Pamukkale Univ Muh Bilim Derg. 2021; 27(3): 274-280 | DOI: 10.5505/pajes.2020.34846

Bond strength of full-scale beams with blended short and long steel fiber

Kâzým Türk¹, Mahmut Baþsürücü^2
1Department of Civil Engineering, Inonu University, Malatya, Turkey
²Department of Construction Technology, Malatya Turgut Ozal University, Malatya, Turkey

In this study, six reinforced concrete (RC) beams with the sizes of 200x300x2000 mm were tested under four-point bending to investigate the effect of single and hybrid fiber reinforced on the bond strength of reinforcing bar. For this purpose, the reinforced beams were cast as no fiber, single fiber (1% macro steel fiber) and hybrid fiber (0.8% macro and 0.2% micro steel fiber) reinforced. Each beam was designed to include two bars in tension, spliced at the center of the span. The splice length was selected so that bars would fail in bond, splitting the concrete cover in the splice region, before reaching the yield point. In experimental work, the diameter of bars, splice length and bar details was selected as constant while the fiber type and combination was variable. Finally, it was found that all beams with steel fiber reinforced had higher bond strength between concrete and steel bar than the beams without steel fiber while the beams with hybrid steel fiber reinforced had highest bond strength. A ductile failure was observed in the hybrid fiber reinforced beam specimens and it was determined that the result of multiple-crack behavior less crack width but more numbers cracked. Moreover, experimental data related to the bond strength obtained from RC beams with steel fiber were in very good agreement with analytical results.

Keywords: Bond strength, Splice length, Hybrid-fiber reinforced concrete, Full-scale RC beams, Fiber combination

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Uzun ve kýsa çelik lif takviyeli tam ölçekli kiriþlerin aderans dayanýmý

Kâzým Türk¹, Mahmut Baþsürücü^2
1Ýnönü Üniversitesi, Ýnþaat Mühendisliði Bölümü, Malatya, Türkiye
²Malatya Turgut Özal Üniversitesi, Ýnþaat Teknolojisi Programý, Malatya, Türkiye

Bu çalýþmada, tek ve karma lif takviyesinin aderans dayanýmýna etkisini incelemek için altý adet tam ölçekli 200x300x2000 mm boyutlarýnda betonarme kiriþ numunesi dört noktalý eðilme altýnda test edilmiþtir. Bu amaçla, betonarme kiriþ numuneleri lif takviyesiz, tek lif (%1 makro çelik lif) ve karma lif (%0.8 makro ve %0.2 mikro çelik lif) takviyeli olarak döküldü. Her bir kiriþ numunesi, çekme bölgesinde iki adet donatý çeliðinin açýklýk ortasýnda bindirmeli ekli olarak tasarlanmýþtýr. Bindirme boyu donatýnýn akma dayanýmýna ulaþmadan önce bindirme bölgesinde beton örtüsünün yarýlmasýyla aderans göçmesi gösterecek þekilde seçilmiþtir. Deneysel çalýþmada, donatý çapý, bindirme boyu ve donatý detaylarý sabit tutulurken, lif tip ve kombinasyonlarý deðiþken olarak belirlenmiþtir. Sonuç olarak, lif takviyeli tüm betonarme kiriþ numunelerinin beton ve çelik donatý arasýndaki aderans dayanýmý, lif takviyesiz kiriþ numunelerine göre artýþ gösterirken, karma lif takviyeli kiriþ numunelerinin aderans dayanýmý ise en yüksek bulunmuþtur. Karma lif takviyeli kiriþ numunelerinde sünek göçme gözlemlenmiþ ve çoklu çatlak davranýþý sonucu geniþliði daha az fakat daha fazla sayýda çatlak oluþtuðu belirlenmiþtir. Ayrýca, lif takviyeli kiriþ numunelerinden elde edilen aderans dayanýmýna ait deneysel verilerin, analitik bulgularla çok iyi bir uyum içinde olduðu bulunmuþtur.

Anahtar Kelimeler: Aderans dayanýmý, Bindirme boyu, Karma lif takviyeli beton, Tam ölçekli betonarme kiriþ, Lif kombinasyonu

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