MECHANICAL-BEHAVIOR 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 physic al-chemical attacks by pollutant species is presented. Humidity and te mperature affect both the process of cement hydration and the progress of shrinkage and creep, while thermal transients cause spatial variab le 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 phen omena and chlorides) and to the concrete damage producing expansive ph enomena (i.e., sulfates 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 e xamples are shown in order to demonstrate the reliability of the propo sed approach in practical engineering problems.