A three-phase model for concrete

摘要

Drying shrinkage of a concrete overlay influences the structural behaviour of a strengthened concrete structure. Hence, a three-phase model for concrete, based on the theory of porous media, is developed to simulate the change of moisture distribution and the resulting drying shrinkage in a realistic way. Because shrinkage strains start to develop after concrete setting, the hydration reaction, modelled by an evolution equation for the degree of hydration considering the influence of temperature and relative humidity must be taken into account. Comparisons of computed results from the numerical simulation of a brick-shaped concrete specimen strengthened by a concrete overlay with a thickness of 9 cm with test data, demonstrate the capabilities of the numerical model.