ABSTRACT
First comment: We propose to call all external volume changes, taking place without any mass change as autogenous deformation. The autogenous deformation is of course mainly caused by the chemical shrinkage, which is fundamental. However, it is also influenced by possible re-absorption of bleed water and water absorbed in the aggregate which may reduce the autogenous shrinkage and even turn it into swelling. Autogenous deformation may be measured both volumetric and linear. The second comment is that one should distinguish between the fundamental point of view and design point of view. From the design point of view, we suggest that we should distinguish between the plastic phase, or what we call the initial phase, in which we have typical cracks due to plastic shrinkage, and the thermal phase or hardening phase. In the thermal phase autogenous deformation will generate stresses that can be taken into account during design. These two phases should be considered separately and when we should use different kinds of test methods. In your suggestion this deviation point was around the time of initial setting. And then we may run into some problems; how do we define the initial setting and how do we test and confirm initial setting which is very consistency dependent, etc.
