Long-term behavior of self-compacting and normal vibrated concrete: Experiments and code predictions

Abstract

The paper presents an experimental investigation that compares the long-term behavior (creep and shrinkage up to 680 days) of a Normal Vibrated Concrete (NVC) and a Self Compacting Concrete (SCC), with the latter being obtained by a slight change in mix-design (mainly an increase of the fly ash content to achieve self-compactability). It is shown that SCC exhibits higher shrinkage but the creep behavior is almost similar. As observed in other researches, this investigation confirms the influence of some parameters (i.e. cement content, water/cement ratio, type of filler) on the long-term behavior.The tests were conducted for a very long period (680 days) with respect to data usually available in literature and, for this reason, it was possible to measure the asymptotic values and compare them with the code predictions. This comparison showed the importance of the modulus of elasticity (experimentally detected and different from the code based value) to predict the service behavior of a reinforced concrete element.Most codes seem to underestimate the creep behavior of the SCC concrete mix, thus they cannot be applied directly and the MC2010 suggestion to consider higher (10–20%) long-term deformation for SCC powder type concrete seems to be reasonable, as well as the suggestion to perform tests on the material for structures sensitive to variations in creep/shrinkage (i.e. redundant structures).