CONSTRUCTABILITY STUDY OF ASPHALT PAVEMENTS INCORPORATING SHALLOW GEOTHERMAL ENERGY

Abstract

The incorporation of geothermal energy in heating and electricity production has rapidly increased during the last three decades. This paper focuses on the use of shallow geothermal energy in asphalt pavement, herein called Ground Coupled Hydronic Asphalt Pavement (GCHAP) system. GCHAP consists of a series of pipes embedded within the asphalt layer coupled with another network of pipes embedded in the soil. A circulating fluid acts to exchange the heat energy between the soil and the asphalt layer. The system can be used for cooling the pavement, which results in decreasing permanent deformation in the summer. This paper presents a study on the constructability and performance of such systems on a large-scale section. Numerical analyses and a pilot study were conducted to select the system design components. A 9.6 x 4 meter GCHAP section was constructed on a municipal road in addition to another control section. The secondary network of pipes was placed three meters below the ground. Sensors were embedded within the GCHAP system to record and compare the temperature of the pavement to that of the control section. The results showed that GCHAP section can decrease the pavement temperature leading to an increase in resistance to permanent deformation. Moreover, the constructability study showed the importance of performing a pilot study before constructing the system to ensure the resilience of the pipes.