沥青路面用复合定形相变材料调温效果研究

Study on Temperature Control Performance of Composite Shaped Phase Change Material for Asphalt Pavement

借助微胶囊法制备十四烷为相变材料的复合定形相变材料,采用DSC测试复合定形相变材料老化前后的热物性参数,通过直掺法制备调温沥青混合料,并采用调温试验测定不同配方、不同掺量复合定形相变材料的调温效果。结果表明:老化后,复合定形相变材料的相变起始温度与相变焓值均有一定程度的降低:相变材料100%为十四烷的复合定形相变材料在升降温阶段的相变起始温度分别降低了20. 3%、14. 3%,其相变焓值分别降低了13. 1%、12. 8%;相变材料由77. 84%十四烷与22. 16%液体石蜡组成的复合定形相变材料在升降温阶段的相变起始温度分别降低了38. 5%、15. 3%,其相变焓值分别降低了11. 4%、13. 3%。建议在沥青混合料配料计算过程中,考虑复合定形相变材料在老化过程中的质量损失率,以确保吸放热量保持稳定。相变材料为100%的十四烷的复合定形相变材料在升降温阶段的调温效果均为最优:在降温阶段,其掺量为0. 5%时的调温效果最优,在升温阶段,其掺量为0. 3%时的调温效果最优,建议针对复合定形相变材料在沥青混合料中的不同作用选取合理而高效的掺量。相变材料发挥的调温效果与相变起始温度与相变材料的含量密切相关。

The composite shaped phase change material(CSPCM)was prepared by microcapsule method.The phase change material was Tetradecane.The thermal properties of the CSPCM before and after aging were measured by DSC,the tempered asphalt mixture was prepared by direct addition method,and finally the thermostat effect of CSPCM with different formulation and content were tested by the thermostat test.The result shows that the initial phase change temperature and phase change enthalpy of aged CSPCM decrease:the initial phase change temperature of the CSPCM with 100%tetradecane is reduced by 20.3%(heating stage)and 14.3%(cooling stage)respectively,the corresponding phase change enthalpy is reduced by 13.1%(heating stage)and 12.8%(cooling stage)respectively;the initial phase change temperature of the CSPCM consists of 77.84%tetradecane and 22.16%liquid paraffin is reduced by 38.5%(heating stage)and 15.3%(cooling stage)respectively,the corresponding phase change enthalpy is reduced by 11.4%(heating stage)and 13.3%(cooling stage)respectively.It is suggested that the mass loss rate of CSPCM during aging process should be considered,which is good for ensuring the stability of absorption heat.During the heating/cooling stage,the CSPCM with 100%tetradecane has the best effect of adjusting temperature:the best adjusting temperature effect of CSPCM with 100%tetradecane is 0.5%content at the cooling stage and 0.3%content at the heating stage,it is suggested to select a reasonable and efficient content for the different functions of CSPCM with 100%tetradecane in asphalt mixture.The initial phase change temperature and phase change material content have a significant effect on the tempering of CSPCM.