Effect of Concrete Micro-Mechanical Properties under the Coupled Corrosion of Sulfate and High Water Head

Abstract

Large-scale water infrastructure such as immersed tunnels remain in a seawater environment for a long time, and gradually deteriorate under the action of high water head, soil pressure and corrosive ions in seawater solution. In order to simulate the corrosion damage and deterioration of concrete in seawater environment, 10% Na2SO4 solution was used to conduct indoor corrosion tests on concrete samples under different water heads and for different durations. The corrosion damage and micro-mechanical properties of concrete under the coupled action of high water head and sulfate are studied by micro-indentation tests. The effect of sulfate ion corrosion and complex mechanical loading was studied. The effect of micro-mechanical properties of concrete is studied on time and space. Numerical simulation and test results show that the results of micro-indentation are in good agreement with the fitting curves. The chemical damage rate and the corrosion depth increase with the increase of water head; the numerical simulation analysis shows that the sulfate concentration is high in the area where the mechanical damage variable is large, which indicates that the two kinds of corrosion occur in concrete and interact with each other.

Keywords

• micro-indentation
• high water head
• sulfate attack
• micromechanics