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.
In order to eliminate the deficiencies of the solvent-based cold patch asphalt mixture, this paper presented the cold patch asphalt mixture modified with waterborne epoxy resin (WER). Firstly, the new evaluation method were put forward based on its technical features and application requirements. Then the influence of different compositions and contents of WER on the cold patch asphalt liquid was evaluated by laboratory tests. Further, the pavement performance and workability of WER modified cold patch asphalt mixture were systematically evaluated. The results show that (i) WER can significantly improve strength, moisture susceptibility, high temperature performance and cohesion. However, the inappropriate addition may lead to poor storability and low temperature performance. So the optimal WER content is recommended 1.2–1.8 wt%, and its component ratio of epoxy resin to curing agent is 3:1. (ii) Different WER components produce different performances of mixture. The EP-20 + HGC brings about higher curing strength, excellent high temperature performance and storability. In comparison, the mixture modified with EP-20 + HGA owns preferable initial strength and moisture susceptibility. In the practical project, it is necessary to choose suitable WER considering the performance deficiency of cold patch materials and maintenance needs.
22 July 2022 in Construction and Building Materials