WATER AND SALT MOVEMENT WITHIN MORTAR ANALYZED BY ASSUMING A CAPILLARY FLOW

摘要

In order to understand basic characteristics of salt movement within concrete within salty environment, one-dimensional water and salt movement within mortar was investigated by experiment and numerical analysis. The authors already reported concerning water and salt movement within mortar partially submerged in salty water. Water movement in that investigation was numerically analyzed applying a nonlinear diffusion equation. In spite of a fairly good result, a few discrepancies were recognized between analytical and experimental results for both the profiles of water and salt content. The discrepancies were considered to be caused by the application of the diffusion equation for the analysis of water movement. In the present analysis, the revised process based on capillary flow was adopted. The applied assumption adopted was that salt movement occurred by capillary flow, but did not occur by vapor diffusion. The analytical results are also compared with the experimental ones obtained as follows. The distribution of water content was obtained from the mass variation of each split piece between before and after oven drying. The distribution of salt content was obtained by potentiometric titration method using the pieces which were crushed into fine grains under 140μm. Fairly good coincidence of experimental and analytical results was obtained for both the profiles of water and salt contents. It means the present procedure is basically adequate for the analysis of water and salt movement within mortar.