The corrosive seawater environment poses significant challenges to the stability and durability of anchor structures in underground engineering. Among them, the corrosion degree of anchor structure is affected by many factors such as the performance of the grouting material, the corrosion age, and the stress state, and the corrosion resistance of the grouting material is the key issue of seawater corrosion resistance.
To this end, the research team of Wuhan Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, developed a new corrosion-resistant high-strength grouting material based on the preparation of ferroaluminate cement clinker, ordinary Portland cement, anhydrite and limestone powder. Artificial seawater solutions with different salt concentrations were used to carry out accelerated erosion tests by full immersion. Through uniaxial compression test, X-ray diffraction test, thermogravimetric analysis test, mercury pressure test and other test techniques, the researchers systematically studied the evolution of mechanical properties, expansion rate, chloride ion content, hydration products, microstructure and other performance indicators of new high-strength grouting materials. The results show that the uniaxial compressive strength of the high-strength grouting material increases first and then decreases with the increase of corrosion age, and the corrosion resistance coefficient of the specimen changes between 0.95~1.30. With the increase of corrosion age, the quality and expansion rate of the grouting material increase logarithmically. The high-strength grouting material absorbs sulfate ions in seawater, thereby promoting the formation of calcium alum to resist sulfate corrosion. In addition, it was found that Friedels salt is mainly produced by the sulfate ion exchange between chloride and monothioaluminate. The experimental results confirm that the developed new high-strength grouting material has excellent salt corrosion resistance and good mechanical stability in seawater, and reveals the macroscopic characteristics of the erosion deterioration evolution process of the new grouting material under seawater erosion environment.
The research was published in Construction and Building Materials. The research work has been funded by the National Natural Science Foundation of China, the National Key Research and Development Program of China and other projects. (Source: Wuhan Institute of Rock and Soil Mechanics, Chinese Academy of Sciences)
Related paper information:https://doi.org/10.1016/j.conbuildmat.2023.131056
Fig. 1 Effect of corrosion age and seawater salt concentration on compressive strength (a) Uniaxial compressive strength; (b) Corrosion resistance coefficient
Fig. 2 Evolution of hydration products at different seawater salt concentrations
Fig. 3 The variation of sulfur content in material systems under different salt concentrations and corrosion ages (a) 0.5a, (b) 1.0a, (c) 1.5a
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