The Alkali-Silica Reaction (ASR) is a chemical reaction which causes expansions and unexpected deformations of concrete structures. A methodology of assessment of ASRdamaged structures is required in order to evaluate their structural stability. Chemomechanical calculations have been performed in order to investigate the assumption of modeling ASR-induced expansions as imposed strains. The input data for the model comprises of the moisture distribution in the damaged structures, ASR-induced potential strains and the influence of ASR on the concrete mechanical properties. The results of calculations have been compared with the experimental data obtained from ASR-damaged beam specimens. The role of water supply and reinforcement have been analyzed in comparing the deformations of plain and reinforced concrete beams subjected to a moisture gradient. Calculations show that cracking and compressive stresses (here induced by steel reinforcement) have a large influence on the anisotropy of the ASR-swellings. This induced anisotropy is shown to be one of the main factors which should be considered while predicting the mechanical behavior of ASR-damaged structures.

SUMMARYThe general framework of the paper deals with the "nite element modelling of thermomechanical problems involving viscous materials. The study focuses on the statement of constitutive equations describing the thermoviscoplastic behaviour of bituminous concrete, as well as on their implementation in a "nite element program. After stating the general equations of the space-and time-continuous problem and the constitutive relations governing the viscoplastic component of the bituminous concrete behaviour, we deal with their integration over "nite time steps, considering two di!erent schemes. Eventually, two sets of numerical results are presented. The "rst one, an homogeneous triaxial test, is used to compare those schemes, whereas the second one consists of numerical simulations of real-size experiments performed on a road structure subjected to thermal and mechanical loadings. By comparing the numerical results with experimental ones, it allows us to test the "nite element code on a more complex and realistic problem.

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