Cost Savings and Sustainability Impacts of Using Recycled Materials along Unpaved Roadways

gravel road


Recently completed Iowa DOT and US EPA funded projects found that through the use of recycled aggregates, existing unpaved roads can be maintained using 50–60% less virgin aggregate, thus saving time and costs while maintaining road surface quality. These methods also achieve improved performance, reducing overall environmental impact compared to traditional granular road designs. In this workshop, the results of these projects will be presented to county engineers, as well as a performance and cost assessment tool "BE2ST-in-Roadways" that can be used to assess feasibility in their own counties. This tool includes both Life Cycle Analysis and Life Cycle Cost Analysis to assess the environmental and cost savings, as well as several other factors, to provide a holistic picture, decision-making tool, and quantification of the environmental and cost impacts of implementation of any unpaved road design method.

Workshop Instructors

Bora Cetin

Dr. Bora Cetin is an assistant professor in the geotechnical and geoenvironmental engineering area in the Department of Civil, Construction and Environmental Engineering at Iowa State University. The main focus of his research is improving the sustainability of today`s infrastructure. His research program places a strong emphasis on the sustainable development of geotechnical and transportation infrastructure including unpaved roads. Current research activities are mainly focused on the following fields: (1) Improvement of the sustainability of geotechnical structures; (2) environmental suitability of geotechnical structures built with waste materials and industrial byproducts; (3) performance of unpaved roads under freeze-thaw cycles.

Kristen Cetin

Dr. Kristen S. Cetin is an Assistant Professor at Iowa State University in the Department of Civil, Construction and Environmental Engineering, in the Construction Engineering group. She researches the sustainability and energy performance of the built environment, including how to improve efficiency, reduce energy use, and reduce peak grid loads through a combination of modeling, laboratory and real-world testing methods. Kristen research also includes a focus on smart technologies, and how the use and integration of the Internet of Things (IoT) can enhance performance, and real-time assessment and fault detection.

Jeramy Ashlock

Dr. Jeramy C. Ashlock is the Richard L. Handy Associate Professor of Civil Engineering in the Geotechnical area. His research focuses on improving the performance, longevity, recycling content, and freeze-thaw durability of granular-surfaced roads; improving performance and design/analysis methods for drilled shaft foundations of bridges and structures; improving testing and analysis methods for pile foundations under dynamic and seismic loads; developing new field and laboratory soil testing methods; and nondestructive and geophysical testing methods for soils and pavements, among others. He is currently Chair of ASTM Subcommittee D18.09 on Cyclic and Dynamic Properties of Soils.

Tentative Agenda

8:45 a.m. Registration
9:00 a.m. Welcome and Introduction
9:15 a.m. TR-685: Feasibility of Granular Road and Shoulder Recycling (Dr. Ashlock)
9:45 a.m. Break
10:00 a.m. Sustainability Analysis of Unpaved Road Construction with Recycled Materials in Council Bluffs, IA (Dr. B. Cetin)
10:20 a.m. Break
10:30 a.m. BE2ST-in-Roadways Sustainability Assessment Tool Training - Part 1 (Dr. Cetin)
11:10 a.m. Break
11:20 a.m. BE2ST-in-Roadways Sustainability Assessment Tool Training - Part 2 (Dr. Cetin)
12:00 p.m. Adjourn

For More Information

If you have any questions or need more information, please contact Keith Knapp at 515-294-8817 or


This workshop is provided through funds from the United States Environmental Protection Agency Region 7 and Iowa DOT.