Resumen de The Role of Fillers on Cracking Behavior of Mastics and Asphalt Mixtures
Antonio Montepara, Elena Romeo, Marco Isola, Gabriele Tebaldi
Cracking in asphalt mixtures is widely recognized as a mastic-related distress. Polymer modifiers in the asphalt binder or hydrated lime in the filler are commonly introduced in an attempt to enhance the mechanical performance of asphalt mixtures. The role of asphalt modifiers and/or modified fillers on the cracking behavior of asphalt mixtures is extremely complex and has not been fully explained. The addition of the same modifier to different binders has been shown to lead to contrasting results in terms of both fatigue resistance and low-temperature cracking. Accurate description of strain evolution and distribution in mastics and asphalt mixtures is essential for revealing significant information on the influence of binder/filler properties on Hot Mix Asphalt (HMA) macroscopic behavior.
The work presented in this paper focuses on the evaluation of the influence of fillers on HMA cracking response. Fracture properties of 16 different asphalt mixtures composed by the combination of four different fillers and four asphalt binders, including unmodified and polymer modified binders, were evaluated using a visco-elastic fracture mechanics-based crack growth law (1). The cracking behavior of mastics was investigated using a modified Direct Tension Test (DTT). Strain localization and damage distribution were observed using a Digital Image Correlation System (DIC) capable of accurately capturing localized or non-uniform stress distributions in asphalt materials.
Experimental results indicate that tensile failure properties of the mastic are strictly correlated to HMA failure limits for either unmodified or polymer modified mixtures. It was observed that strain localization and damage distribution in asphalt mixtures is strictly dependent on the physico-chemical _____________________________________ 1Professor, University of Parma, Parma, Italy 2Associate Researcher, University of Parma, Parma, Italy 3PhD Student, University of Florida, Gainesville, FL 4Assistant Professor, University of Parma, Parma, Italy The oral presentation was made by Dr. Romeo
