Effect of Fly Ash Additive and Freeze-Thaw Cycles on CBR Performance in Silty-Clayey Soils

Yıl 2025, Cilt: 3 Sayı: 2 , 146 - 159 , 30.12.2025

Ahmet Şenol , Defne Şahinbay

https://doi.org/10.66248/cumfad.1723609

https://izlik.org/JA68LC57HC

Öz

The soils in cold regions undergo changes in their structure, strength and permeability due to freeze-thaw cycles. The climate change experienced worldwide may threaten man-made infrastructures formed with soil fillings. This repeated freeze-thaw in cold climate regions will negatively affect many physical and mechanical properties of the soil. Therefore, considering the repeated freeze-thaw behaviors, there is a need to improve the soils in these regions that are sensitive to frost. The Sivas region is among our cities that are affected by this climate change and the very cold winter season. Therefore, how the clayey-silty soils frequently found in the Sivas region are affected by the freeze-thaw behavior as a result of their natural existence or use in road infrastructure and some foundation fillings was investigated with CBR experiments.
The main purpose of this study is to evaluate the effect of naturally occurring clayey-silty soils and freeze-thaw cycles with fly ash mixed in them on the California Bearing Ratio (% CBR). The effect of fly ash additive, which is also produced as a by-product in our thermal power plant, on clayey soil was examined by exposing it to different numbers of freeze-thaw cycles. For this purpose, mixtures made by adding fly ash to natural soil and soil at rates of 5-10-15% by weight were prepared in CBR test molds and after 96 hours of curing, they were exposed to freeze-thaw cycles in the form of 1-2-5 cycles and the volumetric changes after curing, freeze-thaw and CBR values were examined. The best result was obtained in the soil sample with 5% fly ash additive where there was no freeze-thaw. The soil sample formed by adding 5% fly ash additive to clayey soil provided benefit by increasing the CBR value by 228.94% compared to the soil sample formed from pure soil.

Anahtar Kelimeler

CBR , freeze-thaw , ; fly ash , ; silty-clay

Proje Numarası

M-2021-810

Uçucu Kül Katkı Maddesinin Ve Donma‐Çözülme Döngülerinin Siltli‐Killi Zeminlerde CBR Performansına Etkisi

https://izlik.org/JA68LC57HC

Öz

Soğuk bölgelerdeki zeminler, donma-çözülme döngüleri nedeniyle yapılarında, mukavemetinde ve geçirgenlik özelliklerinde değişikliğe uğrarlar. Dünya genelinde yaşanan iklim değişikliği zemin dolguları ile oluşturulan insan yapımı altyapıları tehdit edebilir. Soğuk iklim bölgelerinde tekrar eden bu donma-çözülme, zeminin fiziksel ve mekanik birçok özelliğini olumsuz etkileyecektir. Bu yüzden tekrarlı donma-çözülme davranışları göz önüne alınarak bu bölgelerde bulunan ve dona karşı hassas zeminlerin iyileştirilmesine ihtiyaç vardır. Sivas yöresi, yaşanan bu iklim değişikliğinden ve kış mevsiminin oldukça soğuk geçmesinden etkilenen şehirlerimizin içerisinde bulunmaktadır. Bu nedenle Sivas bölgesinde sıklıkla bulunan killi-siltli zeminlerin yol alt yapısında ve kimi temel altı dolgularında, doğal olarak var olması veya kullanılması sonucunda donma-çözülme davranışından nasıl etkilendikleri CBR deneyleri ile araştırılmıştır. Bu çalışmanın temel amacı, doğadan çıktığı haliyle killi-siltli zeminlerin ve uçucu kül karıştırılmış olarak donma-çözülme döngülerinin Kaliforniya Taşıma Oranı (% CBR) üzerindeki etkisini değerlendirmektir. Killi zeminin içerisine yine yöremiz termik santralinde bir yan atık ürün olarak üretilen uçucu kül katkısının yaratabileceği etki farklı sayıdaki donma-çözülme döngülerine maruz bırakılarak incelenmiştir. Bunun için doğal zemine ve zeminin ağırlığının % 5-10-15 oranlarında uçucu kül katılarak yapılan karışımlar CBR deney kalıplarında hazırlanmış ve 96 saat kürlenme sonrası 1-2-5 döngü olacak şekilde donma-çözülmeye maruz bırakılarak kürlenme, donma-çözülme sonrası hacimsel değişimler ve CBR değerleri incelenmiştir. En iyi sonuç donma-çözülmenin olmadığı %5 uçucu kül katkılı zemin numunesinde meydana gelmiştir. Killi zemine %5 uçucu kül katkısı eklenerek oluşan zemin numunesi saf zeminden oluşan zemin numunesine göre CBR değerini % 228,94 oranında artırarak fayda sağlamıştır.

Anahtar Kelimeler

donma-çözülme , silt-kil , uçucu kül , CBR

Destekleyen Kurum

Sivas Cumhuriyet Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimi (CÜBAP, Proje Numarası: M-2021-810) tarafından desteklenmiştir.

Proje Numarası

M-2021-810

Teşekkür

Sivas Cumhuriyet Üniversitesi Bilimsel Araştırma Projeleri Koordinasyon Birimine verdiği destekten dolayı teşekkür ederiz

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