Evaluation of Otta Seal Surfacing for Low Volume Roads in Iowa

Project status

In progress

Start date: 05/01/14
End date: 06/30/18


Principal investigators:

Co-principal investigators:

About the research

Iowa has approximately 72,800 miles of unpaved secondary roads with very low daily traffic volumes. Iowa's County secondary road departments spent more than $72 million for aggregate replacement in 2008 alone. Otta seals may be able to provide an alternative to a traditional bituminous surface treatment as well as an alternative to maintaining granular roads with constant replenishment of granular materials. This project will: evaluate the feasibility of Otta seals as an alternative surface treatment on low-volume roads using local aggregate, including lowerquality aggregates; evaluate the cost-effectiveness and performance of Otta seals; develop a guide for road selection; identify local projects for field demonstrations; and, evaluate installed Otta seal performance through seasonal changes and laboratory testing.



  • Iowa Department of Transportation
  • Iowa Highway Research Board