Iowa Department of Transportation
Iowa Highway Research Board
Chris Williamsrwilliam@iastate.edu email >
About the research
The opportunity to produce a high-value material derived from vegetable oil from the Midwest creates a tremendous economic opportunity to replace a dangerous and carcinogenic material in butadiene, which is derived from crude oil petroleum. The majority of butadiene is imported to use for subsequent production of polymers or is contained in polymers imported to the US. Development of the biopolymer technology for asphalt paving was sponsored by the Iowa Highway Research Board (IHRB) under a special funding mechanism for high-risk/high-potential-pay-off research. The biopolymers developed by Iowa State University were found to be an excellent alternative to the polymers currently used.
Since the conclusion of the first phase of this study in April 2014, a ton-per-day pilot plant was designed and built at Iowa State University’s BioCentury Research Farm, west of Ames, at a cost of more than $6 million. The pilot plant was installed in late 2015, winterized for the 2015–2016 winter, and reopened in Spring 2016.
The research team worked since the completion of the Phase I IHRB project in getting the pilot plant working and correctly calibrated. The Bio-Polymer Processing Facility underwent rigorous troubleshooting and upgrades during 2016 and became capable of producing biopolymers in sufficient quantities to conduct field demonstration paving projects. Research done during this work led to optimized formulations of biopolymer and furthered the march toward the implementation of biopolymer for field demonstration projects.
Due to the high number of mix designs that include reclaimed or recycled asphalt pavement (RAP), the biopolymer was transformed with a rejuvenator into a liquefied state to perform easier and more efficient blending with neat binders. From this new biopolymer/rejuvenator combination, called BioMAG, one test section and two demonstration projects were paved at the National Center for Asphalt Technology (NCAT) Test Track at Auburn University in Alabama and two sites in Iowa. The section at the NCAT Test Track is performing well against rutting and cracking.
Currently, additional data are being collected about other distresses. For the two demonstration projects in Iowa, mix and binder were collected from the Altoona, Iowa site. Full mix and binder characterization have shown that BioMAG performs well in RAP mix designs and improves resistance against low temperature cracking and rutting.