Karma lifli betonların tokluk açısından değerlendirilmesi

Abstract

Günümüzde farklı lifleri bir arada kullanarak elde ettiğimiz karma lifli beton ile betonun değişik özelliklerini iyileştirebilmekteyiz. Bu mükemmel malzeme konusundaki deneyimlerimiz her geçen gün artarak istenilen özellikte, amaca uygun ürünler elde edilmektedir. Yapılan çalışmalar neticesinde betonun gevreklik özelliğinden kurtarıp sünek bir malzeme haline getirmenin bir yolu da liflerin kullanılmasıdır. Bu çalışmada 11 farklı beton numune üretimi gerçekleştirilmiştir. Karışımlarda çelik lif miktarı, 20 kg/m3, 40 kg/m3 ve polipropilen lif miktarı ise 600 g/m3 alınmıştır. Karma lifli beton karışımlarında ise çelik lif 20 kg/m3, polipropilen lif ise 500 g/m3 miktarında karışıma eklenmiştir. Üretilen 150x150x550 mm lik kiriş ve 150 mm lik küp numuneler eğilme ve basınç deneylerine tabi tutulmuştur. Aynı su/çimento oranına sahip numunelerin eğilme deneyleri aracılığıyla yük-sehim diyagramları oluşturulmuştur. Her bir numune için kayıt altına alınan kırılma davranışına bağlı olarak numunelerin enerji yutma kapasiteleri yük-sehim diyagramları aracılığıyla ölçülmüştür. En iyi performansın karma lifli beton numunelerden elde edilmesi, Ülkemizin deprem kuşağında bulunması gerçeğine bağlı olarak depreme karşı sünek elemanlar üretmenin önemini bir kez daha vurgulamaktadır

Keywords

• hibrit lif, çelik lif, propilen lif, tokluk, eğilme

Evaluation of toughness of the hybrid fiber concrete

Abstract

It is known for its concrete brittleness feature a popular building material. The ductility of the structure of the delivery system, however, the concept is becoming important. The studies result in a concrete way to make a ductile material rescued from the brittleness feature is the use of fiber. The fibers used; steel, synthetic and naturebased materials. Our experience in this perfect material fit for purpose in every day products rose desired properties are obtained. By using different fibers together to obtain hybrid fiber concrete. Hybrid fiber concrete; Instead of a single fiber type and size is more than one type and size of a new cement -based composite material is contained in the mixture with the fiber. It intended to control the size of the cracks under load with hybrid fiber concrete. In this study 11 different types of concrete samples were produced. The amount of steel fibers in the mixture is 20 kg/m3 and 40 kg/m3 , the amount of polypropylene fiber is 600 g/m3 . In the mixedfiber concrete amount of steel fiber 20 kg/m3 and polypropylene fiber 500 g/m3 are considered. The specimens were tested under bending and compression. All experiments were carried out in the Balıkesir University's faculty of engineering and architecture building labs. Produced 150x150x550 mm beam samples and 150 mm cube samples are subjected to compressive and flexural tests. The same water/cement ratio concrete sample tests through bending loaddeflection diagrams are created. The energy absorbing capacity depending on the fracture behavior of the received record for each sample was measured. One of the aims of the work load energy absorption capacity of different types of samples depends on the deflection diagram to compare. The load deflection diagrams have been normalized to the same sample group. Plain concrete specimens are broken in a brittle whereas fiber concrete specimens showed a ductile behavior. Different test methods and specifications to determine their level of toughness of fiber concrete is available. In this study, toughness values were calculated according to the method given in TS 10515. Toughness index were found to be among the calculated values given in the specification. These values are given in the table 2. Depending on the experimental setup, the load -deflection curves were plotted to 8 mm deflection. Toughness values of all samples were compared. Toughness of fiber and hybrid fiber samples showed a significant increase. The best results were obtained from the behavior of the hybridfiber concrete samples, producing ductile element for our country in the earthquake zone, the importance of the earthquake behavior emphasizes once again.

Keywords

• hybrid fiber, steel fiber, polypropylene fiber, toughness, flexure.