Geopolymer Synthesis from Volcanic Ash Activated via Alkali-Fusion

Abstract

In this study, the usability and effectiveness of alkali-fused volcanic ashes as powder binders in geopolymer production were investigated. For this purpose, volcanic ash was mixed with powdered NaOH at predetermined ratios and subjected to high-temperature alkali fusion. The weight ratios of NaOH to volcanic ash were set at 0.6, 0.8, and 1.0. For each ratio, calcination was carried out separately at 550 °C and 700 °C, resulting in six different alkali-fused volcanic ashes. Geopolymer mortars were then produced using these materials. The alkali fusion process significantly disrupted the crystalline structures in volcanic ash and led to the formation of amorphous phases. Although the reactivity of volcanic ash increased through alkali fusion, the compressive strength of the resulting geopolymers did not improve.

Keywords

• Alkali-fusion
• Volcanic ash
• Geopolymer
• Compressive strength
• FTIR

Alkali-Füzyon Yöntemiyle Aktive Edilen Volkanik Küller ile Geopolimer Üretimi

Abstract

Bu çalışmada, alkali-füzyon işlemine tabi tutulan volkanik küllerin geopolimer üretiminde toz bağlayıcı olarak kullanılabilirliği ve bu yöntemin etkinliği araştırılmıştır. Bu kapsamda, volkanik kül ile toz haline getirilmiş NaOH belirli oranlarda karıştırılarak yüksek sıcaklıkta alkali-füzyon işlemi uygulanmıştır. NaOH’nin volkanik küle ağırlıkça oranı 0.6, 0.8 ve 1.0 olarak belirlenmiştir. Her oran için kalsinasyon işlemi 550 °C ve 700 °C sıcaklıklarda ayrı ayrı gerçekleştirilmiştir. Böylece toplam altı farklı alkali-füzyona uğramış volkanik kül elde edilmiştir. Elde edilen bu volkanik küller kullanılarak geopolimer harçlar üretilmiştir. Alkali-füzyon ile volkanik küldeki kristal yapılar önemli oranlarda kırılmakta ve amorf fazlar oluşmaktadır. Alkali-füzyon ile volkanik küllerin reaktivitesi artmasına karşın bu malzemeler ile üretilen geopolimerlerin basınç dayanımı, iyileşmemektedir.

Keywords

• Alkali-füzyon
• Volkanik kül
• Geopolimer
• Basınç dayanımı
• FTIR

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