In addition, the residual mechanical deformation at 600 ☌ was 50% for hot-rolled specimens and about 150% for cold-worked bars, which is important for the strength of the structure during a fire. However, at higher temperatures, a clear reduction in the mechanical strength of cold-worked reinforcement bars was observed, being up to 10–15% at 600 ☌. Comparing the thermal stability of both hot-rolled and cold-worked reinforcement bars, it was found that up to a temperature of 400 ☌, no significant changes in mechanical strength occur. Based on detailed studies, it was found that this effect occurs at temperatures above 400–500 ☌, depending on the type of steel. Steel can also exhibit a steel creep effect when the structure is exposed to the simultaneous effects of elevated temperature and high stresses. The reason for the loss of mechanical properties of steel at elevated temperatures may be stresses related to thermal expansion. Depending on the type of fire source and its intensity and the massiveness of the structural elements, the critical temperature of steel (450–550 ☌) can be reached within a few minutes. The result is deformation of the structural elements and their collapse. Under fire conditions, the temperature of steel structure elements rises very quickly, reaching the limit temperature in which a loss of mechanical properties occurs. One of the examples of demanding applications are steel and aluminum structures used in construction, which must be adequately protected against fire in order to maintain their load capacity for a specified period of time, enabling the evacuation and protection of the object. These compounds can be used to coat various materials, including building materials, ceramics, and construction elements. Silicone resins and branched polysiloxanes with very good thermal resistance are widely used as components of coating materials to meet the requirements of different applications. It has been demonstrated that silicate platelets are intercalated in the silicone matrix, significantly increasing its mechanical strength and resulting in high protection against fire. The most frequently used additives are expanded graphite and organoclay. The effect of silicone resin structure and the type of filler used in these paints on the properties of the char formed during the thermal decomposition of the intumescent paint will be discussed in detail. Some examples of innovative applications for fire protection of other materials will be also presented. The novel trends in application of silicone resins in intumescent paints used mostly for protection of steel structures against fire will be presented based on literature review. Moreover, this structure is stabilized by a chemical reaction between the hydroxyl groups from the organoclay and the silicone resin. The most important effect on the long-term heat resistance of the coating is connected with the type of resin. Silicone resins are widely applied as coating materials due to their unique properties, especially those related to very good heat resistance.
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