Experimental Study of Sustainable Asphalt Binder

Abstract

Asphalt pavements are widely used in highways because of their good performance and relatively low construction and maintenance costs. However, the black color of asphalt binder implies that sunlight is not reflected but absorbed; the absorption raises the temperature of the asphalt pavement and impairs its long-term durability. Thermochromic materials can change their colors in response to temperature. These materials reflect solar energy at high temperatures and absorb it at low temperatures. This study investigated the use of thermochromic materials in asphalt binder to develop a thermochromic asphalt binder that would reduce the surface temperature of asphalt pavement during the summer and lead to improved durability. The thermal and phase transition properties of thermochromic materials were characterized by differential scanning calorimetry and modulated differential scanning calorimetry. Comparison measurements showed that the surface temperature of thermochromic asphalt binder was lower than that of the conventional asphalt binder, with a maximum decrease as high as 6.6°C during a typical summer day in Cleveland, Ohio, in the northeastern United States. Experimental results also indicated that the temperature dropped more slowly in the thermochromic asphalts than in regular asphalt subjected to simulated winter temperatures. This finding suggests that compared with traditional asphalt, thermochromic asphalt could delay ice formation on road surfaces; such a delay is an important potential benefit for road safety in cold regions.