THE ANALYSIS OF CAPILLARY PORES IN CARBONATED CEMENT

Abstract

The carbonation of cement stone is one of the key processes affecting the durability of reinforced concrete structures, particularly in aggressive environment. This study aims to analyze the microstructural changes of cement stone during the carbonation process using scanning electron microscopy (SEM). Special attention is given to the quantitative assessment of capillary porosity, which influences both the mechanical and diffusion properties of the material. The research employs image binarization techniques, morphological analysis of the pore structure, and statistical data processing using analysis of variance (ANOVA). The study reveals the decrease in the cement stone porosity from 18.7 to 7.9%, accompanied by a reduction in compressive strength from 42.5 MPa to 11.5 MPa. The experimental data are compared with diffusion models, including Fick’s model and the percolation model. The percolation model more accurately reflects the decline in the material’s diffusivity upon reaching the critical porosity threshold. The novelty of this research is comprehensive analyzing carbonation processes, combining SEM techniques, mathematical modeling, and statistical analysis. The results can be used to predict the durability of concrete structures and to optimize repair mortar compositions