Thermal Path Reconstruction for Reinforced Concrete Under Fire

Abstract

In post-fire investigation, the damage of fire-exposed concrete is usually related to the temperature time-history.This paper presents the results of an experimental investigation on reinforced concrete, cement pastes and mortars exposed to fire, aimed at identifying the benchmarks necessary to reconstruct the thermal path 15 dry core samples were obtained from a real fire damaged structure and compared to other reference dry cores collected in not damaged zones of the same structure. In addition, 16 irregular spalling samples were collected and investigated. In order to assess changes in mineralogical composition and microstructure modifications due to temperature, 20 cubic cement pastes samples and 20 prismatic mortars specimens were realized and exposed to temperature ranging from 200 • C up to 800 • C with a gradient of 10 • C/min and keeping the maximum temperature for 1h.Optical and Scanning Electron Microscopy, X-Ray Diffraction, Thermoanalysis and MIP porosimetry along with Helium picnometry allowed to investigate the damage degree and the mineralogical changes of the concrete and other cement based materials. Calibrated Colorimetry could determine fire temperature in the different parts of the samples due to colour changes in the mineralogical phases and in the microstructure of cement materials.

Buckling of Radially Loaded Concrete Cylinders in Fire Condition

“…Both transient thermal and structural analyses have been accomplished using solid elements as shown in Figure 6. Solid elements have been meshed in a hex dominant form as shown in Figure 7 [9][10][11][12][13][14][15][16][17][18][19]. The finite element analysis has been performed on three stages as shown in Figure 8.…”

Structural Behaviour of Steel Storage Racks Under Different Fire Scenarios

“…Fire effects on steel structures can be very dangerous: the variations of mechanical properties due to temperature variations can strongly reduce the bearing capacity and the induced thermal deformation can affect the global structural behavior [8]. For this reason, in case of fire, both mechanical and geometrical non linearities should be taken into account.…”

Modeling Temperature of Fire-Damaged Reinforced Concrete Buildings Based on Nondestructive Testing and Gene Algorithm Techniques

“…There is the propagation of cracks and surface delamination. Interestingly, due to the low thermal conductivity of concrete, it is structurally stable after exposure to fire up to 1000 °C [2,3]. However, at extremely higher temperatures, concrete is known to be in an unserviceable state, with evident damages, such as exposure of embedded reinforcing steel or total failure of the building.…”