Physicochemical Aspects of Natural and Forced Carbonization of Cement Systems.

The paper considers different aspects of natural and forced carbonization of binding agents and cement systems. It is shown that depending on the composition of binding agents, curing conditions, and transient factors, carbonization of hydrated cement can not only lead to corrosion and irreversible degradation, but also serve as a powerful productive endeavor for strengthening of concrete structures, self-healing of cracks in concrete, shrinkage reduction, and carbonization corrosion of constructional materials. Based on theoretical analysis of experimental data and the literature, a working hypothesis is developed concerning the observed processes of the structure formation based on the interaction of carbon dioxide and its derivatives with calcium aluminates and aluminate ferrites with the formation of hydrated calcium carboaluminates of various composition. Portlandite fixation is crucial for concrete structures capable of resisting to both carbon dioxide and sulfate corrosion and, sometimes, in introducing chemical additives, can lead to the structure strengthening. [ABSTRACT FROM AUTHOR]