Kendiliğinden yerleşen betonlarda rötre azaltıcı katkı maddesinin dayanım ve dayanıklılığa etkisi
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Tarih
2017
Yazarlar
Dergi Başlığı
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Cilt Başlığı
Yayıncı
Kırıkkale Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, son yıllarda kullanım alanı gittikçe yaygınlaşan fakat henüz istenilen seviyeye gelmeyen, ileride geleneksel betonun yerini alması beklenen, özel bir beton türü olan Kendiliğinden Yerleşen Betonlarda(KYB), rötre azaltıcı katkı maddesi (SRA)'nın dayanım ve dayanıklılığa olan etkisi incelenmiştir. % 0,95 oranında polikarboksilat katkılı süperakışkanlaştırıcı kullanılarak elde edilen kontrol KYB ve optimum SRA dozajı belirlenerek SRA katkılı KYB numuneler üretilmiştir. Kontrol KYB ve SRA katkılı KYB numunelerin taze halde işlenebilme özellikleri, su kürü ve 28 günlük su kürünün akabinde, % 10 oranında Na2SO4 çözeltisinde, sertleşmiş halde dayanım ve dayanıklılık özellikleri incelenmiştir. SRA'nın betonun mekanik özelliklerini olumsuz yönde etkilediği, özellikle erken yaşlarda bunun daha belirgin olduğu görülmüştür. SRA katkısının, taze beton özelliklerini çok belirgin biçimde olmasa da etkilediği görülmüştür. SRA içeren numunelerin, kontrol numunelere kıyasla, kuruma rötresi değerlerini 7.günde yaklaşık % 40, 180. günde yaklaşık %27 oranında azalttığı görülmüştür. SRA'nın özellikle erken yaş kuruma rötreleri üzerinde daha etkili olduğu bulgusu elde edilmiştir. Kısıtlanmış rötre deneylerinde SRA katkısının kontrol numuneye göre, çatlama yaşını geciktirdiği ve 90.gün sonunda çatlak genişliğini yaklaşık %30 azalttığı gözlenmiştir.
In this study, the effect of Shrinkage Reducing Admixture (SRA) on the strength and durability of Self Compacting Concrete (SCC), which is a special type of concrete that is expected to replace conventional concrete in the future and has become widespread in recent years but not at the desired level, is examined. SCC samples with SRA were produced by determining the control SCC by using superplasticizer with %0,95 polycarboxylate admixture and optimal SRA dosage. Fresh workability properties of control SCC and SCC with SRA in normal water curing and after 28 days of curing; strength and durability properties of hardened concrete specimens which were exposed to %10 Na2SO4 solution, were examined. It has been found that SRA affects the mechanical properties of concrete negatively, especially in early ages. It can be said that SRA has a slight effect on fresh concrete properties. Samples containing SRA reduced drying shrinkage values by about %40 on 7th day and %27 on 180th day. It is obtained that SRA is more effective especially on early age shrinkage. In the restricted shrinkage tests, the SRA admixture delayed the cracking age according to the control sample and it was observed that the crack width was reduced by about 30% at the end of 90 days.
In this study, the effect of Shrinkage Reducing Admixture (SRA) on the strength and durability of Self Compacting Concrete (SCC), which is a special type of concrete that is expected to replace conventional concrete in the future and has become widespread in recent years but not at the desired level, is examined. SCC samples with SRA were produced by determining the control SCC by using superplasticizer with %0,95 polycarboxylate admixture and optimal SRA dosage. Fresh workability properties of control SCC and SCC with SRA in normal water curing and after 28 days of curing; strength and durability properties of hardened concrete specimens which were exposed to %10 Na2SO4 solution, were examined. It has been found that SRA affects the mechanical properties of concrete negatively, especially in early ages. It can be said that SRA has a slight effect on fresh concrete properties. Samples containing SRA reduced drying shrinkage values by about %40 on 7th day and %27 on 180th day. It is obtained that SRA is more effective especially on early age shrinkage. In the restricted shrinkage tests, the SRA admixture delayed the cracking age according to the control sample and it was observed that the crack width was reduced by about 30% at the end of 90 days.
Açıklama
Anahtar Kelimeler
İnşaat Mühendisliği, Civil Engineering, ,
