ÇELÝK LÝF DONATILI BETONUN EÐÝLME TOKLUÐU

Lifli beton, donatýsýz betondan farklý mekanik ve fiziksel özelliklere sahip bir kompozit malzemedir. Lifli betonun en önemli mekanik özeliklerinden birisi enerji yutabilme kapasitesidir. Tokluk olarak da adlandýrýlan bu özellik, yük-sehim eðrisinin altýnda kalan alan ile ifade edilir. Çatlak direnci, düktilite, darbe direnci gibi birçok malzeme özelliði enerji yutabilme kapasitesi ile iliþkilidir. ASTM C 1018 ve JSCE SF-4’e göre yapýlan tokluk hesaplamalarý bir eksenli eðilme deneylerine göredir. Oysa; köprü tabliyeleri, park sahalarý, havaalaný kaplamalarý vb. yapýlarda sýkça uygulanan lifli beton, bu elemanlarda plak davranýþýna sahiptir. Bu çalýþmada , tokluk ASTM C 1018 ve JSCE-SF4 ’e göre kiriþ testlerinden hesaplanarak, donatýsýz ve çelik lifli betonun enerji yutma kapasiteleri karþýlaþtýrýlmýþtýr. Tokluk hesabýnda kullanýlan iki metodun birbirine göre deðerlendirmesi yapýlmýþtýr. Ayrýca, iki eksenli eðilme altýnda,donatýsýz ve çelik lifli beton plak numunelerin davranýþlarý her bir numunenin deneylerinden elde edilen yük-sehim diyagramlarý aracýlýðýyla karþýlaþtýrýlmýþtýr.

FLEXURAL TOUGHNESS OF STEEL FIBER REINFORCED CONCRETE

Fiber concrete is a composite material which has mechanical and physical characteristics unlike plain concrete. One of the important mechanical characteristics of fiber concrete is its energy absorbing capability. This characteristics which is also called toughness, is defined as the total area under the load-deflection curve. A number of composite characteristics such as crack resistance, ductility and impact resistance are related to the energy absorbtion capacity. According to ASTM C 1018 and JSCE SF-4 the calculation of toughness is determined by uniaxial flexural testing. Fiber concrete is often used in plates such as bridge decks, airport pavements, parking areas, subjected to cavitation and erosion. In this paper, toughness has been determined according to ASTM C 1018 and JSCE SF-4 methods by testing beam specimens. Energy absorbing capacities of plain and steel fiber reinforced concrete has been compared by evaluating the results of two methods. Also plain and steel fiber reinforced plate specimens behaviors subjected to biaxial flexure are compared by the loaddeflection curves of each specimen.