Durability of concrete and cement composites

Modelling chemical attack

Modelling the chemical degradation of concrete is complex because of the numerous chemical reactions and variety of conditions potentially involved. Models have been developed for leaching of Ca2+ ions by water (Bentz and Garboczi, 1992; Delagrave et al., 1997), external sulfate attack/decalcification (Marchand et al., 1999; Maltais et al., 2004) or attack by one type of acid, e.g. carbonic acid (Grube and Rechenberg, 1989), but can only apply to a limited set of conditions. Development of realistic models is an ongoing problem (Beddoe and Dorner, 2005). Much work is being carried out to produce computer-based models of the behaviour of cement products used in stabilisation and solid- ification of hazardous wastes, in particular radioactive material. The lifetimes expected of these cement-based materials are much greater than those in other structures and so computer-modelling combined with carefully designed experimental work will be necessary for predicting performance (see, e.g., Adenot and Richet, 1997; Matte et al., 2000, Yokozeki et al., 2004).

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