Salih Taner YILDIRIM, Cevdet Emin EKİNCİ

Çelik, cam ve polipropilen lifli betonlarda donma-çözülme etkilerinin araştırılması

Bu çalışmada, polipropilen, cam ve çelik lifli betonların dona dayanıklılıkları araştırılmıştır. Deneyler için, lifsiz, polipropilen, cam, çelik ve karışık lifli 12 farklı beton üretilmiştir. Beton karışımında mikro yapılı çapı 50 $mu$, boyut oranı 400 polipropilen ve çapı 14 $mu$, boyut oranı 857 olan cam lifler ile makro yapılı çapı 0.75 mm, boyut oranı 80 olan çelik lifler kullanıldı. %0.5, 0.75 ve %1 hacimsel oranında çelik lifler, beton içinde %0.1 hacimsel oranında polipropilen ve cam liflerle karışık ve ayrı ayrı kullanıldı. Deneyler ASTM C 666 standardından havada hızlı donma-çözülme koşulları dikkate alınarak yapılmıştır. 30 donma-çözülme çevrimi sonucunda hazırlanan numuneler üzerinde ağırlık kaybı, ultrases geçiş hızı ve dayanıklılık faktörü değerleri belirlenmiştir. Deney sonuçları, betonda kullanılan lif tipine göre değerler arasında önemli farklılıklar olduğunu göstermiştir.

The effect of freeze-thaw on the steel, glass, and polypropylen fiber reinforced concrete

Durability of concrete reinforced by fiber, polypropylene, glass and steel against the effects of freeze-thaw was investigated in this study. Plain, polypropylene, glass, steel and hybrid 12 concrete specimens were produced The polypropylene fibers in diameter of 50 $mu$, aspect ratio of 400, glass fibers in diameter of 14 $mu$, aspect ratio of 857 and steel fibers in diameter of 0.75 mm, aspect ratio of 80 were used in concrete mixtures. The volumetric contents were 0.5, 0.75 and 1% in steel fiber reinforced concretes. The volumetric content was 0.1% in polypropylene and glass fiber reinforced concretes. The experiments of rapid freeze-thaw in the air were taken as the basis according to the criteria of ASTM C 666. Values of weight-loss and of the durability factor, which was determined by pulse velocity, in the specimens were evaluated after 30 freeze-thaw cycles. Experiments results were determined to be significantly different from one another according to the type of the fiber used in the concrete.

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