Thermal Shock Effect on Strength Loss Properties of Rock Materials: An Experimental Study on Thermal Fatigue Durability

Four different types of rock materials from Eastern Black Sea Region of Turkey were investigated to determine their change in porosity as well as the degree of cracking, fracturing, disintegration and strength loss under heating-cooling cycles with variations in temperatures up to 300 Co . Cooling time and thermal strains of the rock specimens were also determined in this study. Totally, sixty rock core samples were tested to evaluate their physico-mechanical and mechanical properties. Thermal cycling was found to lead for increase in the porosity of the rocks, making new cracks, particle disintegration for two types of tested rocks and considerable losses in uniaxial compressive strength values of all the rock materials tested in this study. The purpose of this study is to investigate immediate changes in temperature values rather than step by step heating up to a target temperature. For instance, rock samples were directly put in 250 oC stove from a -50 oC cabin in the last and fifth thermal cycling. After the heating process, specimens were cooled in water and air. This study aims to be a usable reference to establish a thermal change procedure and improve a new testing method for determination of thermal fatigue durability of rock materials.

Termal Şok Etkisinin Kaya Malzemelerinin Dayanım Kaybı Özellikleri üzerindeki Etkileri: Termal Yorulma üzerine Deneysel bir Çalışma

Doğu Karadeniz bölgesinden dört farklı kaya malzemesinin, 300 oC’ye kadar değişen sıcaklık değişimlerine sahip termal döngüler altında porozite değerlerindeki değişim, çatlama, parçalanma ve dayanım kaybı özellikleri incelenmiştir. Numunelerin soğuma süreleri ve soğuma esnasındaki birim deformasyonları da bu çalışma kapsamında belirlenmiştir. Toplamda altmış adet karot numunesi test edilmiştir. Elde edilen sonuçlara göre, döngü sayısı arttıkça porozite değerlerinde artış, dayanım değerlerinde düşüş yaşanmakta olduğu, kaya malzemesi türüne bağlı olarak çatlamalar ve parça kopmaları şeklinde bozunmaların olabildiği görülmüştür. Çalışmadaki termal döngülerde ani sıcaklık değişimleri incelenmiştir. Örneğin, beşinci ve son döngüde numuneler 250 oC etüvden alınarak doğrudan -50 oC sıcaklıktaki soğutma kabinine alınmıştır. Isıtma işleminden sonra numuneler suda ve havada farklı ortamlarda soğutulmuşlardır. Bu çalışma, kaya malzemelerinin termal yorulma karşısındaki dirençlerinin değerlendirilmesi üzerine ısıtma-soğutma işlemleri prosedürün belirlenmesi ve geliştirilecek yeni bir metoda yönelik çalışmalara kullanışlı bir referans oluşturmayı amaçlamıştır.

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Akbay D., Koççaz C.E., Altındağ R., Uğur İ., Varol M., (2014), Doğal Taşların Nokta Yük Dayanım İndeks Değerlerinin Sıcaklık Etkisine Bağlı Olarak Değişimi, XI. Bölgesel Kaya Mekaniği Sempozyumu, KAYAMEK’2014, Afyonkarahisar, Türkiye, ss. 381- 389.

Brotons V., Tomas R., Ivorra S., Alarcon J.C., (2013), Temperature influence on the physical and mechanical properties of a porous rock: San Julian's calcarenite, Engineering Geology, 167, 117-127.

Browning J., Meredith P., Gudmundsson A., (2016), Cooling dominated cracking in thermally stressed volcanic rocks, Geophysical Research Letters, 43, 8417–8425.

Cai C., Li G., Huang Z., Tian S., Shen Z., Fu X., (2015), Experiment of coal damage due to super-cooling with liquid nitrogen, Journal of Natural Gas Science and Engineering, 22, 42-48.

Hall K., (1999), The role of thermal stress fatigue in the breakdown of rock in cold regions, Geomorphology, 31, 47-63.

Huang S., Xia K., (2015), Effect of heat-treatment on the dynamic compressive strength of Longyou sandstone, Engineering Geology, 191, 1-7.

Isaka, B.L.A., Gamage R.P., Rathnaweera T.D., Perera M.S.A., Chandrasekharam D., Kumari W.G.P., (2018), An Influence of Thermally-Induced Micro-Cracking under Cooling Treatments: Mechanical Characteristics of Australian Granite, Energies, 11, 1338, doi: 10.3390/en11061338.

ISRM, (2007), The blue book - the complete ISRM suggested methods for rock characterisation, testing and monitoring: 1974-2006

(Ed.: Ulusay R., Hudson J.A.), Turkish National Group of ISRM, Ankara.

Keshavarz, M., Pellet F.L., Loret B., (2010), Damage and Changes in Mechanical Properties of a Gabbro Thermally Loaded up to 1,000 oC, Pure and Applied Geophysics, 167, 1511–1523.

Kim K., Kemeny J., Nickerson M., (2014), Effect of Rapid Thermal Cooling on Mechanical Rock Properties, Rock Mechanics and Rock Engineering, 47, 2005–2019.

Komurlu E., Kesimal A., (2013), Tunnelling and Support Materials from Past to Present, The Journal of The Chamber of Mining Engineers of Turkey, 52, 33-47.

Komurlu E., Kesimal A., (2015), Experimental study of polyurethane foam reinforced soil used as a rock-like material, Journal of Rock Mechanics and Geotechnical Engineering, 7(5), 566-572.

Kumari, W.G.P., Ranjith P.G., Perera M.S.A., Chen B.K., Abdulagatov I.M., (2017), Temperature-dependent mechanical behaviour of Australian Strathbogie granite with different cooling treatments, Engineering Geology, 229, 31-44.

Lafdi K., Mesalhy O., Shaikh S., (2007), Experimental study on the influence of foam porosity and pore size on the melting of phase change materials, Journal of Applied Physics, 102, 083549, doi: 10.1063/1.2802183.

Lin V., (2002), Permanent strain of thermal expansion and thermally induced microcracking in Inada granite, Journal of Geophysical Research, 107, B10, 2215, doi: 10.1029/2001JB000648.

Mahmutoglu Y., (1998), Mechanical Behaviour of Cyclically Heated Fine Grained Rock, Rock Mechanics and Rock Engineering, 31, 169-179.

Mahmutoglu Y., (2006), The effects of strain rate and saturation on a micro-cracked marble, Engineering Geology, 82, 137-144.

Mahmutoglu Y., (2017), Prediction of weathering by thermal degradation of a coarse-grained marble using ultrasonic pulse velocity, Environmental Earth Sciences, 76, 435, DOI 10.1007/s12665-017-6770-y.

Papay Z., Török A., (2018), Effect of Thermal and Freeze-thaw Stress on the Mechanical Properties of Porous Limestone, Periodica Polytechnica Civil Engineering, 62(2), 423-428.

Papitha R., Suresh M.B., Das, D., Johnson R., (2013), Effect of micro-cracking on the thermal conductivity and thermal expansion of tialite (Al2TiO5) ceramics, Processing and Application of Ceramics, 7(3), 143–146.

Sandström G.E., (1963), The History of Tunnelling, Barrie Books Ltd., Great Britain, 427ss.

Sousa L.M.O., Rio L.M.S., Calleja L., Argandona V.G.R., Rey A.R. (2005), Influence of microfractures and porosity on the physicomechanical properties and weathering of ornamental granites, Engineering Geology, 77, 153-168.

Sun Q., Lü C., Cao L., Li W., Geng J., Zhnag W., (2016), Thermal properties of sand stone after treatment at high temperature, International Journal of Rock Mechanics & Mining Sciences, 85, 60–66.

Sundarram S.S., Li W., (2014), The Effect of Pore Size and Porosity on Thermal Management Performance of Phase Change Material Infiltrated Microcellular Metal Foams, Applied Thermal Engineering, 64, 147-154.

Sygała A., Bukowska M., Janoszek T., (2013), High Temperature Versus Geomechanical Parameters of Selected Rocks – The Present State of Research, Journal of Sustainable Mining, 12(4), 45–51.

Török A., Török A., (2015), The effect of temperature on the strength of two different granites, Central European Geology, 58/4, 356– 369.

Vargas E.A., Velloso R.Q., Chavez L.E., Gusmao L., Amaral C.P., (2013), On the Effect of Thermally Induced Stresses in Failures of Some Rock Slopes in Rio de Janeiro, Brazil, Rock Mechanics and Rock Engineering, 46, 123–134.

Wang L., Rhee H., Felicelli S.D., Sabau A.S., Berry J.T., (2009), Interdependence Between Cooling Rate, Microstructure and Porosity In Mg Alloy AE42, In: Magnesium Technology 2009 (Ed. by Nyberg E.A., Agnew S.R., Neelameggham N.R., Pekguleryuz M.O.), The Minerals, Metals & Materials Society, United States.

Wang Z., Hao S., (2017), Study on Dynamic Compressive Mechanical Properties and Failure Modes of Heat-Treated Granite, Latin American Journal of Solids and Structures, 14, 657-673.

West G., (1988), Innovation and the Rise of the Tunnelling History, Cambridge University Press, Cambridge, 355ss.

Yang S., Ranjith P.G., Jing H., Tian W., Ju Y., (2017), An experimental investigation on thermal damage and failure mechanical behavior of granite after exposure to different high temperature treatments, Geothermics, 65, 180-197.

Zhang C., Wang L., Du J., (2015), Numerical modelling rock deformation subject to nitrogen cooling to study permeability evolution, International Journal of Coal Science and Technology, 2, 293-298.

Zhang F., Zhao J., Hu D., Skoczylas F., Shao J., (2018), Laboratory Investigation on Physical and Mechanical Properties of Granite After Heating and Water‑ Cooling Treatment, Rock Mechanics and Rock Engineering, 51, 677–694.

Zhao Z., Liu Z., Pu H., Li X., (2018), Effect of Thermal Treatment on Brazilian Tensile Strength of Granites with Different Grain Size Distributions, Rock Mechanics and Rock Engineering, 51, 1293–1303.