Functional composite phase change materials (CPCMs) are particularly emphasized by integrating PCM particles in building materials for energy-saving applications, due to PCM's excellent temperature adjustment capacity. However, the inherent drawback of low thermal conductivity of PCM decreases its phase-changing efficiency. Finding highly-efficient heat transfer technique becomes quite necessary. This work utilizes small hollow steel balls (HSBs) to encapsulate paraffin to provide a simple and practical solution, not only ensuring sufficient protection to PCM core in alkaline environment but also enhancing heat transfer into PCM. Then the PCM-HSBs aggregates mix with cementitious matrix to fabricate CPCM. The composite thermal conductivity (CTC) is respectively determined by experiment, theory and computational microstructure model precisely representing random morphology of PCM-HSBs in matrix, and a good agreement is observed between them. Then the dependence of CTC on microstructure features is illustrated to identify their roles. Finally, the composite compressive strength (CCS) and failure mode is discussed briefly to establish comprehensive understanding of composite properties. The results show that CTC has a significant increase of 25.84%, while CCS decreases 12.7%, when 15.28% PCM-HSBs are used. The degradation of CCS is mainly attributed to the smooth surface of HSB, which can be roughened by abrasive blasting.

由于 PCM 具有出色的温度调节能力，功能性复合相变材料 (CPCM) 通过将 PCM 颗粒集成到节能应用的建筑材料中而受到特别重视。然而，PCM导热系数低的固有缺点降低了其相变效率。寻找高效的传热技术变得十分必要。这项工作利用小型空心钢球 (HSB) 封装石蜡，提供了一种简单实用的解决方案，不仅可以确保在碱性环境中对 PCM 核心提供足够的保护，还可以增强向 PCM 的热传递。然后将 PCM-HSBs 骨料与水泥基体混合以制备 CPCM。复合热导率（CTC）分别由实验确定，理论和计算微观结构模型精确地表示了基体中PCM-HSBs的随机形态，并且它们之间观察到了良好的一致性。然后说明 CTC 对微观结构特征的依赖性以确定它们的作用。最后，简要讨论了复合材料的抗压强度 (CCS) 和失效模式，以建立对复合材料性能的全面了解。结果表明，当使用 15.28% 的 PCM-HSB 时，CTC 显着增加了 25.84%，而 CCS 减少了 12.7%。CCS的降解主要归因于HSB的光滑表面，可以通过喷砂将其粗糙化。简要讨论了复合材料的抗压强度 (CCS) 和失效模式，以建立对复合材料性能的全面了解。结果表明，当使用 15.28% 的 PCM-HSB 时，CTC 显着增加了 25.84%，而 CCS 减少了 12.7%。CCS的降解主要归因于HSB的光滑表面，可以通过喷砂将其粗糙化。简要讨论了复合材料的抗压强度 (CCS) 和失效模式，以建立对复合材料性能的全面了解。结果表明，当使用 15.28% 的 PCM-HSB 时，CTC 显着增加了 25.84%，而 CCS 减少了 12.7%。CCS的降解主要归因于HSB的光滑表面，可以通过喷砂将其粗糙化。