THE EFFECT OF AGGREGATE MAXIMUM SIZE ON IMPACT RESISTANCE OF FIBER REINFORCED CONCRETE

In this study, the effect of maximum size of aggregate on impact resistance of fiber reinforced concrete were investigated. Using crushed limestone aggregate with 10, 15, 20 and 25 mm of maximum size, 8 different normal-steel fiber reinforced concretes were produced. Water/cement ratio and cement dosage of concrete mixtures are 0.5 and 400 kg/m3, respectively. Hooked-end bundled steel fibers with l/d ratio of 65 and 1.0% fiber volume were used in fiber concretes. After 28 days standard curing, compressive strength, split tensile strength and ultrasonic pulse velocity tests were performed on 150/150/150 mm cube specimens. Additionally, impact resistances of concrete specimens were determined using impact test apparatus described in ACI 544.3R-93. 150x300 mm cylinders were prepared for impact resistance tests. After 28 days curing, these specimens were cut and 150x64 mm special discs were prepared. Impact resistance test were performed on these special discs. Experimental results were evaluated corresponding to presence of steel fiber and aggregate maximum size.

ÇELÝK LÝFLÝ BETONLARIN DARBE DÝRENCÝNE AGREGA MAKSÝMUM BOYUTUNUN ETKÝSÝ

Bu çalýsmada çelik lifli betonlarýn darbe direncine, agrega maksimum dane boyutunun etkisi incelenmistir. Çalýsmada maksimum dane boyutu 10 mm, 15 mm, 20 mm ve 25 mm olan kireç tasý kökenli kýrma agrega kullanýlarak, 8 farklý lifsiz-çelik lifli beton üretilmistir. Üretilen lifli-lifsiz betonlarda; su/çimento oraný 0.50, çimento dozajý 400 kg/m3 olarak sabit tutulmustur. Lifli betonlarda hacimce % 1.0 oranýnda, narinligi 65 olan, iki ucu çengelli çelik lif kullanýlmýstýr. Üretilen betonlardan hazýrlanan 150 mm ayrýtlý küp örnekler üzerinde, 28 günlük standart kür sonunda tek eksenli basýnç, yarmada çekme ve ultra ses deneyleri yapýlarak, betonlarýn mekanik özellikleri belirlenmistir. Ayrýca, çalýsma kapsamýnda üretilen betonlarýn darbe testleri ACI 544.3R-93 ‘ce önerilen darbe deney düzenegi kullanýlarak gerçeklestirilmistir. Darbe testleri için 150 mm çaplý 300 mm yükseklikli örnekler hazýrlanarak 28 gün kür edildikten sonra, çapý 150 mm yüksekligi 64 mm olacak sekilde kesilerek özel diskler hazýrlanmýs ve bu diskler üzerinde darbe testleri yapýlmýstýr. Deneylerden elde edilen sonuçlar lif varlýgý ve agrega maksimum boyutunun degisimine baglý olarak degerlendirilmistir.