Çelik lif katkılı betonlarda lif dağılımını etkileyen değişkenlerin etki düzeylerinin belirlenmesi
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Tarih
2022
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Tekirdağ Namık Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Günlük ihtiyaçların değişimi ve sürdürülebilir üretim istenilen beton özelliklerini etkilemektedir. Beton endüstrisi bu amaçla kendini sürekli geliştirmektedir. Lifli beton son yıllarda inşaat sektöründe yoğun olarak kullanılan beton türüdür. Bu nedenle lifli beton özelliklerinin tahmin edilebilirliği oldukça önem kazanmaktadır. Bu çalışmada lifli betonlarda lif dağılımını etkileyen etki değişkenlerinin lif dağılımı üzerindeki etki düzeylerinin belirlenmesi amaçlanmıştır.Çalışma kapsamında lif hacim oranı (%1, %2 ve %3), karıştırma süresi (5 dk., 8.5 dk. ve 12 dk.) ve lif uzunluğu (35 mm, 50 mm ve 60 mm) etki değişkeni, lif dağılımı ise tepki değişkeni olarak seçilmiştir. Lif dağılımının belirlenmesi için 15 deneme noktasında toplam 45 adet 150?150?600 mm boyutlarında kare prizma kiriş numuneleri üretilmiştir (beton sınıfı C30/37 seçilmiştir). Her bir numune üç ara kesite bölünmüştür. Kesitlerdeki lif dağılımları, göz ve dijital görüntü işleme yöntemi ile belirlenen lif adedinin numunedeki toplam lif adedine bölünmesiyle hesaplanmıştır. Seçilen etki değişkenlerinin lif dağılımı üzerindeki etki düzeyleri ANOVA ile belirlenmiştir. Ayrıca lif dağılımı ile ultrasonik atımlı dalga hızı ve eğilme dayanımı arasındaki etkileşim incelenmiştir. Bunlara ek olarak kalıplara beton döküm yönünün (mala yüzeyi alt bölgesi) kesitteki lif dağılımına etkisi de belirlenmiştir. En yüksek mala yüzeyi alt bölgesi lif dağılımı üçüncü ara kesitte %61.12,birinci ara kesitte ise 55.92'dir. Bu nedenle çalışma kapsamında üretilen beton için genel olarak beton döküm yönünün kesitteki lif dağılımının homojenliğini etkilemediği söylenebilir. Lif dağılımları üzerinde sadece lif uzunluğu değişkeni anlamlı etkiye (p –değeri < 0.0001) sahiptir. Birinci ve üçüncü kesit yüzeyi lif dağılımı için elde edilen modellerin R2 değerleri sırasıyla 0.9055 ve 0.9604 olarak elde edilmiştir. R2'lerin yüksek olması modellerin tahmin doğruluğunun yüksek olduğunu göstermektedir. Göz ile sayım sonucu elde edilen lif dağılım oranları ile dijital görüntü işleme yöntemi ile belirlenen lif dağılım oranlarının farkı maksimum 0.58'dir.
The variation in daily needs and sustainable production affect the desired concrete properties. The concrete industry is constantly improving itself for this purpose. Fiber concrete is a type of concrete that has been used extensively in the construction industry in recent years. For this reason, the predictability of fibrous concrete properties becomes important. This study, it was aimed to determine the effect levels of the variables affecting the fiber distribution in fibrous concretes on the fiber distribution. In the study, fiber volume ratio (%1, %2. and %3), mixing time(5 dk., 8.5 dk., and 12 dk.), and fiber length(35 mm, 50 mm, and 60 mm) were selected as the effect variables, and then fiber distribution was determined as the response variable. In order to determine the fiber distribution, a total of 45 square prism beam samples of 150?150?600 mm dimensions were produced at 15 trial points (concrete class C30/37 was chosen). Each specimen was divided into three cross-sections. The fiber distributions in the sections were calculated by dividing the fiber number determined by the eye and digital image processing (DIP) method by the total fiber number in the sample. The effect levels of the selected variables on the fiber distribution were determined by ANOVA. Moreover, the variations of the ultrasonic pulse velocity and bending strength according to fiber distribution was investigated. In addition, the effect of the direction of concrete casting into the molds (bottom area of the troweled surface) on the fiber distribution in the cross-section was also determined. The highest fiber distribution of the troweled surface lower region is 61.12% in the third cross-section and 55.92 in the first cross-section. Therefore, it can be said that for the concretes produced within the scope of the study, the direction of concrete casting does not affect the homogeneity of the fiber distribution in the cross-section. Only the fiber length has a significant effect level (p-value < 0.0001) on the fiber distributions. The R2 values of the models for the first and third cross-sectional surface fiber distribution were obtained as 0.9055 and 0.9604, respectively. The high R2 values indicate that the prediction accuracy of the models is high. The difference between the fiber distribution ratios obtained by the visual counting and the DIP method is a maximum of 0.58.
The variation in daily needs and sustainable production affect the desired concrete properties. The concrete industry is constantly improving itself for this purpose. Fiber concrete is a type of concrete that has been used extensively in the construction industry in recent years. For this reason, the predictability of fibrous concrete properties becomes important. This study, it was aimed to determine the effect levels of the variables affecting the fiber distribution in fibrous concretes on the fiber distribution. In the study, fiber volume ratio (%1, %2. and %3), mixing time(5 dk., 8.5 dk., and 12 dk.), and fiber length(35 mm, 50 mm, and 60 mm) were selected as the effect variables, and then fiber distribution was determined as the response variable. In order to determine the fiber distribution, a total of 45 square prism beam samples of 150?150?600 mm dimensions were produced at 15 trial points (concrete class C30/37 was chosen). Each specimen was divided into three cross-sections. The fiber distributions in the sections were calculated by dividing the fiber number determined by the eye and digital image processing (DIP) method by the total fiber number in the sample. The effect levels of the selected variables on the fiber distribution were determined by ANOVA. Moreover, the variations of the ultrasonic pulse velocity and bending strength according to fiber distribution was investigated. In addition, the effect of the direction of concrete casting into the molds (bottom area of the troweled surface) on the fiber distribution in the cross-section was also determined. The highest fiber distribution of the troweled surface lower region is 61.12% in the third cross-section and 55.92 in the first cross-section. Therefore, it can be said that for the concretes produced within the scope of the study, the direction of concrete casting does not affect the homogeneity of the fiber distribution in the cross-section. Only the fiber length has a significant effect level (p-value < 0.0001) on the fiber distributions. The R2 values of the models for the first and third cross-sectional surface fiber distribution were obtained as 0.9055 and 0.9604, respectively. The high R2 values indicate that the prediction accuracy of the models is high. The difference between the fiber distribution ratios obtained by the visual counting and the DIP method is a maximum of 0.58.
Açıklama
Anahtar Kelimeler
Lifli Beton, Lif Dağılımı, Dijital Görüntü İşleme, Ultrasonik Atımlı Dalga Hızı, Eğilme Dayanımı, Fiber Concrete, Fiber Distribution, Digital Image Processing, Ultrasonic Pulse Velocity, Bending Strength, İnşaat Mühendisliği, Civil Engineering
