Reformative Effects of Intumescent Coating on the Structural Characteristics of Cold-Formed Steel

Abstract

Intumescent fire-resistive coatings are a more recent type of passive fireproofing thin film that swells many times its initial applied thickness, generating an insulating char that functions as a thermal barrier between the fire and structural steel. It keeps the heat of steel members from reaching critical levels and aids in the structural integrity during a fire. They are architects and designers’ favorite choice for passive fire protection of load-bearing steel frame structures because of their aesthetic look, versatility, rapidity of application, and ease of inspection and maintenance. In this study, axial tensile, thermal conductivity, and hardness tests have been performed on S235 cold-formed steel specimens that were exposed to increasing temperature periods. The mechanical behavior of coated and uncoated specimens was investigated over the modulus of elasticity, yield strength/strain, and ultimate strength/strain values for all temperatures. As a result of the research, gradually increasing changes were observed in the mechanical properties of coated and uncoated specimens at increasing temperature levels, compared to each other. However, performance increment on the coated specimens was limited in terms of strength and strain characteristics than expected. Two essential reasons for this conclusion are that the specimens were exposed to heat for a long time after reaching the target temperature and also that the wall thickness of the specimens was thinner with respect to the usual application method of the protective coating. In order to examine the structural properties of the test specimens after elevated temperature effects, thermal conductivity measurement was also performed. Temperature difference between coated and uncoated surfaces provided a benefit in the range of 29–56% due to the coating. Lastly, microstructure imaging techniques demonstrated grain coarsening and no crack development with the increase in temperature.

Investigation of the Structural Behavior of Reinforced Concrete Beams at Elevated Temperatures

“…Considering previous studies, the ISO-834 standard fire effect was used as the heating regime. 14,15,18,19,31,34,35 Then, for the purpose of examining the effects of heating on the specimens, they were subjected to the loading.…”

“…The control specimens were tested at room temperature (23 °C) whereas others were exposed to the elevated temperatures and left to cooling. Considering previous studies, the ISO-834 standard fire effect was used as the heating regime. ,,,,,, Then, for the purpose of examining the effects of heating on the specimens, they were subjected to the loading.…”

Mechanical Properties of S235 Steel Protected with Intumescent Coatings Under High Temperatures: An Experimental Study

“…Despite the advances in fire-resistant materials, significant vulnerabilities still exist, particularly with cold-formed thin-walled steel profiles. These profiles, which are commonly used due to their cost-effectiveness and ease of installation, are less resistant to fire compared to their hot-rolled counterparts, a fact that has been well documented in various studies [1][2][3][4][5][6][7][8][9]. For instance, research has shown that a marked decrease in mechanical strength and stiffness occurs as temperatures rise, with critical degradation occurring between 550 and 600 • C [10][11][12][13][14][15].…”

“…After the fire incident at the American World Trade Center on September 11th, academics and structural engineers turned their attention to examining the behavior of steel during and after fires. They have carried out numerous studies to explore the behavior of steel exposed to fire [1][2][3][4][5][6][7][8][9]. Cold-formed steel profiles are less fire-resistant than hot-rolled profiles.…”

“…These coatings swell and form an insulating char layer, acting as a thin fire-resistant coating. This prevents the steel elements from reaching critical temperatures during a fire, thereby assisting in maintaining the structural integrity of the building [8]. Due to their aesthetic appearance, versatility, quick application, and ease of inspection and maintenance, passive fire protection for load-bearing steel frame structures is preferred by architects and designers.…”