Uçucu Külle Stabilize Edilen Çatalağzı Kili Mühendislik Performansı

Öz

Zeminlerin stabilizasyonu fiziksel, kimyasal ve hidrolik yöntemler ile yapılabilmektedir. Kimyasal stabilizasyon, bu yöntemlerin arasından en yaygın kullanılanıdır. Bu çalışmada, düşük plastisiteli Çatalağzı kil numunesi araştırma malzemesi olarak seçilmiştir. F tipi uçucu kül kimyasal katkı olarak kullanılmıştır. Zemin çeşitli oranlarda (0%, 10%, 20% ve 30%) uçucu kül ile karıştırılmıştır. Killi zemin üzerinde indeks deneyleri (hidroemetre, özgül ağırlık, likit limit, plastik limit ve standart kompaksiyon) gerçekleştirilmiştir. Sonra, standart kompaksiyon deneyinden elde edilen optimum su içeriğinde hazırlanan numuneler, serbest basınç (UCS), nemlilik şartları (MCV) ve Kaliforniya taşıma oranı (CBR) deneyine maruz kalmıştır. Kür süresi UCS deneyi için 0, 7 ve 28 gün olarak seçilmiştir. CBR deneyindeki kür 28 gün havada kürlerme ve 4 gün tam suda beklemeyi içermektedir. MCV için kür süresi yoktur. Uçucu kül ilavesi zeminin UCS değerini artırmaktadır. S10FA, S20FA ve S30FA numunelerine ait 7 gün kürlü durumdaki UCS değerleri, kür süresiz Çatalağız kilinin 1.46, 1.51 ve 1.53 katıdır. UCS artış hızı 7 günden sonra yavaşlamaktadır. S10FA için MCV 18.3 iken Çatalağzı kili için 12.2 olmuştur bu da yaklaşık 50% artış anlamına gelmektedir. Uçucu kül katkı oranı 10%’den sonra önemli bir değişim olmamış hatta biraz azalmıştır. CBR değerleri de uçucu kül ilavesi ile artmıştır. Uçucu külün, kilin mühendislik performansının artırdığı fakat CBR değeri düşünüldüğünde yol alt dolgusu olmak için yeterli olmadığı sonucuna varılmıştır.

Anahtar Kelimeler

• Killi zemin
• Kaliforniya taşıma oranı
• Uçucu kül
• Nemlilik şartları
• Serbest basınç

Engineering Performance of Fly Ash Stabilized Çatalağzı Clay

Abstract

Stabilizing of soils can be done with physical, chemical and hydraulic methods. Chemical stabilization is one of the most widely used method among them. In this study, low plasticity Çatalağzı clayey soil is chosen as a research material. F type of fly ash are used as a chemical additive. Soil is mixed with various amount (0%, 10%, 20% and 30%) of fly ash. Index tests (hydrometer, specific gravity, liquid limit, plastic limit and standard compaction) were performed on clayey soil. Then samples prepared with optimum water content obtained from standard compaction test were exposed to unconfined compressive strength (UCS), moisture condition value (MCV) and California bearing ratio (CBR) tests. Curing time are selected as 0, 7 and 28 days for UCS test. Curing for CBR test includes 28 days air curing and 4 days full soaking. MCV has no curing time. Addition of fly ash increase the UCS of untreated soil. UCS of samples for S10FA, S20FA and S30FA having 7 day of curing time is 1.46, 1.51 and 1.53 times of the Çatalağzı clay of having no curing time. Rate of increase in UCS gets slow down after 7 days. MCV of S10FA is 18.3 while it is 12.2 for Çatalağzı clay which means 50% increase. Fly ash content after 10% have no significant change and even decrease slightly. CBR values are increased with an addition of fly ash also. It has been concluded that this type of fly ash increases the engineering performance of untreated clay but it is not suitable to be a subgrade for highway when taking into account of CBR value

Keywords

• Clayey soil
• California bearing ratio
• Fly ash
• Moisture condition value
• Unconfined compressive strength

Kaynakça

1. Türker, P., Erdoğan, B, Katnaş, F., & Yeğinobalı, A. (2009). Classification and properties of fly ash in turkey” Turkish Cement Manufacturers Association, Tech. Rep. TÇMB /ARGE / Y03.03. (in Turkish).
2. Pandian, N. S., Krishna, K. C., & Sridharan A. (2001). California bearing ratio of soil/fly ash mixtures. Journal of Testing and Evaluation, 29(2), 220-226.
3. Altun S., Sezer, A., & Erol A. (2009). The effect of additives on the mechanical behavior of a silty soil. Cold Regions Science and Technology, 56, 135–140.
4. Brooks, R., Udeyo, F. F., & Takkalapelvi, K. V. (2011). Geotechnical properties of problem soils stabilized with fly ash. Journal of Materials in Civil Engineering, 23(5), 711-716.
5. Mccarthy, M. J., Csetenyi, L. J., Sachdeva, A., & Dir, R. K. (2014). Engineering and durability properties of fly ash. Engineering Geology, 174, 139-148.
6. Yao, Z. T., Ji, X. S., Sarker, P. K., Tang, J. H., Ge, L. Q., Xia, M. S., & Xi, Y. Q. (2015). A comprehensive review on the applications of coal fly ash. Earth-Science Reviews, 141, 105-121.
7. Dayıoğlu, M., Çetin, B., & Nam, S. (2017). Stabilization of expansive belle fourche shale clay with different chemical. Applied Clay Science, 146, 56–69.
8. Priyadarshee, A., Kumar, A., Gupta, D., & Pushkarna, P. (2018). Compaction and strength behavior of tire crumbles-fly ashed mixed with clay. Journal of Materials in Civil Engineering, 30(4), 1-9.

9. Miricioiu, M. G., & Niculescu V. C. (2020). Fly ash, from recycling to potential raw material for mesporous silica synthesis. Nano Materials, 10(3), 474.
10. ASTM D7928-17 (2017), Standard test method for particle-size distribution (gradation) of fine-grained soils using the sedimentation (hydrometer analysis)1, ASTM Standard.
11. ASTM D2487-17ε1 (2017). Standard practice for classification of soils for engineering purpose (unified soil classification system)1, ASTM Standard.
12. ASTM D698-12ε2 (2012). Standard test methods for laboratory compaction characteristics of soil using standard effort (12400 ft-lbf/ft3 (600 kN-m/m3))1, ASTM Standard.
13. ASTM C618 (2019). Standard specification for coal fly ash and raw or calcined natural pozzolan for use in concrete1, ASTM Standard.
14. ASTM D2166/D2166M-16 (2016). Standard test method for unconfined compressive strength of cohesive soil, ASTM Standard.
15. BS EN 13286-46 (2003). Unbound and hydraulically bound mixtures part 46: test method for the determination of the moisture condition value, BSI Standard Publications, British Standard.
16. BS EN 13286-47 (2012). Unbound and hydraulically bound mixtures part 47: test method for the determination of california bearing ratio, immediate bearing index, and linear swelling, BSI Standard Publications, British Standard.
17. KGM (2013). Highway technical specification (infrastructures, engineering structures, bridges and tunnels, pavement and miscellaneous constructions), General Directorate of Highways.
18. Mahedi, M., Çetin, B., & White D. J. (2020). Cement, lime and fly ashes in stabilizing expansive soils: Performance evaluation and comparison. Journal of Materials in Civil Engineering, 32(7). 04020177.
19. Matheson, G. D., & Winter, M. G. (1997). Use and application of the mca with particular reference to glacial tills, Transport Research Laboratory, TRL Rep. 273.
20. Sharma, N. K., Swain, S. K., & Sahoo U. C. (2012). Stabilization of a clayey soil with fly ash and lime: A micro level investigation” Geotechnical and Geological Engineering, 30, 1197-1205.