Kinetics of dolomite–portlandite reaction

The dedolomitization reaction kinetics are studied through several long-term experiments consisting of an aqueous dispersion of fine powders of dolomite and portlandite with different alkalinity, temperature and silica content. The experimental results are reproduced through computer simulation, which allows the estimation of the apparent dissolution constant rates for dolomite. These are discussed together with other parameters influencing the kinetics, in particular the modification of the specific surface of dolomite. The parameters obtained make it possible to predict the behavior of the system beyond experimental periods. Both experimental and simulated results are discussed in connection with the expansion and cracking occurrences observed in portland mortars and concretes made with dolomitic limestone.