The main cause of premature deterioration of reinforced concrete structures is the corrosion of steel bars, induced by chloride ions (for example in marine environment) or by carbonation. At the same time, environmental-induced degradations of concrete can also affect the structure, such as external sulphate attack leading to the formation of ettringite, inducing expansion inside the materials and finally degradation. In this paper, concrete blocks (with supplementary cementitious materials), exposed to real environments, are studied and compared to laboratory experiments. Various aspects of the microstructure and of the pore structure are investigated, by using Mercury Intrusion Porosimetry and XRD, TGA, 27Al NMR, in order to better understand the results obtained relatively to the apparent chloride diffusion coefficients and to the chloride binding for example in marine environement. Results show the difference between the microstructures of the various materials and their consequences on the ingress of aggressive agents.