Measuring, modelling and 3D stress calculations of concrete in the early age. Compilation of Four Papers

The driving forces to cracking in concrete at early ages may be divided into 3 classes: 1 Self-induced deformations resulting from the cement/additions - hydration (autogenous shrinkage or swelling) 2 Thermally induced deformations and 3 Deformations resulting from moisture exchange with the environment Each of these deformations change character and magnitude as the concrete progresses through the 3 stages after mixing: liquid (or plastic for lower slump), semi-liquid (or semi-plastic) and finally solid. IPACS and all existing calculation programs focus on cracking risk in the early part of the solid stage (i.e. days after setting), and do not consider deformations caused by moisture exchange with the environment. The present collection of 4 papers, published in 2001, covers an overview of the knowledge on the field (paper 1), discusses possibilities and limitations regarding testing and modeling of thermal- and autogenous deformation (paper 2) and shows a full demonstration of a crack risk evaluation using 3D stress calculations for concretes with variable silica fume content (paper 3). The last paper (paper 4) discusses aspects of measuring technique and possible pitfalls when measuring autogenous deformation - an area which has shown to be very important when testing concrete in the early age.