Preparation And Study Of Fire-Resistant Performance Of A Novel Intumescent Fire Retardant Conting For Concrete

During the rapid development of modern construction, concrete reinforced with steel bars are using as building structures widely. Although the reinforced concrete structures or members are non-flammable, the fire insulation is so poor that, in the case of high temperature, the strength and stiffness of the reinforced concrete structures or elements decreases rapidly with concrete perhaps even bursting. In order to improve the fire resistance of reinforced concrete structure, it is necessary to prevent the heat transferring to the reinforced concrete structure from the outside. Currently the measures to improve fire resistance of reinforced concrete performance are placing additional expense of concrete protective layer covering the reinforced concrete structures or elements, or pasting fire board on the surface of reinforced concrete structures or elements, or installing sprinkler systems, special fire retardant paint spraying concrete, etc. The studies of many scholars show that fire-resistant coating is the best choice to improve the fire resistance of reinforced concrete structures or members with taking the performance, cost, construction and other comprehensive performance into account.Fire-resistant coating for concrete is a specifically designed coating to improve the fire resistance of concrete structures or components intended for mechanical properties significantly decreased of concrete structures under high temperature, which likely led to loss of structural stability collapse situations. It is usually constituted of film-forming substances, flame retardants and fillers. Now widely used fire retardant coating has disadvantages of poor adhesion, volatilization of a large number of toxic and harmful organic solvents, and toxic gas released when it caught by the fire.In order to avoid the drawbacks of the widely used fire retardant coating we mentioned, and improve the Adhesion and environmental nature, the thesis uses the epoxy as one of the membrane material, physical expansion type of expandable graphite as a flame retardant. First define coating formula through construction performance exploration and the main physical and chemical properties, then study the influence of different recruitment of membrane material epoxy resin and flame retardant expandable graphite in the fire protection coating construction performance and the fire protection performance, and finally prepare a good performance novel intumescent fire retardant coating for concrete, and has studied the protective function of different thicknesses of this fire protection coating to the concretes fire protection heat insulation.The result indicated the membrane material epoxy resin amount used 30% to 40%, as well as flame retardant expandable graphite amount used 10% to 30%, this fire protection coating has the good coating construction performance; when both the membrane material epoxy resin amount and flame retardant expandable graphite amount used 30%, the coating fire protection performance the best, its fire resistance rating through the tunnel test method and the cab test method achieve first-level; all the different thickness's fire protection coating can play a good heat insulation protective function to the concretes, especially when both the membrane material epoxy resin amount and flame retardant expandable graphite amount used 30%, and the spreading ratio is 1000 g/m2, this fire protection coating achieves the extremely good fire protection heat insulation protective function, for example, put iron parent metal with this fire protection coating under the flame high temperature, His/her the back fire surface temperature is slow along with the time variation rise, and maximum temperature only rise to 330℃.The concrete with no fire retardant coating compressive strength is 10.79Mpa,and the concrete with fire retardant coating compressive strength is 21.581Mpa,so this new-style intumescenting coating of concrete had good fire protection for concrete.