SIZE EFFECT ON THE ULTIMATE DRYING SHRINKAGE OF CONCRETE – MODELING WITH MICROPRESTRESS-SOLIDIFICATION THEORY
Drying shrinkage of concrete is a distinctively long-term process which is affected by many factors ranging from concrete composition, curing and ambient conditions to the dimensions and shape of the investigated structural member. In the case of standard-size structural members the ultimate value of drying shrinkage is reached within several decades, which hampers the experimental verification. In a reasonable time scope (e.g. 1 year) even the standard laboratory-size specimens provide only the initial evolution of shrinkage which cannot be extrapolated owing to the ill-posed nature of the problem. Furthermore, the experimental data indicate that there is a non-negligible size effect on the ultimate drying shrinkage which makes the transition from laboratory to structural size even more difficult. The objective of the current research is to assess this size effect from the perspective of the experimental data found in the literature, the design codes and prediction models for the long-term behavior of concrete, and finally, the coupled FEM simulations with the advanced constitutive model based on the Microprestress-Solidification theory.