(Submitted for journal publication)
M.P. Wagoner, W.G. Buttlar, G.H. Paulino
Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Newmark Laboratory, 205 North Mathews Avenue, IL 61801, USA
P. Blankenship
SemMaterials, L.P., P.O. Box 1875, 4027 E. 37th Street North, Wichita, KS 67201-1875
Abstract
The calibration of pavement models to field observations can be an important step in refining the model to accurately predict pavement response. The challenge with field calibration has been obtaining the materials properties with laboratory tests that have the capability to use specimens fabricated from field cores. Unless complicated fabrication procedures are used, field cores limit the specimen geometry to cylindrical shapes and thin cross sections due to the relatively thin pavement lifts typically used during pavement construction. Recent developments in fracture testing of HMA concrete have enabled the development of a testing suite that captures both continuum and material separation properties from field cores. Two specimen geometries, indirect tension and disk-shaped compact tension, were utilized for the testing suite. The testing suite was developed for use with a National Science Foundation project to investigate reflective cracking mechanisms. With this project, five material properties were obtained from the laboratory to characterize the hot-mix asphalt concrete layers. To illustrate the application of the testing suite, a single project was selected with three test sections. The testing suite was successful in determining the viscoelastic response of the materials through creep compliance and complex modulus testing. These two tests ranked the materials according to the asphalt binder grades. The material separation parameters appeared to be influenced by the asphalt binder grade. The fracture energy obtained with the disk-shaped compact tension test appeared to rank the materials according to the expected resistance to fracture better than the indirect tensile strength. Future work will include integrating the material properties with finite element analysis to provide a detailed analysis of the pavement structure to determine the mechanisms that initiate the reflective cracks.
KEY WORDS: Reflective Cracking, Disk-shaped Compact Tension, Tensile Strength, Fracture, Complex Modulus, Asphalt, Overlay.