Abstract:

 In order to study the influence of expansive crystallized fireproof materials on the fire resistance of concrete, four kinds of crystallized fireproof coatings (1%,2%,3%,4%)were designed to improve the fire resistance of concrete. The mass, permeability and mechanical properties of concrete specimens were tested, and the microstructure was studied by SEM. The results showed that the combustion test caused serious damage to concrete, and the mass loss rate decreased first and then stabilized with the increase of the concentration of fire retardant coating. When the concentration of fire retardant coating is 0~3%, the seepage height of concrete decreases with the increase of concentration, and the variation range is small after more than 3%. The surface protection accelerates the formation of early strength of concrete, and the strength of concrete after 28 days of curing is almost not affected by the concentration of fire retardant coating. The pore structure of concrete surface was changed by crystalline fireproof coating, and the coating with 3% and 4% concentration forms a continuous crystal film structure.

Key words: crystalline fireproof material, fire resistance, concrete, surface protection