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

Abstract

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.

Keywords

• Impact effect, Aggregate maximum size, Fiber reinforced concrete, Mechanical properties.

ÇELİK LİFLİ BETONLARIN DARBE DİRENCİNE AGREGA MAKSİMUM BOYUTUNUN ETKİSİ

Öz

Bu çalısmada çelik lifli betonların darbe direncine, agrega maksimum dane boyutunun etkisi incelenmistir. Çalısmada maksimum dane boyutu 10 mm, 15 mm, 20 mm ve 25 mm olan kireç tası kökenli kırma agrega kullanılarak, 8 farklı lifsiz-çelik lifli beton üretilmistir. Üretilen lifli-lifsiz betonlarda; su/çimento oranı 0.50, çimento dozajı 400 kg/m3 olarak sabit tutulmustur. Lifli betonlarda hacimce % 1.0 oranında, narinligi 65 olan, iki ucu çengelli çelik lif kullanılmıstır. Üretilen betonlardan hazırlanan 150 mm ayrıtlı küp örnekler üzerinde, 28 günlük standart kür sonunda tek eksenli basınç, yarmada çekme ve ultra ses deneyleri yapılarak, betonların mekanik özellikleri belirlenmistir. Ayrıca, çalısma kapsamında üretilen betonların darbe testleri ACI 544.3R-93 'ce önerilen darbe deney düzenegi kullanılarak gerçeklestirilmistir. Darbe testleri için 150 mm çaplı 300 mm yükseklikli örnekler hazırlanarak 28 gün kür edildikten sonra, çapı 150 mm yüksekligi 64 mm olacak sekilde kesilerek özel diskler hazırlanmıs ve bu diskler üzerinde darbe testleri yapılmıstır. Deneylerden elde edilen sonuçlar lif varlıgı ve agrega maksimum boyutunun degisimine baglı olarak degerlendirilmistir.

Anahtar Kelimeler

• Darbe etkisi, Agrega maksimum tane boyutu, Çelik lifli beton, Mekanik özellikler.

Kaynakça

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