نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه مهندسی آبیاری و آبادانی، دانشکده کشاورزی، دانشگاه تهران، کرج، ایران،
2 گروه مهندسی انرژی های نو و محیط زیست، دانشکده علوم و فنون نوین، دانشگاه تهران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Irrigation networks are the main infrastructures for water conveyance and distribution in agricultural sector. Chemical damage of concrete is one of the main limiting factors for service life of irrigation networks. The main target of this research was to investigate and compare the risk of chemical detriments on concrete structures of Golestan and Kausar-Nomal irrigation networks. In this regard, in June 2022, water samples were collected from different points of the studied networks and the laboratory tests were performed. Then, the results of the water-quality parameters in tandem with the previously available monthly water quality data of the studied networks, were analyzed based on credible international criteria and using water corrosiveness indices. The Ryznar index values, for both Golestan and Kausar-Nomel networks, during October 2021-June 2022, were beyond the threshold of water corrosiveness (6.8). The average values of Ryznar index for the water samples of Golestan and Kausar-Nomel networks were 7.45 and 8.15, respectively, which means the corrosiveness intensity of Kausar-Nomel network’s water is significantly higher. Also, the concentration of dissolved-CO2 in the water of Kausar-Nomel network, in June 2022, was equal to 31.7 mg/l, which means that there has been a risk of cement decomposition. On the other hand, during the nine studied months, the sulfate-ion concentration values in the Golestan network’s water were recorded more than 150 mg/l, which is more than the minimum required for reaction with concrete. In four months out of the nine studied months, the magnesium-ion concentration values in the Golestan network’s water were more than 100 mg/l which are the beyond of threshold risk in concrete chemical damages.
کلیدواژهها [English]
Comparisonal investigation of the risk of chemical water damages on concrete structures of Golestan and Kausar-Nomal irrigation networks, Iran
EXTENDED ABSTRACT
Irrigation networks are main infrastructures for water transfer and distribution in agricultural sector. One of the limiting factors for service life of irrigation networks is chemical damages of concrete. Among the chemical damages of concrete, one can mention cracking and spalling of concrete and corrosion of steel reinforcements embedded in concrete. On the other hand, in the situation of deficiency of calcium ion concentration in the water, hydraulic concrete structures will be exposed to the damage of leaching of cement materials from the concrete by corrosive water.
The purpose of the present study was to investigate and compare the risk of chemical damages on concrete structures in Golestan and Kausar-Normal irrigation networks.
In this study, water samples were collected from different parts of Golestan and Kausar-Nomel irrigation networks during field surveys in June 2022, and then the relevant water quality parameters were measured using standard laboratory methods. In order to investigate the corrosive properties of water in the studied irrigation networks, water corrosiveness indices were calculated by using the water quality parameters of the studied irrigation networks’ water. Also, in order to identify other factors of chemical damages on concrete and to determine the severity of chemical damages of concrete in the studied irrigation networks, internatoina credible criteria were used. In order to investigate the temporal changes of the intensity of chemical damages of concrete and their potential on damages of concrete structures in the Golestan and Kausar-Nomel irrigation networks, the available monthly water quality data of these irrigation networks were received from the Regional Water Company of Golestan Province.
Ryznar index for Golestan and Kausar-Nomel networks during October-2021-June-2022 has always exceeded the threshold value of water corrosiveness (6.8). However the average Ryznar index for the water of Golestan and Kausar-Nomel networks are equal to 7.45 and 8.15, respectively, and intensity of corrosiveness for the water of Kausar-Nomel network has significantly been higher. Moreover, the concentration of dissolved-CO2 in the water of Kausar-Nomel network in June 2022 was equal to 31.7 mg/liter, and there was a risk of cement decomposition. On the other hand, the analysis of the water quality of Golestan network based on the criteria for determining the severity of concrete chemical damage showed that during the studied period, the concentration of sulfate and magnesium ions in the water of Golestan irrigation network has been beyond the threshold risk of concrete chemical damages.
In all the nine studied months, the water of the Kausar-Nomel network has been corrosivenes, and in June 2022, the water of the Kausar-Nomal network has been very corrosive. During the studied period, in addition to the corrosiveness of the water in Golestan network, there has been also the risk of other chemical damages to the concrete in the Golestan network. In order to protect the concrete structures against chemical damages, appropriate measurs for improving the strength of concrete in corrosive environments must be taken.
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