Prediction of mechanical properties and long-term deformation of concrete structures considering the moisture distribution

Abstract

Mechanical properties and long-term deformation are basic and important properties of concrete for the design and safety of concrete structures. Mechanical properties and long-term deformation are dependent on various factors and ambient temperature and humidity which are not able to control at the construction site are the major extrinsic factors. However, previous researches have usually focused on the temperature rather than the humidity because of the difficulties in experiments. Therefore, new prediction models for mechanical properties and long-term deformation by considering the history of pore humidity inside the concrete structures are suggested in this study. Pore humidity distribution is analyzed by the self-desiccation model and diffusion theory. Mechanical properties are predicted from the existing rate constant model and the relationship between the degree of hydration and pore humidity. Long-term deformation is analyzed from the variation of pore humidity with time and modified mechanical properties. New models are verified by comparing the experimental results in the literature. Typical concrete members, column, beam, wall and slab, are analyzed with the new models and the average properties are suggested as simple model equations and nomographs for practical use. Furthermore, new models are applied for the structural analysis and make the prediction of column shortening more reasonable. Suggested models are applicable for concrete under various climate at the construction sites.