Document Type : Original Research Paper
Authors
1 Faculty of Garmsar, Amirkabir University of Technology, Tehran, Iran
2 Faculty of Civil and Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
3 Faculty of Mining Engineering., Amirkabir University of Technology, Tehran, Iran
Abstract
The present study delves into investigating the impact of sample size and geometry on the mechanical behavior of rock and concrete. More specifically, it examines factors including Uniaxial Compressive Strength (UCS), Elastic Modulus (E), and Pressure Wave Velocity (Vp). Results indicated a notable correlation between the dimensions and morphology of the specimens with these properties. All tests were conducted at a uniform loading rate of 0.002 mm/s. According to the outcomes, the effect of sample size and shape on UCS for concrete is more predictable than for rock. The increase in the sample size led to an initial increase followed by a decline in the UCS values of the rocks. Furthermore, the concrete typically showed a drop in the UCS values as sample size increased. The UCS and E values rose at first before falling, suggesting the existence of a sample size with maximum UCS. The Vp values of the prismatic rock and concrete samples continually grew. After attaining their optimum strength, the prismatic samples showed greater degrees of flexibility and ductility compared to cylindrical ones because of post peak behavior. This suggests that prismatic samples, with their less slender geometry and reduced tendency for brittle behavior, are deemed more suitable for UCS testing. These results can improve the accuracy of assessing the mechanical properties of tunneling materials, particularly those used in subsurface construction in urban roads and highways.
Keywords
- Shape and size effect
- Uniaxial compressive strength
- Elastic modulus
- Pressure wave velocity
- Brittle and Ductile materials
Main Subjects
[1]. Li, M., Hao, H., Shi, Y., & Hao, Y. (2018). Specimen shape and size effects on the concrete compressive strength under static and dynamic tests. Construction and Building Materials, 161, 84-93.
[2]. Feng, F., Li, X., Rostami, J., Peng, D., Li, D., & Du, K. (2019). Numerical investigation of hard rock strength and fracturing under polyaxial compression based on Mogi-Coulomb failure criterion. International Journal of Geomechanics, 19(4).
[3]. Mohammadifar, M., Asheghi M.T., & Fahimifar, A. (2024). Parametric and Sensitivity Analysis on the Effects of Geotechnical Parameters on Tunnel Lining in Soil Surrounding. Journal of Structural and Construction Engineering (JSCE).
[4]. Kazempour, O., Moosazadeh, S., Qarahasanlou, A.N., & Baghban G.M.R. (2024). Urban Tunneling Risk Management: Ground Settlement Assessment through Proportional Hazards Modeling. Journal of Mining and Environment, 15(3), 1161-1175.
[5]. Khalili, S., Monjezi, M., Amini, K.H., & Saghat forosh, A. (2024). Evaluation the Effect of Blast Pattern on Post-Failure Rate around the Miyaneh-Ardabil Railway Tunnel. Journal of Mining and Environment, 15(3), 1149-1160.
[6]. Mohammadifar, M., Asheghi Mehmandari, T., & Mirjafari, SA. (2024). Discovering the optimal distance between spatial orthogonal tunnels: A dynamic analysis using Tehran metro as a case study. Insight - Civil Engineering. 2024; 7(1): 613.
[7]. Mogi, K. (1966). Some presice measurements of fracture strength of rocks under uniform compressive stress. Felsmech, Ingenieurgeol, 4(1), 41.
[8]. Obert, L., & Duvall, W.I. (1967). Rock mechanics and the design of structures in rock. John Wiley & Sons, Inc.
[9]. John, M. (1972). The Influence of Length to Diameter Ratio on Rock Properties in Uniaxial Compression, A Contribution to Standardization in Rock Mechanics Testing; Report South African CSIR No ME1083/5, Council for Scientific and Industrial Research, Pretoria, South Africa. Int J Rock Mech Min Sci, 438, 12771287.
[10]. Labuz, J.F., & Bridell, J. (1993). Reducing frictional constraint in compression testing through lubrication. International journal of rock mechanics and mining sciences & geomechanics abstracts, 30(4), 451-455.
[11]. Mogi, K. (2006). Experimental rock mechanics. The Netherlands, Taylor and Francis Balkema.
[12]. Pan, P.Z., Feng, X.T., & Hudson, J.A. (2009). Study of failure and scale effects in rocks under uniaxial compression using 3D cellular automata. International Journal of Rock Mechanics and Mining Sciences, 46(4), 674-685.
[13]. Omidi Manesh, M., Sarfarazi, V., Babanouri, N., & Rezaei, A. (2023) Investigation of External Work, Fracture Energy, and Fracture Toughness of Oil Well Cement Sheath using HCCD Test and CSTBD Test. Journal of Mining and Environment, 14(2), 619-634.
[14]. Omidi Manesh, M., Sarfarazi, V., Babanouri, N., & Rezaei, A. (2023) Investigation of Fracture Toughness of Shotcrete using Semi-Circular Bend Test and Notched Brazilian Disc test; Experimental Test and Numerical Approach. Journal of Mining and Environment, 14(1), 233-242.
[15]. Yavari, M.D., Haeri, H., Sarfarazi, V., Fatehi Marji, M., & Lazemi H.A. (2021) On Propagation Mechanism of Cracks Emanating from Two Neighboring Holes in Cubic Concrete Specimens under Various Lateral Confinements. Journal of Mining and Environment, 12(4), 1003-1017.
[16]. ASTM, D7012-14. (2004). Standard Test Methods for Compressive Strength and Elastic Moduli of Intact Rock Core Specimens under Varying States of Stress and Temperatures. ASTM, West Conshohocken, PA, USA.
[17]. Hudson, J.A., Crouch, S.L., & Fairhurst, C. (1972). Crouch, and C. Fairhurst, Soft, stiff and servo-controlled testing machines: a review with reference to rock failure. Engineering Geology, 6(3), 155-189.
[18]. Thuro, K., Plinninger, R., Zäh, S., & Schütz, S. (2001). Scale effects in rock strength properties, Part 1: Unconfined compressive test and Brazilian test. ISRM regional symposium, EUROCK.
[19]. Tuncay, E., & Hasancebi, N. (2009). The effect of length to diameter ratio of test specimens on the uniaxial compressive strength of rock. Bulletin of engineering geology and the environment, 68, 491-497.
[20]. Liang, C., Zhang, Q., Li, X., & Xin, P. (2016). The effect of specimen shape and strain rate on uniaxial compressive behavior of rock material. Bulletin of Engineering Geology and the Environment, 75, 1669-1681.
[21]. ASTM, C170/C170M-09. (2009). Standard Test Method for Compressive Strength of Dimension Stone. ASTM, West Conshohocken, PA, USA.
[22]. Du, K., Su, R., Tao, M., Yang, C., Momeni, A., & Wang, S. (2019). Specimen shape and cross-section effects on the mechanical properties of rocks under uniaxial compressive stress. Bulletin of Engineering Geology and the Environment, 78, 6061-6074.
[23]. Naseri, A., Ghasemi, O., Asghari, A., Fahimifar, A., & Havaei, G. (2023). Influence of Geometry (Size and Shape) on the Correlation Between Strength Properties and Point Load Strength Index of Brittle Materials. 13th International Congress on Civil Engineering, University of Science and Technology, Tehran, Iran.
[24]. Li, D., Li, C.C., & Li, X. (2011). Influence of sample height-to-width ratios on failure mode for rectangular prism samples of hard rock loaded in uniaxial compression. Rock Mechanics and Rock Engineering, 44, 253-267.
[25]. Asheghi Mehmandari, T., Mohammadi, D., Ahmadi, M. & Mohammadifar, M. (2024) Fracture mechanism and ductility performances of fiber reinforced shotcrete under flexural loading insights from digital image correlation (DIC). Insight - Civil Engineering. 2024; 7(1): 611.
[26]. Du, K., Tao, M., Li, X., & Zhou, J. (2016). Experimental study of slabbing and rockburst induced by true-triaxial unloading and local dynamic disturbance. Rock Mechanics and Rock Engineering, 49, 3437-3453.
[27]. Hoek, E. (2000). Practical rock engineering, Course notes by Evert Hoek. AA Balkema Publishers, Rotterdam, Netherlands.
[28]. Kong, X., Liu, Q., & Lu, H. (2021). Effects of rock specimen size on mechanical properties in laboratory testing. Journal of Geotechnical and Geoenvironmental Engineering, 147(5), 04021013.
[29]. Asheghi Mehmandari, T. & Alizadeh, H. (2023). Engineering Concept and Construction Methods of High-Rise Building. Sanei Publisher,Tehran, 308 P.
[30]. Hudyma, N., Avar, B.B., & Karakouzian, M. (2004). Compressive strength and failure modes of lithophysae-rich Topopah Spring Tuff specimens and analog models containing cavities. Engineering Geology, 73(1-2), 179-190.
[31]. Puppala, A.J., Hudyma, N., & Likos, W.J. (2007). Problematic Soils and Rocks and In Situ Characterization. American Society of Civil Engineers.
[32]. Meng, Q., Zhang, M., Han, L., Pu, H., & Li, H. (2016). Effects of size and strain rate on the mechanical behaviors of rock specimens under uniaxial compression. Arabian Journal of Geosciences, 9, 1-14.
[33]. Yuki, N., Aoto, S., Ogata, Y., & Yoshinaka, R. (1995). The scale and creep effects on strength of welded tuff. Rock foundation, 219-222.
[34]. Zare, P., Asheghi, M.T., Fahimifar, A., & Zabetian, S. (2020). Experimental Assessment of Damage and Crack Propagation Mechanism in Heterogeneous Rocks. 5th International Conference on Applied Research in Science and Engineering, University of Amsterdam, Netherlands.
[35]. Kahraman, S. (2001). Evaluation of simple methods for assessing the uniaxial compressive strength of rock. International Journal of Rock Mechanics and Mining Sciences, 38(7), 981-994.
[36]. Yasar, E., & Erdogan, Y. (2004). Correlating sound velocity with the density, compressive strength and Young's modulus of carbonate rocks. International Journal of Rock Mechanics and Mining Sciences, 41(5), 871-875.
[37]. Sharma, P., & Singh, T. (2008). correlation between P-wave velocity, impact strength index, slake durability index and uniaxial compressive strength. Bulletin of Engineering Geology and the Environment, 67, 17-22.
[38]. Yagiz, S. (2009). Predicting uniaxial compressive strength, modulus of elasticity and index properties of rocks using the Schmidt hammer. Bulletin of engineering geology and the environment, 68, 55-63.
[39]. Diamantis, K., Bellas, S., Migiros, G., & Gartzos, E. (2011). Correlating wave velocities with physical, mechanical properties and petrographic characteristics of peridotites from the central Greece. Geotechnical and Geological Engineering, 29, 1049-1062.
[40]. Yagiz, S. (2011). P-wave velocity test for assessment of geotechnical properties of some rock materials. Bulletin of Materials Science, 34, 947-953.
[41]. Sarkar, K., Vishal, V., & Singh, T. (2012). An empirical correlation of index geomechanical parameters with the compressional wave velocity. Geotechnical and Geological Engineering, 30, 469-479.
[42]. Asheghi, M.T., Fahimifar, A., & Asemi, F. (2020). The Effect of the Crack Initiation and Propagation on the P-Wave Velocity of Limestone and Plaster Subjected to Compressive Loading. AUT Journal of Civil Engineering, 4(1), 55-62.
[43]. Jamshidi, A., Nikudel, M.R., Khamehchiyan, M., & Sahamieh, R.Z. (2016). The effect of specimen diameter size on uniaxial compressive strength, P-wave velocity and the correlation between them. Geomechanics and Geoengineering, 11(1), 13-19.
[44]. Masoumi, H., Saydam, S., & Hagan, P.C. (2016). Unified size-effect law for intact rock. International Journal of Geomechanics, 16(2), 04015059.
[45]. Hawkins, A. (1998). Aspects of rock strength. Bulletin of Engineering Geology and the Environment, 57, 17-30.
[46]. Jackson, R., & Lau, J. (1990). The effect of specimen size on the laboratory mechanical properties of Lac du Bonnet grey granite. International workshop on scale effects in rock masses.
[47]. Natau, O.P., Frohlich, B.O., & Mutschler, T.O. (1983). Recent developments of the large scale triaxial test. 5th ISRM Congress.
[48]. Herget, G., & Unrug, K. (1974). In-situ strength prediction of mine pillars based on laboratory tests. 3rd Congress of the Int, Society for Rock Mechanics.
[49]. Hoskins, J.R., & Horino, F.G. (1969). Influence of Spherical Head Size and Specimen Diameters on the Uniaxial Compressive Strength of Rocks. Department of the Interior, Bureau of Mines, United State.
[50]. Nishimatsu, Y., Yamaguchi, U., Motosugi, K., & Morita, M. (1969). The size effect and experimental error of the strength of rocks. J Min Mat Proc Inst Jpn, 18, 1019-1025.
[51]. Lundborg, N. (1967). The strength-size relation of granite. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 4(3), 269-272.
[52]. Jahns, H. (1966). Measuring the strength of rock in situ at an increasing scale. ISRM Congress.
[53]. ASTM, C136-01. (2001). Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates. ASTM, West Conshohocken, PA, USA.
[54]. Mehmandari, T.A., Shokouhian, M., Imani, M., & Fahimifar, A. (2024). Experimental and numerical analysis of tunnel primary support using recycled, and hybrid fiber reinforced shotcrete. Structures, Elsevier, 63, 106282.
[55]. ASTM, C191–08. (2008). Standard Test Methods for Time of Setting of Hydraulic Cement by Vicat Needle. ASTM, West Conshohocken, PA, USA.
[56]. ASTM, C109/C109M-20. (2008). Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens). ASTM, West Conshohocken, PA, USA.
[57]. ASTM, C188–95. (2003). Standard Test Method for Density of Hydraulic Cement. ASTM, West Conshohocken, PA, USA.
[58]. ASTM, D2845–00. (2000). Standard Test Method for Laboratory Determination of Pulse Velocities and Ultrasonic Elastic Constants of Rock. ASTM, West Conshohocken, PA, USA.
[59]. Xu, Y., & Cai, M. (2017). Numerical study on the influence of cross-sectional shape on strength and deformation behaviors of rocks under uniaxial compression. Computers and Geotechnics, 84, 129-137.
[60]. Naseri, A., Fattahi, S.M., Shokri, F., Hosseinnia, A., & Fahimifar, A. (2024). Exploring the Influence of Sample Geometry on the Tensile Strength of Rock and Concrete: An Integrated Experimental and Numerical Analysis. Iranian Journal of Science and Technology, Transactions of Civil Engineering.
[61]. ASTM, D2938-95. (2002). Standard test method for unconfined compressive strength of intact rock core specimens. ASTM, West Conshohocken, PA, USA.
[62]. Zhang, C., Lin, H., Qiu, C., Jiang, T., & Zhang, J. (2020). The effect of cross-section shape on deformation, damage and failure of rock-like materials under uniaxial compression from both a macro and micro viewpoint. International Journal of Damage Mechanics, 29(7), 1076-1099.
[63]. Mehta, P.K., & Monteiro, P. (2006). Concrete: microstructure, properties, and materials. McGraw Hill.
[64]. Darlington, W.J., Ranjith, P.G., & Choi, S. (2011). The effect of specimen size on strength and other properties in laboratory testing of rock and rock-like cementitious brittle materials. Rock mechanics and rock engineering, 44, 513-529.
[65]. Tatiana, D., Martin, B., Petra, D., & Renáta, A. (2022). Influence of specimen size and shape on the uniaxial compressive strength values of selected Western Carpathians rocks. Environmental Earth Sciences, 81(9).
[66]. Usoltseva, O.M., & Tsoi, P.A. (2021). The Influence of Size Effect on Strength and Deformation Characteristics of Different Types of Rock Samples. International science and technology conference Earth science, Vladivostok, Russian Federation.
[67]. Fener, M. (2011). The effect of rock sample dimension on the P-wave velocity. Journal of Nondestructive Evaluation, 30, 99-105.
[68]. Li, H., Song, K., Tang, M., Qin, M., Liu, Z., Qu, M., Li, B., & Li, Y. (2021). Determination of scale effects on mechanical properties of Berea Sandstone. Geofluids, 1-12.
)