Structural concrete at high temperature: carbonization, decarbonization and recarbonization

Abstract

The multichemophysical model of the processes of carbonization, decarbonization and recarbonization of concrete at high temperatures is analyzed. Experimental validation of the integrated model is carried out using thermogravimetric tests of cement stone and the strength of mortar composites immediately after high-temperature heating and after fire curing. CO2 concentration and humidity are experimentally varied as thermodynamic boundary conditions for wide range testing and validation. Compressive strength is not considered as a property of the material, but as a calculated structural characteristic of a cylindrical solid, where temperature, degree of hydration and carbonization develop unevenly. The developed model makes it possible to study wet, fire-damaged concrete as a composite multiscale material.