عنوان مقاله [English]
Conveyance and Water distribution irrigation canals are one of the hydraulic structures that transports water supplied from sources such as diversion dams to drinking or agricultural uses. These canals are lined usually by materials such as concrete, stone and Sand cement mortar, asphalt linings to prevent water seepage losses along the flow path. Concrete that is used in irrigation canals is an unreinforced concrete with a thickness between 5 to 10 cm. Basic requirements of good concrete in hardened condition are satisfactory compressive strength and sufficient durability. After the implementation of each engineering structure, it is necessary to evaluate the project to determine the optimal performance and quality of implementation. Evaluation of the quality of irrigation linings is often carried out by the destructive and costly method of coring and carried out various experiments in the laboratory. Although destructive method yields relatively straightforward and straightforward results from the desired parameters, it also has some side effects that are sometimes difficult to recover. These include damage to the project, high cost, the need for extensive equipment and equipment, and the timeliness and sometimes stoppage of operation. These can include damage to the project, high cost, the need for extensive equipment and equipment, and the timeliness and sometimes stoppage of operation. Non-destructive testing methods can be used to prevent these complications. Electrical, ultrasonic and Schmidt hammer tests are among these. Nowadays, non-destructive testing of concrete has an effective and practical function in the repair of concrete structures. Non-destructive testing of concrete by providing data on various existing structures allows experts and experts to judge and decide on the performance, needs and methods of repair and restoration of concrete structures. The indicator of evaluation of the quality of concrete cover of irrigation canals in different environmental conditions is practically the same as non-irrigated structures based on the amount of compressive strength. The indicator to evaluation of the quality of concrete lining of irrigation canals in different environmental conditions is practically the same as non-irrigated structures based on the amount of compressive strength. The failure of hardened concrete due to repeated cycles of thawing and freezing in cold air in water structures (such as irrigation canals that can absorb water and saturate them) is more likely than other structures (Ramazanianpour and Shahnazari, 1988).
In this study, in order to establish a relationship between non-destructive testing (NDT) of Schmidt's Hammer number with destructive testing (DT) of compressive strength and water absorption parameters, 13 sections from 3 main conveyance canals were studied in Nahre Shaban irrigation network in Nahavand. At all sections, non-destructive testing of Schmidt's Hammer were determined, then from the same points, 12 and totally 156 cores were provided from 3 canals in this study. then relationship between Schmidt's Hammer No. with each of the parameters of laboratory experiments on the cores was investigated. Based on the results, Schmidt hammer number and compressive strength values have direct relationship with correlation coefficient of 86%. Also, the Schmitt Hammer and initial, boiled and capillary water have a reverse power relationship with a correlation coefficient of 72, 70 and 71 percent respectively. Considering these relationships with proper correlation, it is possible to estimate the durability parameters in through the non-destructive testing of the Schmidt hammer at the site. There is a direct relationship between the initial and boiled water absorption, with a correlation coefficient above 95%. Therefore, boiled water absorption capacity of cores, which requires more than 3 days, can be determined from the results of initial water absorption. There is an inverse relationship with grade of 3 with a correlation coefficient above 96% between boiled water absorption and compressive strength of cores. According to these results, for the evaluation of the durability of concrete, only the compressive strength parameter cannot be determined.