This paper investigates the potential of harvesting heat energy from geothermal pavements constructed with construction and demolition (C&D) waste materials, by using experimental and numerical methods. The deformation, stiffness, and shear strength properties of two types of C&D materials used for the construction of geothermal pavements, namely crushed brick (CB) and recycled concrete aggregate (RCA), were evaluated by performing repeated load triaxial (RLT) and quick shear tests. A multistage RLT test was adopted to investigate the deformation behavior of CB and RCA over a wide range of stress levels. The stiffness of materials was evaluated in different stress combinations. A small-scale prototype pavement system with a serpentine-shaped copper pipe was placed in the C&D base layer for evaluating the potential of heat energy extraction. Comparisons were made between the performance of CB and RCA for construction of geothermal pavements. RCA was found to be considerably superior to CB in terms of strength and deformation properties. On the other hand, the geothermal pavement constructed with CB was found to have slightly more favorable thermal performance due to the higher thermal conductivity of CB compared to RCA. A numerical model was developed and validated based on the experimental results to investigate the effect of design parameters on the thermal performance of the geothermal pavements. The effect of base layer thermal conductivity, Reynolds number, solar irradiance, inlet water temperature, and pipe embedment depth, was investigated on the surface temperature reduction and heat gain of the system. Overall, the construction of geothermal pavement with C&D materials was found to be a feasible approach which further enhances the environmental sustainability of the system.

本文通过实验和数值方法研究了从用建筑和拆除 (C&D) 废料建造的地热路面收集热能的潜力。通过重复加载三轴（RLT）和快速剪切，评估了两种用于建造地热路面的拆建材料，即碎砖（CB）和再生混凝土骨料（RCA）的变形、刚度和剪切强度性能。测试。采用多级 RLT 测试来研究 CB 和 RCA 在广泛的应力水平范围内的变形行为。在不同的应力组合下评估材料的刚度。一个带有蛇形铜管的小型原型路面系统被放置在 C& D 基础层，用于评估热能提取的潜力。对CB和RCA在地热路面施工中的性能进行了比较。发现 RCA 在强度和变形性能方面明显优于 CB。另一方面，由于与 RCA 相比，CB 的热导率更高，因此发现用 CB 构建的地热路面具有稍微更有利的热性能。基于实验结果开发并验证了数值模型，以研究设计参数对地热路面热性能的影响。研究了基层热导率、雷诺数、太阳辐照度、进水温度和管道埋置深度对系统表面温度降低和热增益的影响。