Examining the Feasibility and Properties of Biobased Paving Binders: Soy Soapstock

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Examining the Feasibility and Properties of
Bio-based Paving Binders Soy Soapstock

• John E. Haddock, Ph.D., P.E.
• Associate Professor
• School of Civil Engineering
• Purdue University
• West Lafayette, IN

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Acknowledgements

• Joseph Seidel, P.E.
• Graduate Research Assistant
• School of Civil Engineering
• Bernie Tao, Ph.D.
• Professor
• School of Agricultural and Biological
  Engineering

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A Century of Asphalt
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Crude Oil Production
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Asphalt Pricing Volatility
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Current Climate

• 94 of U.S. paved roads are paved with asphalt
• Refined from a nonrenewable resource
• Refining methods can make asphalt scarce and more
  expensive
• Enormous demand for maintenance applications

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Possible Solution

• Time to examine renewable bio-alternatives as
  binding agents in flexible pavement systems.

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Technical Feasibility
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Technical Feasibility
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Technical Feasibility
E

• Shell

Ecopave
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Economic Feasibility
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Economic Feasibility

• Soapstock Supply

• Asphalt Demand

• Availability will increase with increased
  commercial use of soybean oil and soy-based
  resins
• Estimated 0.5 million tons/yr produced

• World Demand for Asphalt in 2004 about 110
  million tons
• 85 toward paving products
• United States represented 36 of the world demand

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Economic Feasibility

• Will it raise food prices?
• What about additional fuel and fertilizer use?
• Since soapstock is a byproduct of soybean oil
  processing, its utilization will not be an
  impetus for growth
• Will it compete with existing/future markets?
• Protein source in animal feed (existing)
• Biodiesel (possibly)

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Environmental Feasibility

• Currently used as an environmentally friendly
  dust suppressant
• Known for its biodegradability and low volatility
  
• As a flexible binder material it will need to be
  evaluated using the standardized tests

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Desired Binder Attributes

• Workable
• Stable (oxidation resistance)
• Durable
• Flexible
• Fatigue resistant
• Tolerant to thermal changes
• Resistant to moisture damage

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Research Methodology

• Testing various material constituents using a
  statistical approach

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Research Overview
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Conclusions

• The use of soybean soapstock as a pavement binder
  appears to be technically feasible
• Current supply is not equivalent to demand, but
  could work in a regional approach
• Appears to be a cost-effective alternative to
  asphalt binders
• Currently is environmentally friendly
• Questions about possible environmental damage
  from additional cultivation

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Questions?