Investigation of the Effect of Continuous Wetting and Drying Cycles on the Durability of the VarzanehWater Channel

Assessment of water conveyance channel durability, particularly under severe environmental conditions such as wetting and drying cycles, is of considerable importance. Moreover, the development of in-situ testing methods that enable rapid and cost-effective evaluation of structures without the need for concrete destruction plays a crucial role. In this study, the effects of continuous wetting and drying conditions on the permeability of concrete and the performance of the Varzaneh water conveyance channel were investigated. These conditions have resulted in significant water loss and reduced water transmission capacity. Considering that the methods introduced in international standards are generally destructive and only applicable in laboratory environments, the Cylindrical Chamber method was used in this research to measure concrete permeability. This method enables non-destructive, in-situ permeability measurement of concrete. The results indicated that the permeability of concrete increased significantly under wet-dry cycling conditions. To simulate the behavior of the canal’s concrete lining, laboratory concrete specimens were prepared, and the effects of various cycles of continuous wetting and drying on permeability were examined. Additionally, microstructural analysis of the concrete was performed to assess the impacts of these conditions. The findings revealed that wetting and drying conditions led to an approximate 17% increase in concrete permeability, which significantly compromises the integrity of the channel’s concrete body. Furthermore, three-dimensional plots were utilized to establish the relationship between compressive strength and permeability parameters. Proper curing was also found to reduce shrinkage cracks in concrete by about 20%. Therefore, to maintain optimal channel performance, it is essential to implement preventive measures and appropriate repairs.