Durability of Two Types of HPC at Sulphate Solution Environment

Abstract

Sulphate attack of concrete and cement composites comprises sulphate ions migration into the material porous space and their following reaction with hydration products in the presence of water. Newly formed compounds initiate filling of porous space and volume expansion. Sulphate corrosion phenomenon still belongs to the main mechanism affecting the durability and service life of concrete structures. This paper deals with the investigation of sulphate resistance of two types of High Performance Concrete (HPC) exposed for 168 days to sodium sulphate water solution and reference environment of distilled water. Corrosive action is monitored at chosen time periods non-destructively, i.e. using measurement of length and mass changes, basic physical characteristics and dynamic moduli. Additionally, destructive tests of mechanical parameters are realised. For samples immersed in distilled water, improvement in mechanical strength is observed for the both studied HPCs. In case of HPC C I containing crushed aggregate, the improvement of mechanical resistivity is observed for samples exposed to sulphate solution for 140 days only. For other researched period of sulphate exposure, mechanical strength decreased in comparison with the reference values. On the other hand, HPC C II exhibited mechanical resistivity to sulphate action in all examined time periods of sulphate solution exposure.