Influence of cyclic frost deterioration on water sorptivity of microcracked cementitious composites

Engineered cementitious composites (ECCs) are relatively new construction materials characterized by strain-hardening behavior under excessive tensile loading. Unlike conventional concrete materials, which generally show failure after first tensile cracking, ECCs strainharden upon excessive loading by creating multiple closely-spaced microcracks. Given the fact that crack widths in ECCs are at micron levels, water movement into these cracks through capillary suction requires further attention, especially under frost action. This paper therefore explores the effectiveness of frost action on water movement into microcracked ECCs. The experimental study covered the sorptivity measurements of ECC mixtures produced with mineral admixtures with different chemical compositions after exposure to cyclic freezing and thawing (F=T), in accordance with ASTM C 666, Procedure A. Air-void characteristics of ECCs were also compared. Experimental findings showed that air-void parameters are not the sole influential parameters on the durability of microcracked ECCs under frost deterioration. Instead of being negatively influenced by the severe conditioning under frost action until the end of 150 F=T cycles, sorptivity measurements of ECCs went down owing to self-healing in microcracks, depending on mixture composition. However, after 150 F=T cycles, deterioration surpassed the self-healing effect and increased sorptivity measurements.