|Chloride ingress for concrete containing blast-furnace slag, related to microstructural parameters|
Gruyaert, E.; Van den Heede, P.; De Belie, N. (2009). Chloride ingress for concrete containing blast-furnace slag, related to microstructural parameters, in: Kovler, K. (Ed.) 2nd RILEM International Workshop on Concrete Durability and Service Life Planning - ConcreteLife'09. pp. 440-448
In: Kovler, K. (Ed.) (2009). 2nd RILEM International Workshop on Concrete Durability and Service Life Planning - ConcreteLife'09. RILEM publications: Bagneux. ISBN 978-2-35158-074-5. 626 pp., more
Chlorides which penetrate into reinforced concrete can deteriorate structures by corrosion. These chlorides can originate from seawater, de-icing salts or other chloride solutions. In this study, ordinary Portland cement (OPC) concrete and concrete in which 50%, 70% and 85% of the cement is replaced by BFS are compared at an age of 1, 3, 6 and 12 months with regard to chloride penetration. Therefore, non-steady state migration tests (CTH) were performed and the chloride penetration depth was determined by silver nitrate solution. In addition, rapid chloride tests (RCT) were used to give an indication of the total and free chloride content at different depths. The results indicate that concrete containing BFS is more resistant to chloride penetration in comparison to OPC concrete.To explain the different behaviour of concrete containing BFS in comparison to OPC concrete, the porosity of these mixtures was investigated. To determine the pore structure, vacuum absorption tests and capillary water sorption tests were performed. With increasing BFS content, the total porosity increases slightly, whereas the capillary porosity decreases, indicating a finer pore structure for BFS concrete. However, the capillary sorption in the zone surrounding a moulding surface is higher for concrete containing BFS, while the interior zone gives comparable results for OPC and BFS concrete.