The effects of post fire re-curing on mechanical properties and recovery of fiber reinforced concrete

Abstract

High temperatures or fire may cause significant damage in concrete. Moreover, further deterioration continues at the post heating stage. Although, there are few studies on the post fire rehabilitation of concrete in the literature, most of them focused only on the re-strengthening of concrete. On the other hand, the post fire activities in concrete have a significant impact on both mechanical and microstructural properties of concrete. Therefore, in this study new solution based re-curing techniques were utilized on the concrete specimens at the post heating stage. 7 days of post fire re-curing was applied in order to be more effective, practical and cost effective compared to the longer re-curing periods. At every stage of heating, cooling and re-curing; destructive and non-destructive tests were performed on cubic and prismatic specimens in order to determine the residual mechanical properties and to monitor the extent of recovery. Some of these specimens were also subjected to TGA analyses to better understand the microstructural changes of concrete following heating and the effect of re-curing methods. The results showed further deterioration in air re-cured concrete but recovery in water and solution based re-cured concrete.