Risk Management of Low Air Void Asphalt Concrete Mixtures

Various forms of asphalt pavement distress, such as rutting, shoving, and bleeding, can be attributed, in many cases, to low air voids in the mixtures during production and placement. The occurrence of low air void contents during plant production may originate as a result of an accidental increase in binder content or mix fines (or both). When low air voids are encountered during production, the specifying agency must decide whether to require the material that has already been placed to be removed and replaced or whether it can be left in place with a reduction in pay. This decision involves a performance risk to the department of accepting a mix that may perform poorly and a monetary risk to the contractor who may be required to remove and replace a mix that could perform satisfactorily. Consequently, the Indiana Department of Transportation (INDOT) initiated this research project to develop an objective decision-support tool for dealing with such events that is based on projected rutting performance of the pavement system.