Study on Durability against Dry-Wet Cycles and Chloride Ion Erosion of Concrete Revetment Materials at the Water-Level-Fluctuations Zone in Yellow River Delta Wetlands

摘要

This study was aimed at exploring the durability of concrete revetment materials at the water-level-fluctuations zone of the Yellow River Delta Wetlands. The simultaneous effect of mineral admixtures (i.e., fly ash, slag, and silica fume) and polypropylene fiber on the resistance of concrete revetment materials to chloride erosion, was presented. Under the artificial simulation environment of dry-wet cycles and chloride ion (Cl-) erosion coupling, the evolutions of macro-mechanical properties and the microscopic composition of mineral admixtures-fiber-blend concrete was investigated via compressive strength tests and X-Ray Diffraction (XRD), Mercury Intrusion Porosimetry (MIP) test, for durations of 120 days. The results showed that, under the long-term dry-wet cycles and chloride ion coupling erosion, fly ash and slag provide additional Al(2)O(3)to react with Cl-, and tend to produce Friedel's salt with smaller interlayer spacing, thereby realizing concrete possessing higher chemical binding capacity with Cl-. The improvement in the physical adsorption capacity of concrete with Cl-, which was due to the formation of additional hydration products of calcium-silicate-hydrate (C-S-H) gel. These materials showed exhibited good resistance to dry-wet cycles and Cl(-)erosion resistance, and thus were deemed to be suitable for the preparations of concrete revetment materials at the water-level-fluctuations zone.