| Autor: |
Pablo-Calderón MA; CIIDIR Unidad Oaxaca, Instituto Politécnico Nacional, Calle Hornos No. 1003, Colonia Noche Buena, Sta. Cruz Xoxocotlán, Oaxaca 71230, Mexico., Cano-Barrita PFJ; CIIDIR Unidad Oaxaca, Instituto Politécnico Nacional, Calle Hornos No. 1003, Colonia Noche Buena, Sta. Cruz Xoxocotlán, Oaxaca 71230, Mexico., León-Martínez FM; CIIDIR Unidad Oaxaca, Instituto Politécnico Nacional, Calle Hornos No. 1003, Colonia Noche Buena, Sta. Cruz Xoxocotlán, Oaxaca 71230, Mexico. |
| Abstrakt: |
Surface electrical resistivity is a non-destructive technique that is sensitive to the microstructure of hydrated cement paste and the chemical composition of the pore solution in cement-based materials. In this study, a Wenner array was used to measure changes in mortar resistivity due to chloride ion diffusion as a function of electrode separation. Specimens were made from four mortar mixtures: 100% Ordinary Portland cement and 60% cement + 40% fly ash at two water/binder ratios of 0.55 and 0.40. The specimens were subjected to unidirectional chloride ion diffusion in a 2.8 M NaCl solution for 175 days. To determine the chloride penetration depth, three methods were used: silver nitrate spraying, chloride concentration profiles via potentiometric titration, and chloride concentration profiles via inversion of the resistivity data using the RES1D software (version 1.00.09 Beta). The results showed a linear relationship between the chloride ion penetration depth obtained via inversion of the surface electrical resistivity data versus the penetration depth from colorimetry and from chloride concentration profiling (both with R 2 = 0.8612). Chloride penetration changed the conductivity of the pore solution; therefore, the resistivity decreased when increasing both the chloride concentration and the penetration depth. Inversion of surface resistivity data obtained with a Wenner array permitted non-destructive determination of chloride penetration. However, these results were obtained under laboratory environmental conditions and other scenarios must be addressed for wider applications. |
