Abstract
PURPOSES: The objective of this study is to determine the milling temperature that minimizes the binder-induced damage to the aggregate; this is achieved by evaluating the temperature dependence of the viscosity of the asphalt binder, with the aim of developing an effective heating process for warm in-place recycling. METHODS : The validity of the indoor test was confirmed by conducting an internal heating test based on the on-site heating test. In addition, the adhesive power of the binder was measured at various temperatures ($30^{\circ}C$, $40^{\circ}C$, $50^{\circ}C$, $60^{\circ}C$, $70^{\circ}C$) via three types of measuring methods. RESULTS: The surface temperature spectrum of field test was slight different with that of laboratory test. But, the spectra of inner temperature between the field and the laboratory was almost similar. Also, the adhesion of the asphalt binder was measured from $30^{\circ}C$ to $70^{\circ}C$. The adhesion of the binder was significantly decreased from $60^{\circ}C$. Contrary to other temperature, the adhesion was slightly changed from $60^{\circ}C$ to $70^{\circ}C$. Also the inner temperature between two different heating methods was shown similar temperature spectra. CONCLUSIONS: The pavement heating temperature spectrum of hot in place recycling method was simulated by a laboratory test. Based on this study, the optimum temperature was $60^{\circ}C{\sim}70^{\circ}C$ for reducing aggregate damage during milling process. The susceptibility heating method developed in this study can be maintained the optimum inner temperature range.
