Mechanical Behaviour of Concrete under Physical-Chemical Attacks

The analysis of the evolution of stress-strain states into reinforced concrete structures due to humidity and temperature changes and physical-chemical attacks by pollutant species is presented. Humidity and temperature affect both the process of cement hydration and the progress of shrinkage and creep, while thermal transients cause spatial variable thermal deformations. Moreover aggressive species, which penetrate from the external environment into concrete via diffusive processes, might lead both to the reinforcement corrosion (i.e. carbonation phenomena and chlorides) and to the concrete damage producing expansive phenomena (i.e. sulphates and calcium chloride). Within the framework of a finite element approach, the solution of the mechanical equilibrium of the elastic-damage continua, coupled with the diffusion processes of humidity, temperature and chemical species, is carried out. Some examples are shown in order to demonstrate the reliability of the proposed approach in practical engineering problems.