Experimental and theoretical studies of the construction and technical properties of fire-retardant vermiculite-concrete composites

Objective. Study of the dependence of the compressive strength on the average density and the flexural strength on the compressive strength of vermiculite concrete composite. Determination of the expression for the coefficients of thermal conductivity and heat capacity of the resulting vermiculite concrete composites in the developed software for thermal engineering calculation of the fire resistance limit of reinforced cement structures with a fire retardant layer of vermiculite concrete.

Method. Methods for reducing the consumption of cement binder in the developed fire-resistant concrete composites are considered. Experimental and theoretical methods for determining the fire-retardant properties of the developed vermiculite-concrete composites and expressions for determining their strength properties are proposed.

Result. The dependences of the ultimate compressive strength on the average density and the ultimate bending strength on the ultimate compressive strength of vermiculite concrete for the concretes under study, the dependence of the coefficients of thermal conductivity and heat capacity during a fire on the type and average density of vermiculite concrete composites were obtained.

Conclusion. Fiber-vermiculite-concrete composites with an average density of 470-560 kg/m3 have the best fire-retardant properties. Software has been developed for thermotechnical calculation using a numerical method of the fire resistance limit of two-layer reinforced-cement structures in a fire, ensuring at least 95% agreement with the experimental data of fire tests of two-layer reinforced-cement elements.

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