COMPARATIVE EVALUATION OF LABORATORY COMPACTION DEVICES BASED ONTHEIR ABILITY TO PRODUCE MIXTURES WITH ENGINEERING PROPERTIES SIMILAR TO THOSE PRODUCED IN THE FIELD

A major objective of the asphalt aggregate mixture analysis system (aamas), sponsored by the national cooperative highway research program (nchrp), is to ensure that laboratory-molded mixtures will befabricated in a manner that will adequately simulate field conditions and, consequently, yield reliable engineering properties. This paper describes a field and laboratory study that evaluates the ability of five compaction devices to simulate field compaction. The compaction devices evaluated were selected on the basis of their availability, uniqueness in mechanical manipulation of the mixture, and potential for use by agencies responsible for asphalt mixture design. The devices evaluated are (a) the mobile steel wheel simulator, (b) the texas gyratory compactor, (c) the california kneading compactor, (d) the marshall impact hammer, and (e) the arizona vibratory-kneading compactor. The ability of the five laboratory compaction devices to simulate field compaction is based on the similarity between engineering properties (resilient moduli, indirect tensile strengths and strains at failure, and tensile creep data) of laboratory-compacted samples and field cores. Five projects were selected for this study.Project locations were in texas, virginia, wyoming, colorado, and michigan. The field compaction procedure used at the sites was the standard procedure used by the state highway departments responsible for the highways involved. Overall, the texas gyratory compactor demonstrated the ability to produce mixtures with engineering propertiesnearest those determined from field cores. The california kneading compactor and the mobile steel wheel simulator ranked second and third, respectively, but with very little difference between the two. The arizona vibratory-kneading compactor and the marshall impact hammer ranked as least effective in terms of their ability to produce mixtures with engineering properties similar to those from field cores. This paper appears in transportation research record no. 1228, Asphalt mixtures and asphalt chemistry.