CFG能源桩用于混凝土路面除冰降温的试验研究

利用试验场足尺水泥粉煤灰碎石（CFG）能源桩，对模型混凝土路面冬季防冻除冰与夏季降温防护技术进行了试验研究，意在探索一种节能、环保、高效和经济的道路路面工程安全与耐久新技术。桩及模型混凝土板内均安装聚乙烯塑料管作为换热管，能源桩、混凝土板内安装有温度应变传感器测量换热过程中相应位置的温度、应变变化，混凝土板进出口水温、混凝土板表面温度分别由温度计、红外测温仪量测。试验主要分析冬季条件下，单根、双根能源桩供热一块混凝土板，以及在夏季条件下，单根能源桩降温一块混凝土板时，管路流体、混凝土板、桩的温度变化以及由温度引起的混凝土板、桩的应力应变变化。试验结果表明：冬季工况下，单根、双根能源桩可以使一块混凝土板表面温度保持在0℃以上，除冰效果显著；夏季工况下，单根能源桩对混凝土板降温，试验组与对照组混凝土板表面温差最大约为9.4℃，降温效果明显。能源桩和模型混凝土板在换热过程中，因温度改变会导致桩身和混凝土板中产生附加温度应力。桩身附加温度应力对桩结构完整性和安全性不会造成影响，而混凝土路面板的附加温度应力则总是与被加热或降温前的应力叠加使其总应力幅值降低，有利于混凝土路面板的安全性和耐久性。试验过程仅使用水泵为换热管中的流体提供动力进行循坏，不消耗其他任何形式能量，运营维护成本较低。

Experimental Study on CFG Energy Pile for Concrete Pavement Deicing and Cooling

This study was conducted to explore a new energy-saving, environment-friendly, highly efficient, and low-cost technique for increasing pavement safety and durability in the field of road engineering. It involved full-scale experiments on cementfly-ash gravel (CFG) piles that are used to deice a concrete pavement model to prevent frostbiting in winter, and cool the concrete pavement model, thereby preventing expansion, in summer. Polyethylene pipes were fixed in the piles and concrete pavement model; these pipes serve as heat exchange pipes. Thermal strain sensors were installed in the energy piles and concrete pavement model to monitor changes in temperature and strain during the heating-cooling process at corresponding positions. The temperature of the inlet/outlet water and surface of the concrete pavement model was measured using a thermometer and infrared thermometer, respectively. The experimental analyses focused primarily on the temperature change of water in the pipes, concrete pavement model, and piles, and the temperature-induced changes in stress/strain in the concrete pavement model and piles when the piles transfer heat to the concrete pavement model in winter or cool the concrete pavement model in summer. The experimental results indicate that:the piles, by transferring heat to the concrete pavement model in winter, are able to maintain the latter's surface temperature above 0℃, thus, proving the outstanding effects of deicing. In summer, the piles cool the concrete pavement model, and the maximum range of temperature difference is 9.4℃ between the experimental and control groups. During the heating or cooling process between the energy piles and concrete pavement model, the temperature change of the piles and concrete pavement model gives rise to additional thermal stresses. The additional thermal stress in the piles has no effect on their structural safety and integrity. The additional thermal stress in the concrete pavement model, superimposed on the stress before heating or cooling, always reduces the total stress, thereby increasing the safety and durability of the concrete pavement model. The power consumption in the heating or cooling system is dependent only on the use of a water pump. In the absence of any other source of energy consumption, the expenses due to operating and maintaining the system can be significantly low.