Issue 50

A. Marinelli et alii, Frattura ed Integrità Strutturale, 50 (2019) 438-450; DOI: 10.3221/IGF-ESIS.50.37 449 For tests performed within the scope of this investigation, the variation of the strength and fracture energy with increasing specimen’s size appears to be monotonic, a behaviour that is commonly observed for concrete [24] but not necessarily for a selection of other natural building stones [18, 25-29]. Given the significant scattering of results for this kind of natural building stones and the scale limitations for this experimental study, definite conclusions for the size- and shape-effects cannot yet be drawn and further experimental evidence would be required. The above requirement is imperative in an effort to fully explore the behaviour laws covering transition from the scale of ‘materials’ to that of ‘structural members’ and choose accordingly specimens that are representative of the material’s behaviour and useful for design purposes. R EFERENCES [1] Australia ICOMOS (2013). The Burra Charter: The Australia ICOMOS Charter for Places of Cultural Significance. Available at: http://australia.icomos.org/wp-content/uploads/The-Burra-Charter-2013-Adopted-31.10.2013.pdf. [2] UNESCO World Heritage Committee (2017). The Operational Guidelines for the Implementation of the World Heritage Convention. Available at: http://whc.unesco.org/en/guidelines. [3] Historic Environment Scotland (2017). Advisory Standards of Conservation and Resilience for the Historic Building Environment in Scotland. Available at: https://www.historicenvironment.scot/archives-and-research/publications. [4] Fairhurst J., Gillanders R., McMillan A. (1999). Building Stones of Edinburgh, Edinburgh Geological Society (2nd Ed.). [5] Hyslop E., McMillan A., Maxwell I. (2006). Stone in Scotland, UNESCO Publishing. [6] Anderson, T.L. (1995). Fracture Mechanics: Fundamentals and Applications. Florida: CRC Press, Inc. [7] Kourkoulis, S.K., Exadaktylos, G.E., Vardoulakis I. (1999). U-notched Dionysos-Pentelicon marble in three point bending: The effect of nonlinearity, anisotropy and microstructure. Int. J. Fracture; 98(3-4), pp. 369-392. DOI: 10.1023/A:1018614023542. [8] Bažant, Z.P. and Yavari, A. (2005). Is the cause of size effect on structural strength fractal or energetic-statistical?. Eng Frac. Mech; 72, pp. 1-31. DOI: 10.1016/j.engfracmech.2004.03.004. [9] Ravaisson-Mollien, C. ed., (1883). Les Manuscripts de Léonard de Vinci, Transl. in French by Institut de France, 3. [10] Weston, T. ed., (1730) Galileo, Galilei: Discorsi e Dimostrazioni Matematiche intorno a due Nuove Scienze, Elsevirii, Leiden. English transl., pp.178-181. [11] Fisher R.A., Tippett L.H.C. (1928). Limiting forms of the frequency distribution of the largest and smallest member of a sample. Proc. Cambridge Philos. Soc. 24, pp. 180-190. DOI: 10.1017/S0305004100015681. [12] Weibull W. (1939). The phenomenon of rupture in solids. Proc. R. Swed. Inst. Engng Res. (Ing. Akad. Handl. Sweden) 153, pp. 1-55. [13] Walsh P.F. (1972). Fracture of plain concrete. Indian Concr. J. 46(11), pp. 469-70, 476. [14] Bažant, Z.P. (1984). Size effect in blunt fracture: concrete, rock, metal. J. Eng. Mech. 110, pp.518-535. DOI: 10.1061/(ASCE)0733-9399(1984)110:4(518). [15] Carpinteri A. (1994). Fractal nature of material microstructure and size effects on apparent mechanical properties. Mech Mater. 18. pp. 89-101. DOI: 10.1016/0167-6636(94)00008-5. [16] Carpinteri A., Chiaia A., Cornetti P. (2003). On the mechanics of quasi-brittle materials with a fractal microstructure. Eng. Frac. Mech. 70, pp. 2321-2349. DOI: 10.1016/50013-7944(02)00220-5. [17] Vayas I., Marinelli A., Kourkoulis S.K, Papanicolopulos S.A. (2009). Investigating the Fracture Behaviour of Dionysos Marble: an experimental study. In: Protection of Historical Buildings, II, Mazzolani F.M. (Ed.), A. Balkema Book, Boca Raton, pp. 1699-1704. [18] Kourkoulis S. K., Ganniari-Papageorgiou E. (2010). Experimental study of the size and shape effects of natural building stones. Construction and Building materials; 24(5), pp. 803-810. DOI: 10.1016/j.conbuildmat.2009.10.027. [19] Leary E. (1983). The Building Limestones of the British Isles, Building Research Establishment Report, Department of the Environment, UK. [20] RILEM Technical Committee 50-FMC (1985). Draft Recommendation: Determination of the Fracture Energy of Mortar and Concrete by means of Three-Point Bend Tests on Notched Beams, Materials and Structures 106, pp. 285-290. [21] Hillerborg A. (1983). Concrete Fracture energy tests performed by 9 laboratories according to a draft RILEM recom- mendation: Report to RILEM TC50-FMC (Report TVBM; Vol.3015). Division of Building materials, LTH, Lund University.