Gas Retention Phenomenon in Dry or Partially-Saturated Concrete: Permeability Assessment

摘要

This study is an original contribution to the understanding of the hydraulic behaviour of cement-based materials when subjected to high temperatures. For two given concretes, gas permeability experiments have been conducted continuously, while heating a representative sample up to 200°C. Gas retention is evidenced, depending on the sample size (scale effect), water saturation level S,, and heating rate. Intrinsic permeability Kint and Klinkenberg coefficient fi are also evaluated at stabilized temperature levels of 60, 105 or 200°C. Complementarily to Mercury Intrusion Porosimetry (MIP) results, fi values support the interpretation of appreciable microstructure modifications due to heating. As a conclusion, observed phenomena at the laboratory scale testify of potentially strong gas retention effects upon engineering structures subjected to high temperature gradients.