Influência do carregamento precoce em concretos de alta resistência

Abstract

This work presents an analysis of the axial compression behavior of a high strength concrete containing active silica, when subjected to a preload and two types of curing (submerged and thermal). In addition, the absorption of water by capillarity is evaluated in order to check the possibility of self-healing of microcracks after the pre-loading and curing process. The theme was chosen due to the need to reduce construction deadlines, since the market has been applying fast execution cycles and with this requesting the structure early, generating an increase in concerns regarding the deformations suffered and possible changes in the characteristics of the concrete. . For the research, a single line was used and a load was applied at 7 days. After loading, the specimens were divided, half of which were subjected to thermal curing and the other half to submerged curing, in order to assess the influence of the type of curing on its characteristics and on the recovery of damage caused by pre-loading. After 28 days of age, they were submitted to tests of resistance to compression and absorption by capillarity as an indicator of durability. The results showed that thermal curing is more effective than submerged curing, presenting better results both in reference specimens (without pre-loading) and in those subjected to early loading. Regarding the mechanical properties of concrete, the specimens subjected to preloading showed higher values for compressive strength and lower absorption rates, thus evidencing the possibility of self-healing of the micro-cracks caused by preloading for this type of concrete.