In this paper, a 2D-wavelet approach is proposed to characterize the pavement texture acquired from the 3D laser scanner. The texture is decomposed into nine levels (from 0.1 mm to 25.6 mm) to extract the feature at multiscale. The Relative Energy (RE) and 2D-Entropy are calculated as indicators to represent the mixture surface texture distribution properties. Through conducting the 2D-wavelet decomposition on eight types of mixtures, it is found that the decomposition results perform well in recognizing the aggregates and predicting the gradation distribution. A wearing test for 100 h is also conducted and the results reveal that the mean profile depth (MPD) is highly correlative to the energy of the macro-texture while the RE and 2D-Entropy of the micro-texture decrease during the polishing process. Moreover, the mixture surface texture variates differently in the two directions: the RE of micro-texture deteriorate faster in the y-direction (the wheel movement direction) than the x-direction. The results show that the indicators can be used to measure the pavement texture variation due to traffic wear during service life, demonstrating that the novel 2D-wavelet approach the potential to evaluate road performances, such as skid and wear resistance.

Asphalt pavement cracks easily in low-temperature environments. In order to address the problem, phase-change material (PCM) microcapsules working at 0–10°C are used to replace some of the aggregates in asphalt. In this study, PCM microcapsules with a high-temperature epoxy resin adhesive as reinforcement phase were prepared by using $n$ -tetradecane/tetradecanol as the core material and melamine-urea-formaldehyde as the wall material. The reinforced PCM microcapsules were blended into the asphalt modified by styrene-butadiene-styrene block copolymer (SBS) modified asphalt, the PCM microcapsules were used to replace part of the same amount of the coarse aggregate. The results depict that the reinforced PCM microcapsules can satisfy the requirements of both immersion Marshall test and freeze-thaw splitting test. Above all, asphalt mixtures containing reinforced PCM microcapsules have been proved acceptable via dynamic stability tests. The bending beam rheometer test results imply that asphalt mixture containing PCM microcapsules revealed good crack resistance at low temperatures. Compared with the asphalt mixture sample in the reference experiment, the temperature difference of that containing the reinforced PCM microcapsules could reach 2.1°C, indicating a promising application prospect.

Low-temperature phase change material (PCM) is a material that stores additional heat at elevated temperatures and releases energy when the temperature is below the limit. A way to solve the low-temperature disaster of asphalt pavement is desired to be developed. In this article, a two-component organic low-temperature PCM was encapsulated by melamine-urea-formaldehyde resin and finally reinforced with polypropylene. The reinforced PCM microcapsules were mixed with 70^# SBS (Styrene-Butadiene-Styrene) modified asphalt in SMA-10 (Stone Matrix Asphalt-10) to form aggregates. The results showed that after adding 6.0% (w/w) reinforced PCM microcapsules, there was a significant delay compared to a blank sample with a maximum temperature difference of 1.8 °C when the temperature dropped to 0 °C, which proved that this method has a good potential in resisting low temperature disasters on asphalt pavement and deserves further improvement.