Properties of cement-based materials are governed by their nano-structure in general and by the interaction between the surfaces of the nano-particles with their hygral surrounding in particular. In this con- tribution local damage and nano-crack formation in the three-dimensional network…
Properties of cement-based materials are governed by their nano-structure in general and by the interaction between the surfaces of the nano-particles with their hygral surrounding in particular. In this con- tribution local damage and nano-crack formation in the three-dimensional network of nano-particles is con- sidered to be at the origin of crack formation. Macroscopic fracture energy can be considered to be the sum of a huge number of small energies consumed by nano-crack formation. Considering the physical process of nano-crack formation it is possible to predict the influence of variable environments on fracture energy. This hypothesis is verified by experimental investigations. The influence of aqueous NaCl solutions on strength, fracture energy and swelling has been determined. It is shown that values of fracture energy as determined in the laboratory are not conservative if applied for prediction of crack formation of reinforced concrete struc- tures situated in marine environment. This fact is of major importance for durability and service life of rein- forced concrete structures in marine environment.