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).