The Effects Of Pipe For Exchanging Heat On Properties Of Conductive Asphalt Pavement For Solar Collecting

Embedding pipes into asphalt pavement can collect thermal energy by heat exchanging medium, which is meaningful to control service temperature and mitigate the nervous energy situation. Previous studies mainly focused on functional research and the material factors that affects the energy collecting performance. However, few investigations were conducted to study the effects of heat exchange pipes on asphalt mixture. Therefore, this paper studied the influence law of freeze-thaw cycles on the heat exchange pipes, asphalt concrete bonding performance. And also the effects of heat exchange pipes on asphalt concrete were studied. Finally, ways to improve bonding properties were investigated.Firstly, graphite was added to asphalt concrete to improve the conduction of asphalt solar collector. And the fixed pipes were used to compact embedded pipes asphalt concrete. The effects of freeze-thaw cycles on the heat exchange pipes and asphalt concrete bonding properties were investigated through the center pulling experiment. Results showed that bonding strength on the heat exchange pipes and asphalt concrete is related to effective bonding length. And the more numbers of freezing and thawing, the more decrement of the average bonding strength on the heat exchange pipes and asphalt concrete. The bonding strength between the heat transfer pipe and asphalt concrete has a piecewise linear relationship with the bonding length of pipe-concrete.Secondly, processing the surface with heat exchange pipes by emulsifying asphalt, epoxy and epoxy asphalt can improve the bonding performance of heat exchange pipes and asphalt concrete, and their bonding strengths increase 1.37, 1.31, 3.01 times respectively.Thirdly, wheel tracking tests and creep tests indicated that embedded pipes can improve high temperature property of asphalt concrete. And three point bending tests showed that the maximum bending tensile and strain cracking energy of buried pipes asphalt concrete at 0 oC can be greatly reduced to 42.84% and 31.5% respectively compared to asphalt mixture, however, the values were closed to it of asphalt concrete at-10 oC.Lastly, four point bending fatigue tests were applied to investigate influence of heat exchange pipes on asphalt concrete. The results indicated that the value of fatigue life remarkably reduced with heat exchange pipes embedding into asphalt concrete. And after processing on surface of heat exchange pipes, fatigue life was improved.