FLR technique Exchange kinetics of ethanol/fluorescent dye with water in water-saturated cement paste examined by ~1H- and ~2H-NMR

摘要

A water-saturated cement paste (water-to-cement, w/c=1.0) confined in a solution of ethanol saturated with a fluorescent dye showed complete exchange of water after 2 days. The exchange rates of water and ethanol were independent of the presence of dye and determined to be 42 X 10~(-8) and 60 X 10~(-8) cm~2/s, respectively. The exchange rate of dye was significantly smaller, by a factor of two to three. The exchange process resulted in a partitioning of the concentration of dye in ethanol within cement and bulk of (0.46+0.20). ~1H-NMR spectral analysis of the dye before and after exchange suggests the dye to be inert, i.e., it does not react with the cement paste. Furthermore, no indication of a reaction between ethanol and cement paste is observed.