路用相变材料研究现状和发展趋势

Research and Development Trend of Road Usage Phase Change Materials

相变材料(PCMs)作为调温材料出现在人们视野以来,其多样性及功能性不断发展,被广泛应用于建筑材料领域,调温和节能效果十分显著。PCMs具有智能性和自发性,能有效调节基体材料的温度范围,这一特点也适用于交通材料领域,用于道路的调温从而减少温度病害。此外,采用合适的PCMs还可赋予路面更多的功能性,如融雪、抵抗冻融循环及城市热岛效应等,十分契合我国智能交通、绿色交通的可持续发展理念。然而,PCMs在交通材料领域的研究尚不成熟,从路面应用形式到材料的选取等方面均存在诸多问题。PCMs种类繁多,根据相变形态分为固固和固液型两大类。固固型具有极高的相变温度,难以满足道路环境所需的温度需求,而固液型相变过程出现的液相形态和体积变化会破坏路面的结构,均难以满足相变路面关于调温效果和力学特性的要求。目前提出的解决方案引入了其他材料弥补的方式。具有较好前景的方案包括复合相变材料(CPCMs)、封装包覆、化学桥联、微胶囊等。其中CPCMs具有多样性,可根据需求选取合适的基体材料和固液型相变材料(SLPCMs),通过物理吸附将两者结合;封装包覆是在PCMs外侧形成包覆外壳防止液相PCMs流动并提供足够的力学性能,如溶胶-凝胶工艺;化学桥联通过分子桥加强了基体材料和PCMs之间的联系;而微胶囊类似于封装包覆的原理,但主要针对液相PCMs且具有较小的粒径,可减轻对路面的不利影响。此外,聚氨酯固固相变材料也具有较好的路面适用性,可通过调整化学反应对其相变特性进行调节。本文综述了路用相变材料的研究进展和发展趋势。首先明确了相变沥青路面的工作原理,确定了相变沥青路面系统的最佳应用形式,基于此提出了路用相变材料的技术要求;其次根据要求对纯相变材料进行筛选并分析了路用前景,引入复合相变材料(CPCMs)和微胶囊技术改善沥青路面中PCMs的工作环境,并对其路用适配性和应用前景进行评价;最后提出了相变自愈复合微胶囊的构想,丰富了智能路面的多样性,并对今后的发展进行了展望。

Since the phase change materials(PCMs)as building materials extensively,the diversity and function have been continuously developed,and the temperature regulation and energy saving is significant.PCMs are intelligent and spontaneous,and can effectively adjust temperature range of matrix materials,these characteristics are also applicable to the field of traffic materials,can be used for road temperature regulation to reduce temperature diseases.In addition,more road functionality adopted by using appropriate PCMs,such as snow melting,freeze-thaw resistance and reducing urban heat island effect,correspond to the sustainable development concept of intelligent transportation and green transportation in China.However,research of PCMs of traffic materials is not mature yet,including application form of pavement and the selection of materials.Various PCMs can be divided into solid-solid and solid-liquid types according to the phase change morphology.Further,the solid-solid type has a very high phase change temperature,is difficult to meet the temperature requirements of road environment,but the solid-liquid phase with transformation of liquid morphology and volume will damage pavement structure.None of them can meet the requirements of temperature regulation effect and mechanical characteristics of phase change pavement.At present,the proposed solution is in combination with other materials.The promising solutions include composite phase change materials(CPCMS),encapsulation,chemical bridging and microcapsule,etc.Physical adsorption can combine suitable matrix materials with solid-liquid phase change materials(SLPCMs)according to the demand.The encapsulation,such as sol-gel,form shell outside the PCMs to prevent flowability of liquid PCMs and provide enough mechanical properties.The chemical bridging reinforce relationship between matrix material and PCMs through molecular bridge.While the principle of microcapsules is similar to encapsulation,the difference of microcapsules is smaller particle size and SLPCMs as objects,microcapsules can reduce disadvantageous with road.In addition,polyurethane solid-solid phase change material(PUSSPCM)can regulate phase change characteristics by adjustment of chemical reaction,having better road applicability.This review mainly summarizes the research and development trend of phase change materials for road.The paper firstly exposes the working principle of phase change asphalt pavement,and then,the optimum application formation of phase change asphalt pavement system is determined and the technical requirements of road phase change materials are put forward.Additionally,pure phase change materials(PCMs)are screened and application prospects on road are analyzed.The composite phase change materials(CPCMs)and microcapsule technology to improve the working environment of PCMs are introduced in asphalt pavement,moreover,the adaptability and application prospects on road are evaluated.Finally,the conception of composite microcapsule with phase change and self-healing is addressed,and the diversity of intelligent pavement is enriched,as well as prospects for the future development of PCMs.