Çimento ve alkali aktivasyonlu harçlarla kaplanmış hafif agregaların beton üretiminde kullanılabilirliğinin araştırılması
Küçük Resim Yok
Tarih
2024
Yazarlar
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Yayıncı
Düzce Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Dünyada, özellikle de Türkiye'de büyük rezerv alanına sahip olan pomza, kullanım alanı farklı birçok sektör olmasına rağmen, kullanım miktarı bakımından ülke ekonomisine katkı sağlayacak seviyelere ulaşamamıştır. Boşluklu yapısından dolayı yoğunluğu ve mekanik özellikleri düşük seviyededir. Bu nedenle taşıyıcı hafif beton uygulamalarında kullanımı tercih edilmemektedir. Ancak, pomza gibi boşluklu agregaların yüzeyleri kaplanarak mekanik özelliklerinde iyileştirme yapmak ve taşıyıcı hafif beton üretiminde kullanmak mümkündür. Bu çalışmada, pomza agregaları farklı özelliklere sahip çimento hamuru ve alkali aktive edilmiş harçlarla kaplanmıştır. Çimento hamurları, 0,50 - 0,55 su/çimento oranı ve 0,30 - 0,35 su/çimento oranı ile %1,5 süper akışkanlaştırıcı kullanarak elde dilmiştir. Alkali aktivasyonlu harçlar oluşturulurken, uçucu kül, su, kum ile alkali aktivatör olarak 8 mol, 10 mol ve 12 mol sodyum silikat (NaOH) ile sodyum hidroksit (Na₂SiO₃) sulu çözeltisi kullanılmıştır. Kaplamada kullanılan çimento hamuru ve alkali aktive edilmiş harçların, yayılma, Marsh hunisi akış süresi, basınç dayanımı ve eğilme dayanımı testleri gerçekleştirilmiştir. Kaplanan agregaların ise su emme, darbe dayanımı, tane dayanımı, özgül ağırlığı, gevşek birim hacim ağırlığı, mikro yapı incelemesi ve kaplanabilirlik özellikleri araştırılmıştır. Kaplanmış agregalarla üretilen betonların, fiziksel özelliklerinin yanı sıra basınç dayanımı, yarmada çekme dayanımı, eğilme dayanımı, kılcal su emme, yüksek sıcaklık, donma çözülme ve mikro yapıları incelenmiştir. Kaplamada kullanılacak malzemelerin akışkanlığının, kaplanma performansını artırdığı görülmüştür. Kaplanan agregaların tane dayanımlarında artış meydana geldiği ve su emme oranında %59'a kadar azalma sağlandığı tespit edilmiştir. Kaplanmış agregalarla üretilen betonların mekanik özelliklerinde (basınç dayanımı, yarmada çekme dayanımı, eğilme dayanımı) artış ve kılcal su emme miktarında azalmalar olduğu belirlenmiştir. Sonuç olarak, agregaların kaplanması ile performansının arttığı ve bunlarla üretilecek betonun taşıyıcı hafif beton özelliklerini taşıdığı tespit edilmiştir. Anahtar Sözcükler: Pomza, Yapısal Hafif Beton, Kaplanmış Agrega, Çimento Hamuru, Alkali Aktivasyonlu Harç
Pumice, which is abundant worldwide and particularly in Turkey, is utilized in various industries. However, its potential contribution to the national economy has not been fully realized due to underutilization. Due to its hollow structure, its mechanical properties are not satisfactory. For this reason, it is not preferred to be used in the production of structural lightweight concrete applications. However, it is possible to improve their mechanical properties by coating their surfaces and use them in the production of structural lightweight concrete. In this study, pumice aggregates were coated with cement paste and alkali activated mortars with different properties. Cement pastes, were obtained 0.50 and 0.55 water/cement ratio and by using %1,5 super plasticizer with 0.30-0.35 water/cement ratio while preparing alkaline activated mortars, fly ash, water, and sand were mixed with 8 mol, 10 mol, and 12 mol sodium silicate (NaOH) and sodium hydroxide (Na₂SiO₃) aqueous solutions as alkali activators. Slump-flow, Marsh funnel flow time, compressive strength and flexural strength of the cement paste and alkali activated mortars used in the coating were investigated. The water absorption, impact value, grain strength, specific gravity, loose density, microstructure, and coat ability properties of the coated aggregates were investigated. In addition to physical properties, compressive strength, splitting tensile strength, flexural strength, capillary water absorption, high temperature, freeze thaw and microstructure of concretes produced with coated aggregates were investigated. It was observed that the fluidity of the materials to be used in the coating improves the coating performance. It was determined that the grain strength of the coated aggregates increased and the water absorption rate decreased up to 59%. Increases in compressive strength, splitting tensile strength, flexural strength and decreases in capillary water absorption rate of concretes produced with coated aggregates were determined. As a result, it was determined that the performance of the aggregates increased as a result of coating and the concrete to be produced with them has the characteristics of lightweight concrete.
Pumice, which is abundant worldwide and particularly in Turkey, is utilized in various industries. However, its potential contribution to the national economy has not been fully realized due to underutilization. Due to its hollow structure, its mechanical properties are not satisfactory. For this reason, it is not preferred to be used in the production of structural lightweight concrete applications. However, it is possible to improve their mechanical properties by coating their surfaces and use them in the production of structural lightweight concrete. In this study, pumice aggregates were coated with cement paste and alkali activated mortars with different properties. Cement pastes, were obtained 0.50 and 0.55 water/cement ratio and by using %1,5 super plasticizer with 0.30-0.35 water/cement ratio while preparing alkaline activated mortars, fly ash, water, and sand were mixed with 8 mol, 10 mol, and 12 mol sodium silicate (NaOH) and sodium hydroxide (Na₂SiO₃) aqueous solutions as alkali activators. Slump-flow, Marsh funnel flow time, compressive strength and flexural strength of the cement paste and alkali activated mortars used in the coating were investigated. The water absorption, impact value, grain strength, specific gravity, loose density, microstructure, and coat ability properties of the coated aggregates were investigated. In addition to physical properties, compressive strength, splitting tensile strength, flexural strength, capillary water absorption, high temperature, freeze thaw and microstructure of concretes produced with coated aggregates were investigated. It was observed that the fluidity of the materials to be used in the coating improves the coating performance. It was determined that the grain strength of the coated aggregates increased and the water absorption rate decreased up to 59%. Increases in compressive strength, splitting tensile strength, flexural strength and decreases in capillary water absorption rate of concretes produced with coated aggregates were determined. As a result, it was determined that the performance of the aggregates increased as a result of coating and the concrete to be produced with them has the characteristics of lightweight concrete.
Açıklama
Anahtar Kelimeler
İnşaat Mühendisliği, Civil Engineering, Pumice, Structural Lightweight Concrete, Coated Aggregate, Cement Paste, Alkali Activated Mortar
