Damage evolution of blended cement concrete under sodium sulfate attack in relation to ITZ volume content

To understand the relation between the interfacial transition zone (ITZ) volume content and damage evolution of concrete under sodium sulfate attack, the development of length, mass and dynamic elastic modulus among specimens with varied aggregates was evaluated. After 12 months of exposure, there is a general trend toward increasing expansion, and reducing E-Rd with increasing ITZ volume content for reference and limestone filler blended binary groups. No sign of degradation has been observed in slag blended specimens during the testing age. Element mapping exhibits that the sulfur presented as the form of gypsum tends to locate in the ITZ preferentially. (C) 2018 Published by Elsevier Ltd.