Altered cement hydration and subsequently modified porosity, permeability and compressive strength of mortar specimens due to the influence of electrical current

摘要

This paper reports on the influence of stray current flow on microstructural properties, i.e. pore connectivity and permeability of mortar specimens, and link these to the observed alterations in mechanical properties and cement hydration. Mortar specimens were partly submerged in water and calcium hydroxide (Ca(OH)_2) as an external environment. The electrical current density applied was 10mA/m~2 as commonly used in cathodic protection (CP) applications. The results show that the stray current flowing through mortar specimens partly submerged in water tends to accelerate calcium ions leaching and results in increased porosity, permeability and decreased compressive strength. In contrast, a positive effect of the stray current flow was observed for mortar specimens, partly submerged in Ca(OH)_2 solution, where decreased porosity, permeability and increase in compressive strength were recorded. These observations are further discussed in terms of most plausible phenomena that link microstructural properties to mechanical and transport properties and related mechanisms.