Effect of air voids on pavement thermal properties

To advance the study of pavement solar energy harvesting (PSEH), a study was made of the influence of moisture inside asphalt on its energy transport and storage abilities. Measurements of almost all the key thermal properties of asphalt are reported for a range of mixtures with various air void contents ranging from 4.5% to 30%. On the basis of this study it is concluded that, under dry conditions, asphalt mixtures with low air voids content have higher thermo-physical properties (i.e. density, thermal conductivity, specific heat capacity, thermal diffusivity and thermal effusivity) than asphalt mixtures with higher air voids content. Therefore, heating and cooling rates of dense asphalt mixtures were higher than those from porous asphalt mixtures. The total amount of energy accumulated in asphalt mixtures with different air voids content, but with the same constitutive materials, during heating and cooling depends only on the density of the mixtures. In addition, results indicate that asphalt mixtures with high air voids content accumulate less energy than asphalt mixtures with lower air voids content. It is concluded that mixtures with high air voids content are recommended to alleviate the urban heat island effect while mixtures with low air voids content are recommended for harvesting solar heat from pavements. The study also investigated the feasibility of harvesting heat from asphalt concrete mixtures by Thermoelectric Power Generators (TEG) and how the air voids content can affect the recovery of this heat. It is concluded that maintaining the temperature gradient between the asphalt pavement and the subgrade could provide a potential of converting heat energy to electrical energy through the use of Thermoelectric Power generators.

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Filing Info

  • Accession Number: 01660758
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Feb 20 2018 10:43AM