Assessment of the prediction methods of restrained strains and self-stresses of the members made of expansive concretes

Abstract

In various time periods, interest to RC structures made of expansive concretes was very different: from admiration after its successful utilization in the real practice of civil engineering works (for instance, jointless self-stressed and post-tensioned slab-on-ground with dimensions of 144x72 m2) to great criticism and sarcasm when shrinkage cracking appeared after full self-stressing loosing or even self-damaging taking place in case, when «unbalanced» expansion and strength developmentwere observed. Nevertheless, the interest to the elements made of self-stressing concrete drastically increased in the last decades. By the way, it is necessary to mention that in its majority, there are elements with so-called composite reinforcement (bars). In such a bars, the reinforcing fibers are made of glass, aramid, carbon and etc. However, prediction methods of the restrained strains and self-stresses development are not always characterized by the accuracy in connection with the self-prestressing is a multifactorial process and, thus, these methods need for clarification and modification in future. In this paper authors presented short historical review on expansive binders production for self-stressing and shrinkage-compensating concretes, discussed advantages and disadvantages of the known models for restrained strains and compressive stresses assessment as a resultof self-prestrssing, as well as some own results of the behavior of self-stressed concrete structural elements, reinforced with both steel and glass fibers reinforced polymer (GFRP) bars on the both expansion (self-prestressing) stage and under the static loading.