Abstract
To reduce the temperature of asphalt pavement and improve the antirutting performance of asphalt mixture, a thermal-resistant asphalt mixture (TRAM) was produced, in which a certain proportion of mineral aggregate was replaced by ceramic (CE) or floating beads (FB) featuring low thermal conductivity. Firstly, a parallel plate test was developed to test the thermal conductivity of asphalt mixture added with different thermal-resistant materials. Secondly, the illumination test system was designed to study the visual cooling effect of different TRAM by imitating the natural environment. Finally, the effect of different thermal-resistant materials on asphalt pavement performance was evaluated. The results show that the addition of thermal-resistant materials can reduce the thermal conductivity and the temperature of asphalt mixture. The cooling effect of CE75 and CE100 (coarse aggregate substituted by 75% and 100% CE, respectively) is superior to other aggregates. The temperature reduction rates of CE75 and CE100 reache 6.6°C and 6.8°C, respectively. For FB50 and FB75 (fine aggregate substituted with 50 and 75% FB, respectively), the cooling effect of them reaches 3.9°C and 4.5°C, respectively. In addition, the CE and FB can improve the antirutting performance of asphalt mixture by reducing the temperature inside the pavement. The high-temperature performance of CE75 and FB75 is the best. With the increase of thermal resistance materials, the low-temperature cracking resistance of asphalt mixture decreases gradually. The failure strain of mixture added with 100% thermal resistance materials is close to the lower limit of Chinese specification. The water stability of different TRAM changes with various test methods. Taking into account the results of pavement performance and the cooling effect, the substitution proportion of CE and FB for TRAM is proposed as 50%∼75%, respectively.
Highlights
Asphalt mixture is a kind of black material, which highly absorbs solar radiation [1]. e temperature of asphalt pavement is higher than atmospheric temperature, leading to the occurrence of high-temperature deformation
The absorption of heat energy in asphalt pavement leads to the raising of pavement temperature and releases a lot of heat to the surrounding environment, which results in rutting disease of pavement and “urban heat island effect” [2,3,4,5,6,7,8,9,10]. erefore, improving the temperature field of asphalt pavement structure is of great advantage for pavement rutting resistance and mitigation of “heat island effect.”
When the substitution proportion is more than 75%, its cooling effect is relatively poor. at may be caused by the less asphalt content which results in inadequate compaction of asphalt mixture. e heat insulation effect of asphalt mixture gets poorer when the aggravate structure is loose, so the proportion of floating beads (FB) should not be too large
Summary
Asphalt mixture is a kind of black material, which highly absorbs solar radiation [1]. e temperature of asphalt pavement is higher than atmospheric temperature, leading to the occurrence of high-temperature deformation. Erefore, improving the temperature field of asphalt pavement structure is of great advantage for pavement rutting resistance and mitigation of “heat island effect.”. Due to the low thermal conductivity, the thermal-resistant materials used in asphalt mixture have drawn more and more attention. Heat-reflective layer and thermal resistance technology have been used to lower the pavement temperature [11]. A heat-reflective layer improves the reflectivity and radiation efficiency of pavement surface and lowers the pavement temperature by preventing external heat from transferring into pavement structure [12,13,14,15,16,17,18,19]. The application of coating has been limited due to the defects in cost, technology, and durability. e thermal resistance technology for reducing the pavement temperature is adding thermal resistance material, which could reduce the temperature of Advances in Materials Science and Engineering pavement effectively. e thermal resistance materials include ceramic, pottery sand, diatomite, bauxite, and refractory stone [20,21,22,23,24]
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