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Research Projects (2003-04)

Identifying Number


Project Title

Evaluation of Moisture Susceptibility of Asphalt Mixtures Containing Bottom Ash


University of Wyoming

Project Investigator

Khaled Ksaibati
University of Wyoming

External Project Contact

Mr. James Murphy, President
P.O. Box 4098
1945 Schoonover Street
Gillette, WY 82717-4098

Project Objective

Conduct applied research to evaluate the performance of bottom ash asphalt mixes.

Project Abstract

In the United States, coal fired electric power plants consume more than 800 million short tons of coal each year. This consumption produces over 70 million short tons of coal ash, more than 20 percent of which is bottom ash. However, nearly 70 percent of bottom ash remains unused. The majority of bottom ash is disposed of in landfills, which are becoming limited. A rising consciousness of the environment makes it more difficult to find locations to dispose of the ash. Bottom ash has recently been used in constructing transportation facilities. However, the use of bottom ash in asphalt mixture is still in early stages. Several laboratory studies indicated the feasibility of incorporating bottom ash in asphalt mixes. In fact, a recent study indicated that bottom ash may improve the moisture resistance of asphalt mixes. It is important that the field performance of bottom ash asphalt mixes is investigated to confirm laboratory findings. This study will:

  • Evaluate the field performance of two experimental sections containing bottom ash. The first section is in Gillette, Wyoming while the second one is at the Wyodak power plant. The evaluation will include non-destructive structural evaluation in addition to distress survey. Field evaluation results will be correlated to laboratory findings.
  • Perform laboratory chemical analysis on mixes with bottom ashes to confirm the improvement in moisture resistance due to bottom ash addition. The testing will include nitrogen thermograms as well as rheology testing.

Task Descriptions

  • Perform a distress survey on the experimental sections.
  • Perform falling weight deflectometer testing on the experimental sections.
  • Perform chemical analysis on bottom ash asphalt mixes.
  • Utilize back calculation programs in determining the modulus of elasticity of in-service bottom ash asphalt mixes.
  • Summarize the findings from the various testing.
  • Compare the findings from the control and bottom ash test sections.
  • Perform a comprehensive statistical analysis on the collected data.
  • Deliver a final MPC report summarizing the findings of the study.
  • Submit a TRB technical paper.

Milestones, Dates

Starting Date: July 1, 2003
Finishing the Analysis: May 31, 2004
Deliver a Fina MPC Report: June 30, 2004
Submit a TRB Paper: August 1, 2004
Ending Date: June 30, 2004

Student Involvement

One undergraduate student

Relationship to Other Research Projects

The University of Wyoming has performed several studies on bottom ash. These studies will guide the activities of this new study.

Technology Transfer Activities

Transportation Departments in Region 8.

Potential Benefits of the Project

Increase the effective utilization of waste bottom ash materials in asphalt pavements in the Mountain-Plains region.

TRB Keywords

Pavement performance, moisture susceptibility, bottom ash, asphalt mixes

NDSU Dept 2880P.O. Box 6050Fargo, ND 58108-6050