Investigation of Volumetric Deformation and Shear Strength Behavior of Sand-Bentonite Mixtures under High Temperature in the Presence of Perlite Additive

Öz

High temperature that occurs around energy structures and facilities affects the engineering behavior of soils. For that reason new materials or mixtures that will act as a barrier which resist to high temperatures are needed. In line with this requirement, "perlite", which is frequently used in thermal insulation in the construction industry, was added to the sand-bentonite mixture, which is currently used as a buffer material, to obtain a new mixture that is durable under high temperatures. In this study, compaction and consolidation tests of perlite-added sand-bentonite mixtures at room temperature, as well as direct shear tests at both room and high temperature (80°C) were conducted. As a result of the compaction test results, it was observed that the perlite additive decreased the dry unit weight of the sand-bentonite mixtures, while the optimum water content increased. It was determined that as the perlite content in the mixture increased, the total vertical deformation increased and the shear strength decreased with the addition of perlite both at room and at 80°C.

Anahtar Kelimeler

• Shear Strength
• Consolidation
• Sand-bentonite
• Perlite
• High Temperature

Kum-Bentonit Karışımlarının Hacimsel Deformasyon ve Yüksek Sıcaklık Altındaki Kayma Dayanımı Davranışının Perlit Katkısı Varlığında İncelenmesi

Öz

Enerji yapıları etrafında ortaya çıkan yüksek sıcaklığın zeminlerin mühendislik özelliklerini negatif yönde etkilemesi istenilmeyen bir durum olduğundan, bu alanlarda kullanılmak üzere yüksek sıcaklığa karşı bariyer görevi görecek yeni malzemelere ya da karışımlara ihtiyaç duyulmaktadır. Bu gereksinim doğrultusunda, inşaat sektöründe ısı yalıtımında kullanılan "perlit", halihazırda tampon malzeme olarak kullanılan kum-bentonit karışımına eklenerek yüksek sıcaklığa dayanıklı yeni bir karışım elde edilmesi amaçlanmıştır. Bu çalışmada perlit katkılı kum-bentonit karışımlarının oda sıcaklığı altında kompaksiyon, konsolidasyon deneyleri ve aynı zamanda hem oda (22~25°C) hem de yüksek sıcaklık altında (80°C) kesme kutusu deneyleri gerçekleştirilmiştir. Kompaksiyon deneylerinden elde edilen sonuçlara göre perlit katkısı kum-bentonit karışımlarının birim hacim ağırlık değerini azaltırken, optimum su içeriğini arttırmıştır. Karışımda perlit içeriği arttıkça toplam düşey deformasyonun arttığı ve kayma dayanımının hem oda hem de 80°C' sıcaklık altında perlit katkısı ile birlikte azaldığı belirlenmiştir.

Anahtar Kelimeler

• Kayma Dayanımı
• Konsolidasyon
• Kum-bentonit
• Perlit
• Yüksek Sıcaklık

Kaynakça

1. [1] Mitchell, J.K. 1969. Temperature Effects on the Engineering Properties and Behavior of Soils.Highway Research Board, Special Report 103, National Research Council, pp. 9-28.
2. [2] Wang, M.C., Benway, J.M. and Arayssi, A.M. 1990. The Effect of Heating on Engineering Properties of Clays," Physico-Chemical Aspects of Soil and Related Materials, ASTM STP 1095, K. B. Hoddinott and R. O. Lamb, Eds., American Society for Testing and Materials, Philadelphia, pp. 139-158.
3. [3] Day, D.E. 1965. Thermal Stabilization of Soils, Report 1, Technical Report No. 6-706, U.S. Army Engineers Waterways Experiment Station, Corps of Engineers, Vicksburg, MI.
4. [4] ]umikis, A.R. 1966. Thermal Soil Mechanics, Rutgers University Press, New Brunswick, NJ.
5. [5] Cekerevac C, Laloui L. 2004. Experimental study of thermal effects on the mechanical behaviour of a clay. Int J Numer Anal Methods Geomech. https://doi.org/10.1002/nag.332
6. [6] Hueckel, T., Baldi G. 1990. Thermoplasticity of saturated clays: Experimental constitutive study. J Geotech Eng. https://doi.org/10.1061/(ASCE)0733-9410(1990)116:12(1778)
7. [7] Karaman, S., Karaipekli, A., Sarı, A. and Bic, A. 2011. Polyethylene Glycol (PEG)/ Diatomite Composite as a Novel Form-Stable Phase Change Material for Thermal Energy Storage. Solar Energy Materials & Solar Cells. 95: 1647–53.
8. [8] Mekaddem, N., Ali S Ben, Fois, M., Hannachi A. 2019. Paraffin/expanded perlite/plaster as thermal energy storage composite. In: Energy Procedia.

9. [9] ASTM D6913/D6913M. 2017. Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis. ASTM Int. https://doi.org/10.1520/D06913-04
10. [10] ASTM:D854-14. 2014. Standard test methods for specific gravity of soil solids by water pycnometer. ASTM International, West Conshohocken, PA, USA, 1-8.
11. [11] ASTM:D4318-17e1. 2017. Standard test methods for liquid limit, plastic limit, and plasticity index of soils. ASTM International, West Conshohocken, PA, USA, 1-20.
12. [12] ASTM:D4972-18. 2018. Standard test methods for ph of soils. ASTM International, West Conshohocken, PA, USA, 1-6.
13. [13] ASTM:D698-12. 2012. Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort. ASTM Int. https://doi.org/10.1520/D0698-12.1.4
14. [14] ASTM International. 2011. ASTM D2435/D2435M-11: Standard Test Methods for One-Dimensional Consolidation Properties of Soils Using Incremental Loading. ASTM Int. https://doi.org/10.1520/D2435_D2435M-11
15. [15] ASTM International. 2011. D3080/D3080M-11. Standard test method for direct shear test of soils under consolidated drained conditions. ASTM Int. https://doi.org/10.1520/D3080
16. [16] Gu, K., Tang, C., Shi, B., Hong, J., Jin, F. 2014. A study of the effect of temperature on the structural strength of a clayey soil using a micropenetrometer. Bulletin of Engineering Geology and the Environment, 73, 747–58.
17. [17] Baldi, G., Hueckel T., Pellegrini R. 1988. Thermal volume changes of the mineral-water system in low-porosity clay soils. Can Geotech J. https://doi.org/10.1139/t88-089
18. [18] Romero, E., Gens A., Lloret A. 2001. Temperature effects on the hydraulic behaviour of an unsaturated clay. Geotech Geol Eng. https://doi.org/10.1023/A:1013133809333
19. [19] De Bruyn, D., Thimus, J.F. 1996. The influence of temperature on mechanical characteristics of Boom clay: the results of an initial laboratory programme. Engineering Geology 41, Nos. 1 – 4, 117 – 126.
20. [20] Kuntiwattanakul, P., Towhata, I., Ohishi, K. and Seko, I. 1995. Temperature eŠects on undrained shear characteristics of clay, Soils and Foundations ,35(1), 147–162.