Reduction mechanisms of static compressive strength in concrete due to permeation of liquids

Reduction mechanisms of the static compressive strengths in concrete due to liquid permeation are studied. The consumed energies under static compression are taken into account in failure process. The “crack-nucleation energy,” which increases exponentially as the strain increases, decreases with the increase in either the moisture content or the surface tension of permeating liquid. It is clarified that the decrease in the compressive strength of concrete due to permeation of liquids results from the reduction in the surface energy associated with the nucleation of internal micro-cracks.

► Micro-cracking process of concrete under uniaxial compression is studied.
► Energies during compression are calculated from loading/unloading curves.
► Crack-nucleation energy increases exponentially as the strain increases.
► The energy decreases with moisture content or surface tension of liquid.
► Liquid permeation reduces energy to nucleate cracks and strength decrease follows.