Development of a Test Method to Measure the Quality of Milling Operations in Asphalt Pavements (05-0903)**
Victor Lee Gallivan, Gallivan Consulting, Inc.
Joseph F. Gundersen, Indiana Department of Transportation

Cold milling operations have been utilized for over two decades in Indiana but little attention was given to the “quality” of the operations. Several alternatives for evaluating surface macrotexture were considered as a quality measure. ASTM E 965-96 was selected as the best existing procedure on which to base evaluation of milled surfaces. The Indiana DOT developed test method ITM 812-03T to make the ASTM procedures workable for milled surfaces. The initial quality of Hot Mix Asphalt (HMA) construction directly affects the return on investment with the long-term performance and the service life of a transportation facility. The initial quality of construction is directly dependent upon the quality of the aggregates and binders and the production and laydown operations. Construction factors affect the initial quality including surface preparation procedures that is the removal of distressed materials (cold milling) to develop a stable working platform on which Hot Mix Asphalt materials can be placed. The Indiana Hot Mix Asphalt contractors were experiencing numerous problems meeting the volumetric and density quality requirements on highway construction projects. A significant number of HMA mixtures were either being accepted with partial payment or replaced prior to being accepted. Investigation of the problem included observing the contractor’s Certified HMA Plant Production operations, mixture components (i.e., aggregates, binders, etc), mixture transportation, laydown and compaction, and also mixture sampling procedures. It was discovered that more problems existed when cold milling of the existing surface was included in the project. A solution to the noted issues resulted in the development of improved milling design and construction requirements, which includes quality measurements techniques for the milling operations. Key Words: Cold Milling, HMA, Hot Mix Asphalt, Quality, Macrotexture, Milling