CTRE is an Iowa State University center, administered by the Institute for Transportation.

Address: 2711 S. Loop Drive, Suite 4700, Ames, IA 50010-8664

Phone: 515-294-8103
FAX: 515-294-0467

Website: www.ctre.iastate.edu/

Iowa State University--Becoming the Best

MnDOT LRRB Aggregate Road Surface Rejuvenation


Principal investigators:

Project status


Start date: 01/30/13
End date: 03/31/15


Report: Aggregate Road Surface Rejuvenation (NA pdf) April 2015

Related publication: Blending Fines into Existing Loose Gravel Costs Less Than Regraveling Feb 2015


Sponsor(s): Minnesota Department of Transportation

About the research


Aggregate surfaced roads become coarser and coarser after a few years of service due to an inherent problem—dust emission. Fines in the surfacing material are kicked up by traffic and blown away by the wind as fugitive dust. One of the alternative rejuvenation methods is to replenish the missing fines to restore the gradation and plasticity of the in situ material. Savings in the material and cost could in return benefit the environment and financial condition of the jurisdiction.

Control and experimental test sections were established in three counties of Minnesota and performance of the sections were assessed using methods including cross-section profile change surveys, gravel loss and loose aggregate measurements, gravel road condition ratings, International Roughness Index estimation, and field observations. Experimental sections in Jackson County did not perform satisfactorily. However, one of the test sections in Beltrami County performed favorably well. A five-year-cycle benefit-cost analysis revealed that a 20 percent cost savings was also achievable in that particular section. Another trial in Olmsted County tested whether modified Class 5 limestone aggregate is appropriate for gravel road surfacing.