Abstract
Hardness is one of the critical physical characteristics of minerals and rocks, which indicates the resistance of the rock to penetration, scratch, or permanent deformation. As a basic concept, rock hardness has a significant role in rock mechanics and geological engineering and is an appropriate diagnostic tool for the classification of minerals and rocks. The main purpose of this study is to guide rock engineers to measure the rock hardness faster, easier, and more accurately using Leeb’s dynamic hardness test. Accordingly, this paper presents a new rock hardness classification system based on the Leeb dynamic and portable hardness testing method. It is a well-known method for its fast and straightforward procedure testing equipment. A set of 33 different rock types were collected and tested during this study. Next, in-depth microscopic mineralogical studies were performed to determine the precise Mohs hardness value. The Mohs hardness was considered the leading hardness benchmark during the experimental studies, and the Leeb hardness was adopted to classify based on this hardness. A series of laboratory studies and statistical analysis was performed to predict the Shore and Vickers hardness using Leeb hardness. Finally, based on the comparative studies, it is recommended to classify the rocks considering the Leeb hardness method in six different categories: extremely soft (1–250), soft (250–450), moderately soft (450–750), moderately hard (750–850), hard (850–920), and extremely hard (920–1000). The provided classification could be useful in a vast range of rock engineering applications, especially for feasibility studies of rock engineering projects and engineering geology.
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References
Ajalloeian R, Jamshidi A, Khorasani R (2020) Evaluating the effects of mineral grain size and mineralogical composition on the correlated equations between strength and Schmidt hardness of granitic rocks. Geotech Geol Eng 1–11. https://doi.org/10.1007/s10706-020-01321-6
Aladejare AE (2020) Evaluation of empirical estimation of uniaxial compressive strength of rock using measurements from index and physical tests. J Rock Mech Geotech Eng 12:256–268. https://doi.org/10.1016/j.jrmge.2019.08.001
Alberti AP, Gomes A, Trenhaile A et al (2013) Correlating river terrace remnants using an Equotip hardness tester: an example from the Miño River, northwestern Iberian Peninsula. Geomorphology 192:59–70. https://doi.org/10.1016/j.geomorph.2013.03.017
Aligholi S, Lashkaripour GR, Ghafoori M (2017) Strength/brittleness classification of igneous intact rocks based on basic physical and dynamic properties. Rock Mech Rock Eng 50:45–65. https://doi.org/10.1007/s00603-016-1106-x
Altindag R, Güney A (2006) ISRM Suggested Method for determining the Shore Hardness value for rock. Int J Rock Mech Min Sci 43:19–22. https://doi.org/10.1016/j.ijrmms.2005.04.004
Aoki H, Matsukura Y (2007) A new technique for non-destructive field measurement of rock-surface strength: an application of the Equotip hardness tester to weathering studies. Earth Surface Processes and Landforms: the Journal of the British Geomorphological Research Group 32:1759–1769. https://doi.org/10.1002/esp.1492
ASTM A956–06 (2006) Standard test method for Leeb hardness testing of steel products. West Conshohocken, PA
Aydin A, Basu A (2005) The Schmidt hammer in rock material characterization. Eng Geol 81:1–14. https://doi.org/10.1016/j.enggeo.2005.06.006
Aydin G, Karakurt I, Aydiner K (2013) Investigation of the surface roughness of rocks sawn by diamond sawblades. Int J Rock Mech Min Sci 61:171–182. https://doi.org/10.1016/j.ijrmms.2013.03.002
Basarir H, Karpuz C (2004) A rippability classification system for marls in lignite mines. Eng Geol 74:303–318. https://doi.org/10.1016/j.enggeo.2004.04.004
Bell FG, Lindsay P (1999) The petrographic and geomechanical properties of some sandstones from the Newspaper Member of the Natal Group near Durban, South Africa. Eng Geol 53:57–81. https://doi.org/10.1016/S0013-7952(98)00081-7
Bieniawski ZT (1989) Engineering rock mass classifications: a complete manual for engineers and geologists in mining, civil, and petroleum engineering. John Wiley & Sons, New York
Bilgin N, Phillips HR, Yavuz N (1992) The cuttability classification of coal seams and an example to a mechanical plough application in ELI Darkale Coal Mine. In: Proceedings of the 8th coal congress of Turkey, Zonguldak,. pp 31–53
Çelik SB, Çobanoğlu İ (2019) Comparative investigation of Shore, Schmidt, and Leeb hardness tests in the characterization of rock materials. Environ Earth Sci 78:554. https://doi.org/10.1007/s12665-019-8567-7
Coombes MA, Feal-Pérez A, Naylor LA, Wilhelm K (2013) A non-destructive tool for detecting changes in the hardness of engineering materials: application of the Equotip durometer in the coastal zone. Eng Geol 167:14–19. https://doi.org/10.1016/j.enggeo.2013.10.003
Corkum AG, Asiri Y, El Naggar H, Kinakin D (2018) The Leeb hardness test for rock: an updated methodology and UCS correlation. Rock Mech Rock Eng 51:665–675. https://doi.org/10.1007/s00603-017-1372-2
Demirdag S, Yavuz H, Altindag R (2009) The effect of sample size on Schmidt rebound hardness value of rocks. Int J Rock Mech Min Sci 46:725–730. https://doi.org/10.1016/j.ijrmms.2008.09.004
Desarnaud J, Kiriyama K, Bicer Simsir B et al (2019) A laboratory study of Equotip surface hardness measurements on a range of sandstones: what influences the values and what do they mean?. Earth Surf Proc Land 44:1419–1429. https://doi.org/10.1002/esp.4584
Freire-Lista DM, Fort R (2017) Exfoliation microcracks in building granite. Implications for Anisotropy Engineering Geology 220:85–93. https://doi.org/10.1016/j.enggeo.2017.01.027
Freire-Lista DM, Fort R, Varas-Muriel MJ (2016) Thermal stress-induced microcracking in building granite. Eng Geol 206:83–93. https://doi.org/10.1016/j.enggeo.2016.03.005
Ghorbani S, Hoseinie SH, Ghasemi E, Sherizadeh T (2022) Application of Leeb hardness test in prediction of dynamic elastic constants of sedimentary and igneous rocks. Geotech Geol Eng 1–21. https://doi.org/10.1007/s10706-022-02083-z
Goel RK, Singh B (2011) Engineering rock mass classification: tunnelling, foundations and landslides. Edinburgh: Butterworth-Heinemann/Elsevier
Gokhale BV (2010) Rotary drilling and blasting in large surface mines. CRC Press
Gomez-Heras M, Benavente D, Pla C et al (2020) Ultrasonic pulse velocity as a way of improving uniaxial compressive strength estimations from Leeb hardness measurements. Constr Build Mater 261:119996. https://doi.org/10.1016/j.conbuildmat.2020.119996
Hassanpour J (2018) Development of an empirical model to estimate disc cutter wear for sedimentary and low to medium grade metamorphic rocks. Tunn Undergr Space Technol 75:90–99. https://doi.org/10.1016/j.tust.2018.02.009
Heiniö M (1999) Rock Excavation Handbook. Sandvik Tamrock Corp, [s.l., Sweden]
Holmgeirsdottir TH, Thomas PR (1998) Use of the D-762 shore hardness scleroscope for testing small rock volumes. Int J Rock Mech Min Sci 35:85–92. https://doi.org/10.1016/S0148-9062(97)00317-3
Hoseinie SH, Aghababaei H, Pourrahimian Y (2008) Development of a new classification system for assessing of rock mass drillability index (RDi). Int J Rock Mech Min Sci 45:1–10. https://doi.org/10.1016/j.ijrmms.2007.04.001
Hoseinie SH, Ataei M, Mikaeil R (2019) Effects of microfabric on drillability of rocks. Bull Eng Geol Env 78:1443–1449. https://doi.org/10.1007/s10064-017-1188-z
Hoseinie SH, Ataei M, Mikaiel R (2012) Comparison of some rock hardness scales applied in drillability studies. Arab J Sci Eng 37:1451–1458. https://doi.org/10.1007/s13369-012-0247-9
Hoseinie SH, Ataei M, Osanloo M (2009) A new classification system for evaluating rock penetrability. Int J Rock Mech Min Sci 46:1329–1340. https://doi.org/10.1016/j.ijrmms.2009.07.002
Jamshidi A, Zamanian H, Sahamieh RZ (2018) The effect of density and porosity on the correlation between uniaxial compressive strength and P-wave velocity. Rock Mech Rock Eng 51:1279–1286
Jimeno EL, Jimino CL, Carcedo A (1995) Drilling and blasting of rocks. CRC Press
Kahraman S, Gunaydin O (2008) Indentation hardness test to estimate the sawability of carbonate rocks. Bull Eng Geol Env 67:507–511. https://doi.org/10.1007/s10064-008-0162-1
Kamani M, Ajalloeian R (2019) Evaluation of engineering properties of some carbonate rocks trough corrected texture coefficient. Geotech Geol Eng 37:599–614. https://doi.org/10.1007/s10706-018-0630-8
Karpuz C (1990) A classification system for excavation of surface coal measures. Min Sci Technol 11:157–163. https://doi.org/10.1016/0167-9031(90)90303-A
Kompatscher M (2004) Equotip-rebound hardness testing after D. Leeb. In: Proceedings, Conference on Hardness Measurements Theory and Application in Laboratories and Industries. Citeseer, pp 1–12
Leeb D (1978) New dynamic method for hardness testing of metallic materials. Rev Metal 15:123–128
Mol L (2014) Measuring rock hardness in the field. In: Clarke, Lucy and Nield J eds. (ed) Geomorphological Techniques, Geomorphol. British Society for Geomorphology
Moses C, Robinson D, Barlow J (2014) Methods for measuring rock surface weathering and erosion: a critical review. Earth Sci Rev 135:141–161. https://doi.org/10.1016/j.earscirev.2014.04.006
Sajid M, Coggan J, Arif M et al (2016) Petrographic features as an effective indicator for the variation in strength of granites. Eng Geol 202:44–54. https://doi.org/10.1016/j.enggeo.2016.01.001
Saotome A, Yoshinaka R, Osada M, Sugiyama H (2002) Constituent material properties and clast-size distribution of volcanic breccia. Eng Geol 64:1–17. https://doi.org/10.1016/S0013-7952(01)00083-7
Shalabi FI, Cording EJ, Al-Hattamleh OH (2007) Estimation of rock engineering properties using hardness tests. Eng Geol 90:138–147. https://doi.org/10.1016/j.enggeo.2006.12.006
Smith RL, Sandly GE (1922) An accurate method of determining the hardness of metals, with particular reference to those of a high degree of hardness. Proc Inst Mech Eng 102:623–641. https://doi.org/10.1243/pime_proc_1922_102_033_02
Ulusay R, Erguler ZA (2012) Needle penetration test: evaluation of its performance and possible uses in predicting strength of weak and soft rocks. Eng Geol 149:47–56. https://doi.org/10.1016/j.enggeo.2012.08.007
Verhoef PNW (1997) Wear of rock cutting tools: implications for the site investigation of rock dredging projects. Balkema, Rotterdam
Verwaal W, Mulder A (1993) Estimating rock strength with the Equotip hardness tester. Int J Rock Mech Min Sci Geomech Abstr 30:659–662. https://doi.org/10.1016/0148-9062(93)91226-9
Viles H, Goudie A, Grab S, Lalley J (2011) The use of the Schmidt Hammer and Equotip for rock hardness assessment in geomorphology and heritage science: a comparative analysis. Earth Surf Proc Land 36:320–333. https://doi.org/10.1002/esp.2040
Winkler EM (2013) Stone: properties, durability in man’s environment, 2nd edn. Springer, Vienna
**e J, Tamaki J (2007) Parameterization of micro-hardness distribution in granite related to abrasive machining performance. J Mater Process Technol 186:253–258. https://doi.org/10.1016/j.jmatprotec.2006.12.041
Yılmaz NG (2011) Abrasivity assessment of granitic building stones in relation to diamond tool wear rate using mineralogy-based rock hardness indexes. Rock Mech Rock Eng 44:725. https://doi.org/10.1007/s00603-011-0166-1
Yilmaz NG (2013) The influence of testing procedures on uniaxial compressive strength prediction of carbonate rocks from Equotip hardness tester (EHT) and proposal of a new testing methodology: Hybrid dynamic hardness (HDH). Rock Mech Rock Eng 46:95–106. https://doi.org/10.1007/s00603-012-0261-y
Zhang H, Sun Q, Liu L, Ge Z (2020) Changes glossiness, electrical properties and hardness of red sandstone after thermal treatment. J Appl Geophys 175:104005. https://doi.org/10.1016/j.jappgeo.2020.104005
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The authors would like to appreciate the Azmouneh Foulad Consulting Engineering Company for their kind support in performing some of the laboratory tests.
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Ghorbani, S., Hoseinie, S.H., Ghasemi, E. et al. A new rock hardness classification system based on portable dynamic testing. Bull Eng Geol Environ 81, 179 (2022). https://doi.org/10.1007/s10064-022-02690-3
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DOI: https://doi.org/10.1007/s10064-022-02690-3