simple, rapid, in-situ permeability and stability testing and end-result specification are needed. This report includes conclusions and recommendations related to four main study objectives:

  1. Determine the optimal range for inplace stability and in-place permeability based on Iowa aggregate sources;
  2. Evaluate the feasibility of an air permeameter for determining the permeability of open and well-graded drainage layers in situ;
  3. Develop reliable end-result quality control/quality assurance specifications for stability and permeability;
  4. Refine aggregate placement and construction methods to optimize uniformity.