Porphyritic coarse-grained GRANITE (ID: 007) GEOLOGICAL CLASSIFICATION (Genetic classification) Introductory Granite is a phaneritic texture, light-coloured igneous rock composed mainly of feldspars definition (visu) and quartz with minor amounts of mica and amphibole minerals. Petrologist's Granite is a plutonic rock in which quartz makes up between 10 and 50 percent of the definition felsic components and alkali feldspar accounts for 65 to 90 percent of the total feldspar content. Commercial In the commercial stone industry, a “granite” is a rock with visible grains that is harder definition (if any) than a marble. Under this definition gabbro, basalt, pegmatite, schist, gneiss, syenite, monzonite, anorthosite, grannodiorite, diabase, diorite and many other rocks will be called “granite”. GEOMECHANICAL CLASSIFICATION (Behavioural classification, Goodman, 1989) I. Crystalline texture D. Randomly oriented and distributed silicates minerals of uniform grain size. DESCRIPTION OF LOCAL SAMPLE Geological Guimarães granite. The region of “Penha” (Guimarães, Portugal) is of granitic nature. description of local The Granite being predominant. This sample is a porphyritic coarse-grained biotite sample granite (monzogranite), with potassium feldspar megacrystals. Their colour is light yellow-brown due to alteration of mafic minerals (Pinto et al., 2010). It can be note that rocks with greater than 90% felsic minerals can also be called leucocratic, meaning 'light-coloured Other information The sample outcropping at Hercynian syn-tectonic granitic plutons associated to the about the outcrop Vigo-Régua shear zone and their age is about 300 Ma. (Dias et al. 1998, Simoes, 2000) Weathering grade of II sampling outcrop (ISRM, 1981) Location 41° 26' 0.70" N, 8° 16' 10.03" W ENGINEERING CLASSIFICATION OF INTACT ROCKS (General classification) ISRM classification R0 R1 R2 R3 R4 R5 R6 by strength. USC Extremely Very Weak Medium Strong Very Extremely (MPa) (ISRM, 1981) weak weak (5-25) strong (50-100) strong strong (0.25-1) (1-5) (25-50) (100- (>250) 250) Deere and Miller classification by strength and deformation properties (Deere and Miller, 1966)

Mechanical General values Particular (local) properties values (if any) (unaltered) Young’s Modulus (E) (GPa) 6.41–52.7 (AASHTO, 2002) Poisson’s coefficient (ν) 0.09–0.39 (AASHTO, 2002) Uniaxial compression strength (MPa) 14–338 (AASHTO, 2002) P wave velocity 5500–6000 (Fourmaintraux, 1976) mi (Hoek and Brown criterion, 1980) 20±5 (Hoek, 2006) Basic friction angle (Φb) 31–35 (Barton and Chaubey, 1977) Physical properties Dry unit weight (kN/m3) 26 (Goodman, 1989) (unaltered) Porosity 0–1 (Goodman, 1989) Engineering uses and Support plane foundation, building material, concrete aggregate, ballast, rip-rap, ashlar, others masonry, slabs, paving, tile floors, decorative features, monuments, etc. References: • Barton N, Choubey V (1977) The shear strength of rock joints in theory and practice. Rock Mech Rock Eng 10:1–54 . doi: 10.1007/BF01261801 • Fourmaintraux, D., 1976. Characterization of rocks; laboratory tests, ChapterIV in La Mécanique des roches appliquée aux ouvrages du génie civil by Marc panet et al. École Nationale des Pnts et Chausées, Paris • Goodman, R.E., 1989. Introduction to Rock Mechanics, 2nd edition. John Wiley and Sons. New York • Hoek E, Brown ET (1997) Practical estimates of rock mass strength. Int J Rock Mech Min Sci. doi: 10.1016/S1365-1609(97)80069-X • Hoek, 2006. Practical rock engineering. Available in https://www.rocscience.com/learning/hoeks-corner • ISRM (1981) Rock characterization. In: Brown ET (ed) Testing and monitoring— ISRM suggested methods. Pergamon press, Oxford, p 211 • Krsmanovic D (1967) Initial and residual shear strength of hard rocks. Géotechnique 17:145–160 . doi: https://doi.org/10.1680/geot.1967.17.2.145 • Transportation Officials. (2002). Standard specifications for highway bridges. AASHTO.

Last modified: 13 February 2019