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The goal of this study was to develop a prototype for harvesting thermoelectric energy from asphalt pavement roadways. This emerging research field encompasses technologies that capture the existing thermal energy in pavements to generate electricity without depleting natural resources. In lower latitudes, such as south Texas, the asphalt pavement surface temperature in the summer can reach 55°C because of solar radiation. Soil temperatures below the pavement, however, are roughly constant (i.e., 27°C to 33°C) at relatively shallow depths (150 mm). This thermal gradient between the surface temperature and the pavement substrata can be used to generate electrical power through thermoelectric generators (TEGs). The proposed prototype collects heat energy from the pavement surface and transfers the energy to a TEG embedded in the subgrade at the edge of the pavement shoulder. Evaluation of this prototype was carried out through finite element analysis, laboratory testing, and field experiments. The results suggest that the 64- × 64-mm TEG prototype can generate an average of 10 mW of electric power continuously over a period of 8 h in the weather conditions in south Texas. Scaling up this prototype by using multiple TEG units could generate sufficient electricity to sustainably power low-watt LED lights and roadway and traffic sensors in off-grid, remote areas.

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A three-dimensional (3-D) finite element (FE) model was developed to predict pavement responses to vehicular loading. The model incorporates measured tire-pavement contact stresses, continuous moving wheel loading, and hot-mix asphalt (HMA) viscoelastic characteristics. The model was fine-tuned using implicit-dynamic analysis and validated using pavement response from accelerated loading. Two tire configurations (dual-tire assembly and wide-base 455 tire) and three full-depth flexible pavement designs (HMA 152 mm, 254 mm, and 420 mm) were used in both FE modeling and accelerated loading tests. The predicted and calculated strain responses at the bottom of HMA were in agreement. Most important, the study shows that vertical shear strain in the upper 76 to 100 mm of the pavement surface is critical for thick pavement and is influenced by the 3-D tire-pavement contact stresses under each tire rib. However, the tensile strain at the bottom of HMA is affected mainly by the total wheel load. The vertical shear strain is responsible for near-surface fatigue cracking as well as HMA primary rutting. Top-down cracking could result from the local vertical shear strain in the upper 25 mm of the HMA where the effect of tire-pavement tangential stresses are the highest. In addition, the study concluded that wide-base tires cause higher longitudinal tensile strain at the bottom of HMA and compressive strain at the top of subgrade, where those responses are highly affected by the total wheel load. However, wide-base tires were found to cause less vertical shear strains near the surface than dual-tire assembly loading regardless of HMA thicknesses.