Sustainable performance of alkali-activated blast furnace cement concrete with high freeze-thaw resistance

Abstract

The application of blast furnace cements with minor clinker constituent is an actual task due to their conformity with modern tendencies of sustainable development. The alkali metal compounds were proposed to increase activity of CEM III/C. The aim of the research was to investigate the effects of technological factors on porous structure of alkali-activated blast furnace cement concrete (further, AABFC concrete) to ensure its sustainable performance by criterium of freeze-thaw resistance in NaCl solution. The effects of fresh concrete consistency, aggregate state of alkaline component and curing conditions on sustainability of AABFC concrete were investigated. Increasing of fresh concrete consistency from class S1 up to class S4 due to chemical plasticization as well as application of alkaline component in dry form, in contrast to liquid form, ensures negative changes in porous structure of AABFC concrete. These changes cause decreasing of freeze-thaw resistance from mark F500 down to F200. It was revealed that hardening of plasticized AABFC concrete under normal conditions (t = 20±2 ° C, RH = 95±5%), compared with hardening in water or under steam curing (t = 85±5 ° C), ensures more effective porous structure which causes maintained freeze-thaw resistance of F300 in contrast to F200 and F250 agreeable.