Materials (Sep 2022)

Heating Rate Effect on Gas Permeability and Pore Structure of Mortar under High Temperature

  • Wei Chen,
  • Yuehan Liu,
  • Mingquan Sheng,
  • Hejun Zhang,
  • Yue Liang,
  • Frederic Skoczylas

DOI
https://doi.org/10.3390/ma15196505
Journal volume & issue
Vol. 15, no. 19
p. 6505

Abstract

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This experimental study investigated the effect of heating rate on mortar gas permeability and microstructure. The mortar was heated to three target temperatures (400 °C, 500 °C, and 600 °C) at three heating rates (5 °C/min,10 °C/min, and 15 °C/min). The variations of gas permeability and porosity were measured simultaneously at different confining pressures, and the changes in mortar microstructure were analyzed by NMR and SEM techniques. The results show that the porosity and gas permeability increase with an increase in temperature and heating rate. The gas permeability and porosity continue to decrease as confinement is increased due to a reduction in the pore volume. The microstructure observed by SEM indicates that the high heating rate induces some microcracks at 500 °C and 600 °C. The fractal dimension based on NMR can quantitatively characterize the complexity of the mortar pore structure and shows a quadratic decreasing relationship with gas permeability and porosity.

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