Strength limit of concrete under repeated static loads

Abstract

In free (unconfined) concrete, until reaching the limit of long-term resistance during creep and the limit of strength during repeated loading, the generation and propagation of irreversible microcracks and ruptures is channeled, and only reversible microcracks are formed and propagated. After reaching the mentioned limits, reversible microcracks will definitely appear and grow into irreversible ones. Irreversible microcracks prevent quenching of creep deformation and lead to rupture. The formation and propagation of reversible and irreversible microcracks is not a cause at all, but rather a consequence of the creep of concrete caused by the water-splitting action within it. It is established that the growth of concrete flow deformation slows down exactly as during repeated stress, which does not exceed the strength limit.