This study is based on determination of the freeze-thaw resistance of air-entrained and non-air-entrained normal strength concrete (NC) and high strength concrete (HSC) produced with fly ash and silica fume according to surface scaling. The procedure allows us to measure the amount of scaling per unit surface area due to a number of well defined freezing and thawing cycles in the presence of deicing salt. The weight loss, surface scaling, moisture uptake, and internal damage were measured after 0 and after every 4th freeze-thaw cycle. The test results showed that the freeze-thaw resistance is influenced directly by the compressive strength property of the concrete. Silica fume significantly reduced the resistance of normal strength concrete against freeze-thaw effect without plasticizing agent. The surface scaling of silica fume concrete without admixture was 22% higher than reference normal concrete.

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In this study, it is aimed to present the relative activities and efficiencies of management operation and maintenance (MOM) services achieved by irrigation associations in Büyük Menderes Basin, Turkey. From the 16 irrigation associations operating and taking over the irrigation schemes which are under the operation and constructed by DSI (State Hydraulic Works) in the province of Aydın, the performance and efficiencies of eight irrigation associations having an area bigger than 1000 ha were evaluated. Efficiencies and performance related to MOM activities of irrigation associations were calculated and compared with methods of dissimilarity factor value. Furthermore, the construction costs per unit area utilizing the scheme type were calculated for the irrigation schemes researched. Financial self-sufficiency of irrigation associations in the basin was found to range from 1.64 to 0.79. Fee collection performance for Akçay Right Bank, Akçay Left Bank and Nazilli Left Bank irrigation associations was low, while it was satisfactory for Soke, Karpuzlu Yaylakavak, Aydin, Çine Topçam and Nazilli Right Bank irrigation associations. Financial stabilization and sustainability performance class for the eight irrigation schemes actualized between 'very poor' and 'average'. The cost of construction calculated per unit area researched ranged from US$5440 to 8500 ha‾ 1 .

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