Strength Development of Heat Cured and Ambient Cured Sodium Hydroxide Activated Fly Ash Based Geopolymer

Year 2020, Volume: 9 Issue: 2, 79 - 88, 31.12.2020

Cengiz Atiş , Omeed Adwal Ali Ali , Uğur Durak , Serhan İlkentapar , Okan Karahan

Abstract

Compressive strength development of class F fly ash geopolymer activated by sodium hydroxide was compared between initial heat curing at 75ºC for 24 hours and the ambient medium. Class F geopolymeric mortar was produced with standard Rilem sand, sodium hydroxide, and water. Mortar mixtures ratios were 3, 1, and 0.288 for sand, fly ash, and water, respectively. Some samples were cured in laboratory conditions; some samples were heat cured for 24 hours at 75ºC. Ambient curing medium result with non-measurable low compressive strength up to 7 days, however significant strength development observed in longer curing time up to six months. Heat curing developed higher strength at all times than ambient curing did. It was concluded that heat cured geopolymer samples could be utilized in construction materials, while utilization of non-heat cured samples was not practical due to its longer curing duration needs.

Keywords

Geopolymer, Fly ash, Heat curing, Compressive strength

Sodyum Hidroksit ile Aktifleştirilmiş Uçucu Kül Bazlı Geopolimerlerin Isıl Kür ve Ortam Küründe Dayanım Gelişimi

Abstract

Sodyum hidroksit ile aktifleştirilmiş F sınıfı uçucu kül geopolimerinin basınç dayanımı gelişimi, 75ºC'de 24 saatlik ilk ısıl kürleme ile laboratuvar ortamı arasında karşılaştırılmıştır. F sınıfı geopolimerik harç, standart Rilem kumu, sodyum hidroksit ve su kullanılarak üretilmiştir. Harç karışım oranları kum, uçucu kül ve su için sırasıyla 3, 1 ve 0.288 olarak kullanılmıştır. Üretilen numunelerin laboratuvar ortamında ve 75ºC'de 24 saat ısıda ayrı ayrı bekletilerek kür edilmiştir. Ortam şartlarında bekletilen numunelerde 7 güne kadar ölçülemeyen düşük basınç dayanımları elde edilmiştir. Ancak altı aya kadar daha uzun kürleme süresinde önemli bir dayanım gelişimi gözlenmiştir. Isı ortamında kürlenen numuneler her zaman ortam kürüne göre daha yüksek dayanım sonuçları vermiştir. Isı ile kürlenen geopolimer numunelerin inşaat malzemelerinde kullanılabileceği, ısı ile kürlenmemiş numunelerin kullanımının ise daha uzun kürlenme süresi ihtiyaçları nedeniyle pratik olmadığı sonucuna varılmıştır.

Keywords

Geopolimer, Uçucu kül, Isıl kür, Basınç dayanımı

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