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High Performance Concrete Pavements Project Summary

Chapter 15. IOWA 6 (Various Locations)


Iowa State University, in cooperation with Iowa DOT and Iowa Fly Ash Affiliates (IFAA), started full-scale field tests in 2002 to develop and implement practical guidelines for soil stabilization with a wide range of fly ashes. This research will not only benefit the paving industry by emphasizing the importance of subgrade uniformity, but it will develop knowledge of successful design and application of soil stabilization with fly ash materials.

Study Objectives

The research has four primary objectives (White 2002):

  1. Evaluate and document the influence of subgrade uniformity on pavement performance from studies of past and test sections selected in this study.
  2. Determine from field test sections and laboratory analysis how various raw fly ashes, hydrated fly ashes (HFA), and conditioned fly ashes (CFA) in combination with the wide range of Iowa soil types will bring about uniform properties for subgrade support.
  3. Recommend design and construction procedures and develop a Ash Stabilization Guide.
  4. Create a technology transfer seminar to disseminate the knowledge.

Project Design and Layout

Several potential fly ash stabilization projects including sections of US highways 63 and 330 have been identified for this study. Field testing will be conducted to determine engineering properties of subgrade soils, such as classification, stiffness, strength, density, and moisture content before and after stabilization (White 2002). Laboratory testing will be conducted on various ash/soil mixtures to evaluate the effects of ash on compressive strength, volumetric stability, and soil index properties of subgrade soils (White 2002).

State Monitoring Activities

At the time of this report, the planned monitoring activities are yet to be determined.

Preliminary Results/Findings

No preliminary results or findings are available.

Points of Contact

Mark Dunn
Iowa Department of Transportation
800 Lincoln Way
Ames, IA 50011
(515) 239-1447

David J. White
Iowa State University
Center for PCC Pavement Technology
2901 S Loop Drive, Suite 3100
Ames, IA 50010-8632
(515) 294-8103


White, D. W. 2002. Field Trials of Guidelines for Soil Stabilizers of Non-Uniform Subgrade Soils - Proposal. Iowa State University, Ames.

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Updated: 09/21/2015
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