Biofuel CoProduct Uses for Pavement Geo-Materials Stabilization Final Report

Using biomass as a sustainable, renewable energy source can be part of a solution for reducing dependence on fossil fuel–based energy and mitigating global warming, and both the production and use of biofuels made from biomass have increased. Biofuel production creates not only biofuel or ethanol, but also co-products containing lignin, modified lignin, and lignin derivatives. The use of these co-products to help stabilize pavement soils and other geo-materials has been studied over the past decades. However, most lignin-related soil stabilization studies have investigated sulfite lignins (lignosulfonates) derived from the paper industry, while the lignins obtained from biofuel or ethanol production are sulfur-free. The use of lignin-based BCPs in pavement geo-materials stabilization need to be investigated, as it is hypothesized that stronger geo-materials stabilization may be achieved and may reduce the amount of geo-materials needed to stabilize soils. Newer uses of biomass-derived lignin could also provide additional revenue streams for bio-based products and the bioenergy industry Disciplines Civil and Environmental Engineering This report is available at Iowa State University Digital Repository: http://lib.dr.iastate.edu/intrans_techtransfer/61 Biofuel Co-Product Uses for Pavement Geo-Materials Stabilization Final Report April 2010 Sponsored by the Iowa Highway Research Board (IHRB Project TR-582) and the Iowa Department of Transportation (InTrans Project 08-316) About the Institute for Transportation The mission of the Institute for Transportation (InTrans) at Iowa State University is to develop and implement innovative methods, materials, and technologies for improving transportation efficiency, safety, reliability, and sustainability while improving the learning environment of students, faculty, and staff in transportation-related fields. 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The preparation of this (report, document, etc.) was financed in part through funds provided by the Iowa Department of Transportation through its “Agreement for the Management of Research Conducted by Iowa State University for the Iowa Department of Transportation,” and its amendments. The opinions, findings, and conclusions expressed in this publication are those of the authors and not necessarily those of the Iowa Department of Transportation. Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. IHRB Project TR-582 4. Title and Subtitle 5. Report Date Biofuel Co-Product Uses for Pavement Geo-Materials Stabilization April 2010 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. Kasthurirangan Gopalakrishnan, Halil Ceylan, and Sunghwan Kim InTrans Project 08-316 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Institute for Transportation Iowa State University 2711 South Loop Drive, Suite 4700 Ames, IA 50010-8664 11. Contract or Grant No. 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered Iowa Highway Research Board Iowa Department of Transportation 800 Lincoln Way Ames, IA 50010 Final Report 14. Sponsoring Agency Code 15. Supplementary Notes Visit www.intrans. iastate.edu for color PDF files of this and other research reports. 16. Abstract The production and use of biofuels has increased in the present context of sustainable development. Biofuel production from plant biomass produces not only biofuel or ethanol but also co-products containing lignin, modified lignin, and lignin derivatives. This research investigated the utilization of lignin-containing biofuel co-products (BCPs) in pavement soil stabilization as a new application area. Laboratory tests were conducted to evaluate the performance and the moisture susceptibility of two types of BCP-treated soil samples compared to the performance of untreated and traditional stabilizer-treated (fly ash) soil samples. The two types of BCPs investigated were (1) a liquid type with higher lignin content (co-product A) and (b) a powder type with lower lignin content (coproduct B). Various additive combinations (co-product A and fly ash, co-products A and B, etc.) were also evaluated as alternatives to stand-alone co-products. Test results indicate that BCPs are effective in stabilizing the Iowa Class 10 soil classified as CL or A-6(8) and have excellent resistance to moisture degradation. Strengths and moisture resistance in comparison to traditional additives (fly ash) could be obtained through the use of combined additives (co-product A + fly ash; co-product A + co-product B). Utilizing BCPs as a soil stabilizer appears to be one of the many viable answers to the profitability of the bio-based products and the bioenergy business. Future research is needed to evaluate the freeze-thaw durability and for resilient modulus characterization of BCPmodified layers for a variety of pavement subgrade and base soil types. In addition, the long-term performance of these BCPs should be evaluated under actual field conditions and traffic loadings. Innovative uses of BCP in pavement-related applications could not only provide additional revenue streams to improve the economics of biorefineries, but could also serve to establish green road infrastructures. 17.