Damage analysis of sulfate erosion of pipe concrete under ultrasonic detection of wet and dry cycle conditions

Abstract

The majority of concrete research is focused on a single factor, and there is less research on concrete for drainage pipes, and the environmental aspects of its service are not fully considered. Most studies either focus on a single factor or use a high-temperature oven for baking concrete in order to simulate drying and wetting cycles. This, however, ignores the damage to the concrete caused by high-temperature baking, which is incompatible with the environment in which the pipeline concrete is buried underground, and the test results cannot accurately reflect the pipeline concrete's situation. The dry-wet cycle mode of immersion in MgSO4 solution and natural drying was used in the test to study the internal damage of C50 pipeline concrete in the sulfate environment. The influence of different concentrations of MgSO4 solution on the internal damage of concrete was analyzed using an ultrasonic wave on concrete specimens subjected to a dry-wetting cycle and 2.5%, 5%, and 10% concentrations of MgSO4 solution. The findings show that as the number of dry-wetting cycles and the concentration of MgSO4 solution increases, the internal damage of concrete continues to increase, the ultrasonic wave velocity in the concrete damage layer gradually decreases, and the thickness of the concrete damage layer gradually increases. The damage to the concrete gets worse as more MgSO4 solution is present, and the dry-wet cycle can speed up sulfate erosion.