Most states have plans to change to PG in the near future. Early this summer Minnesota, Wisconsin and Iowa DOT's met with most of the AC producers for this region. After several meetings an agreement was arranged to proceed to the performance grading system for the three state region. Additionally all three states selected typical performance grades which would be in general use. This agreement was reached to provide uniformity for the producers within the region, ensure adequate supply, standardize testing and classification, and maintain reasonable pricing for the material.
Polymer modified binders do have a significant cost increase over current asphalt.
Performance grading is designated by two numbers representing the high and low temperature extremes where AC is intended to perform. These relationships are not always direct. Performance on the six PG tests vary from one supplier to the next, depending on their crude oil source. Most asphalt cement producers have indicated that the three AC's mentioned above are readily available at little or no increase in cost under the new classification system. The first year under the new system will incorporate all the required testing parameters with a tolerance between labs.