【摘要】 传统的路面热惯性较大,吸热、储热能力强,加剧了城市热岛效应的发展。近年,使用冷路面技术降低城市热岛效应的研究不断增加。基于路面反射率的冷路面技术,分析了反射路面的降温机理及其对室外热环境的影响。分析了太阳热辐射峰值、面层材料、热反射涂层、面层材料含水量及城市构造这5种因素对路面温度的影响。结果表明:太阳辐射峰值随季节呈规律性变化,由于峰值对日最高温度的作用效果不同,使路面夏季降温效果明显优于冬季,既满足夏季降温又降低对冬季路面的不利影响;面层材料对路面温度的作用效果与材料的性能、骨料颜色及路面龄期密切相关;热反射涂层在颜料中添加高折光率材料,通过反射太阳辐射降低路面对太阳辐射的吸收量,从而降低路面热量的积累,颜色越浅反射效果越明显,考虑路面低温对冬季路用性能的不利影响,在路面材料中添加可逆热变色微胶囊,考虑其经济性及光稳定性并未广泛应用;由于水分子对太阳辐射的吸收程度不同,随着面层材料含水量的增加,太阳反射率呈降低趋势,但可为蒸发散热提供源动力;根据城市构造分析,高宽比小于1的峡谷降温效果较好。虽然该5种因素对反射率的影响程度不同,但都不同程度地达到路面降温效果。同时,针对路面反射率现阶段研究的工程应用进行了阐述。更多还原

【Abstract】 Conventional pavements have large thermal inertia and strong capacity of heat absorption and heat storage, contributing to the development of urban heat island. In recent years, the researches on mitigating urban heat island effect by using cool pavement technologies are increasing. Based on the cool pavement technologies of pavement reflectance, the cooling mechanism of reflective pavement and its influence on outdoor thermal environment are analysed. The influences of 5 factors such as solar thermal radiation peak, surface layer material, thermal reflective coating, water content of pavement material and urban structure on pavement temperature are analysed. The result shows that(1) The peak value of solar radiation changes regularly with the seasons. Due to the different effects of peaks on the daily highest temperature, the pavement cooling effect of summer is obviously better than that of winter, which not only satisfies the summer cooling but also reduces the adverse effect on the winter pavement.(2) The effect of the surface layer material on the pavement temperature is closely related to the performance of the material, the color of the aggregate and the age of the pavement.(3) The heat reflective coating adds a high refractive index material to the pigment, and reduces the pavement’s absorption of solar radiation by reflective solar radiation, thereby reduces the accumulation of heat on the road surface. The lighter the color, the more obvious the reflection effect. Considering the adverse influence of pavement low temperature on the road performance in winter, the reversible thermochromic microcapsules are added to the pavement material, which is not widely used due to its economics and photostability.(4) Due to the different absorptions of solar radiation by water molecules, the solar reflectivity decreases with the increase of water content of the surface layer material, but it provides the source power for evaporation and heat dissipation.(5) According to urban structural analysis, the canyon cooling effect with aspect ratio less than 1 is better. Although these 5 factors have different influences on the pavement reflectance, all of them could achieve the cooling effect to a certain extent. Meanwhile, the engineering applications of researches on pavement reflectance at present stage are expounded.更多还原