Evaluation of the effects of drying shrinkage on the behavior of concrete structures strengthened by overlays

The present contribution focuses on the experimental evaluation of the effects of drying shrinkage on the behavior of concrete structures strengthened by overlays. To this end a comprehensive laboratory test program is presented. Tests on thin concrete slices served for determining the water desorption isotherm and the ultimate drying shrinkage strains. The time and depth dependent mass water content distributions and the evolution of the drying shrinkage strains were measured on concrete prisms and on larger brick-shaped concrete specimens during two years of drying. After two years of drying the brick-shaped specimens were supplemented by a concrete overlay. Measurements of the mass water content distribution were continued during water jetting and subsequent wetting of the top surface. In addition, the shrinkage strains were recorded in the composite specimens during subsequent drying.