Abstract
Wick action is the key factor in understanding the salt weathering of porous materials. In this study, concrete discs were partially exposed to Na2SO4 solution to simulate the wick action in concrete. We evaluated the effects of the relative humidity (RH), solution concentration, and pore structures (different water to cement ratios) on the solution transport mechanism based on the water evaporation rate. Interestingly, we found that lower RH and larger W/C ratio accelerated evaporation, but the higher concentration of the solution slowed it down. The micro-analyzer results of NMR and XRD confirmed that the formation of ettringite and gypsum due to chemical sulfate attack blocked the pores in the concrete, resulting in a decrease in water evaporation. Na2SO4 crystallization distress was not detected in the concrete. Therefore, the solution transport process in the concrete discs could not be described by wick action.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Acknowledgments
We express our gratitude to the Central South University for providing instruments and materials. Special thanks are due to Professor Zanqun Liu for the guidance and assistance in the design of the test scheme and the process of writing this paper.