COMPARATIVE ANALYSIS OF METHODS FOR DETERMINING THE EFFECTIVE CO2 DIFFUSION COEFFICIENT IN FINE-GRAINED CONCRETE OF DIFFERENT DENSITIES

Abstract

Direct and indirect methods for determining the effective diffusion coefficient of CO2 in concrete are considered. The features of the diffusion process in a capillary-porous body are described. Based on the test results of samples of fine-grained concrete with different densities, a comparative analysis of the coefficients obtained by the main methods was carried out. The criteria for comparison were the dependence of the water-cement ratio on diffusion, as well as the rate of carbonization on time. The presence of significant deviations in the low permeability concretes of the coefficients obtained by the membrane methods of 72 % and the electrical conductivity of concrete saturated with electrolyte 85 % in the low permeability concrete from the values obtained by the carbonization method was established.