Comportamento residual do concreto leve não estrutural com pérolas de EPS após exposição a altas temperaturas e resfriamento rápido

Abstract

The design of lightweight concrete with expanded polystyrene (EPS) came about with the development of concrete technology and the constant concern with the issue of sustainability. However, in order for the advantages of lightweight concrete to be exploited, it is necessary, for safety reasons, to study its performance in the most varied situations in which it can be subjected. Knowledge of the residual behavior of non-structural lightweight concrete with expanded polystyrene (EPS) beads after a fire and rapid cooling situation is of fundamental importance, in order to reduce the harmful effects caused by fires, since concrete structures are eventually exposed to fire situations controlled by rapid cooling with water. Therefore, this work aims to analyze the residual behavior of lightweight concrete with EPS beads after being subjected to high temperatures and rapid cooling. For this, the specimens were subjected to heating via oven and gasoline that obeys the standard fire curve to certain predefined levels, and then they were subjected to rapid cooling and hydration for 7, 14, 21 and 28 days. The determination of the mechanical properties occurred through the tests of Normal Compression and Diametral Compression. The results obtained show gains in compressive strength after periods of hydration of the samples heated in the oven and gasoline. During the warming, no explosive detachment was verified in any of the specimens. It is believed that the amount of pores in the matrix allowed the migration of steam to the surface with relative ease, and that the fact that the samples have low humidity due to the curing time in the open air reduced the possibility of spalling. However, the tensile strength of specimens without and with hydration does not follow a theoretical pattern of total gain or loss over the days. The specific mass of materials burned in gasoline and oven were lower compared to unburned material. The results of this work reinforce the importance of studying the behavior of concrete in the face of high temperatures from a fire. In addition to indicating that the rehydration of the concrete after heating can contribute to the recovery of the part of the initial mechanical strength.