Chromatic and Rheological Characteristics of Clear Road Binders

Abstract

Clear asphalt pavements provide specific functional characteristics to improve safety and climatic conditions in urban areas. The technological development of clear pavements refers to the formulation of special binders with particular chromatic characteristics. This research evaluated three clear binders with different chemical formulations with the aim of establishing the effectiveness of their mechanical properties and chromatic characteristics. Mechanical properties were analyzed by rheological methods. All clear binders were found to have specific dependence on stress levels, time, and temperatures. Different behaviors emerged, depending on the chemical origin of the binders. Chromatic characteristics were quantitatively evaluated by means of a digital image analysis. Red–green–blue as well as hue, saturation, and brightness models were used to determine and compare the chromatic performances of the three binders. The stability of the chromatic characteristics was also estimated with a laboratory aging process. Relationships were found between the chemical origin of the clear binder and its chromatic performance.