Protective or damage promoting effect of calcium carbonate layers on the surface of cement based materials in aqueous environments

Thus, investigations of the structural and chemical properties of the material/water interface were carried out in laboratory experiments and case studies to elucidate the consequences of surface reactions for the durability of cement based materials exposed to tap water. Focused Ion Beam investigations revealed that a protective effect of a CaCO3 covering layer depends on its structural properties, which are in turn affected by the hydro-chemical conditions during crystallization. Surface precipitation of CaCO3 can trigger further chemical degradation, if the required calcium is supplied by the pore solution of the material.