Title: GGBS Cements Activated by Chloride:Hydration and Corrosion Potential
Author(s): Laurent Steger, Bernard Salesses, Cédric Patapy, Mohend Chaouche, Laurent Frouin, and Martin Cyr
Publication: Symposium Paper
Appears on pages(s): 49.1-49.18
Keywords: GGBS; activation; hydration; durability; corrosion; chloride
Ordinary portland cement (OPC) substitution by high contents of ground granulated blast furnace slags (GGBS) reduces the early hydration kinetics, causing a slower development of
mechanical properties. Chloride are well known for their accelerating effect on OPC but are mostly used for specific applications, such as non-reinforced concrete, due to their detrimental effects regarding steel bars corrosion. However, GGBS-based concretes are known for their ability to resist chloride ingress due to their capacity to fix more chlorides in hydrates, hence reducing the free chloride available for corrosion. This paper aims to present a link between strength development and in-situ formation of aluminate based hydrates at early age in the presence of chloride salts. Isothermal calorimetry is coupled with XRD investigations to gather insights on the accelerating mechanisms and on the potential impact of GGBS on durability. SEM-EDS observations were conducted to determine the spatial distribution of products formation and anhydrous grains dissolution in the presence of chlorides. The resistance to corrosion of chlorides/GGBS blends is then studied by electrochemical tests.