Several investigations showed that blast furnace slag cement (BFSC) systems have less frost salt scaling (FSS) resistance in case of surface carbonation. A new hypothesis is introduced regarding the inferior FSS performance of carbonated BFSC systems. The hypothesis draws attention to the weakest link of all cementitious materials, the interfacial transition zone (ITZ). This zone is the transition phase between aggregate and cement paste in concrete or mortar while it is the zone between outer hydration products and unreacted clinker or pozzolanic particles in cement paste. Evidence was obtained that in BFSC paste, due to carbonation this zone becomes wider and weaker so at the end leads to an increased saturation rate and larger expansion pockets for freezing and eventual destruction. In this paper an initial attempt is presented on the modeling of FSS of carbonated BFSC paste according to the above-mentioned hypothesis. The model is based on the Delft Lattice Model and "Glue Spall" theory. Unreacted clinker particles, unreacted slag particles, pore structure, hydration products (matrix) and the interfacial zones are modelled at the micro level.
展开▼
