1. Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou - NTUA – National Technical University of Athens Educational Toolkit The Conservation Process Module 4 Teaching Material Topic 4.74.74.74.7 Criteria & Methodology for Consolidation Pilot applications & case studies Advanced Topic

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3. Abstract Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – National Technical University of Athens This presentation introduces the theme of consolidation, one of the major types of conservation interventions applied on the built heritage. The definition of consolidation and the aim of its application are explained. Selection criteria and the basic types of consolidation materials are also pointed out. Moreover, the advantages of advanced particle modified consolidants are presented, along with the assessment methodology of consolidation materials. For the better understanding of the theoretical background of consolidation, the case study of Medieval City of Rhodes is presented. Examples of pilot application of consolidation materials are displayed, whereas representative results of analytical and NDT techniques applied on site for the assessment of consolidants are demonstrated.

4. Content Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – National Technical University of Athens Table of contents of this presentation 4.7.1 Consolidation definition and aim of its application 4.7.2 How do we select consolidants- criteria 4.7.3 Basic types of consolidants 4.7.4 Advantages of advanced particle modified consolidants 4.7.5 Assessment methodology of consolidation materials 4.7.6 Examples of pilot consolidation interventions application – the case study of Medieval City of Rhodes 4.7.7 Assessment of pilot consolidation interventions – presentation of representative results 4.7.8 Assessment conclusions

5. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Consolidation Interventions are applied for the rehabilitation of the decayed stone cohesion. What is the aim of the application of consolidation materials and interventions?  Modification of micro structural characteristics of the stone, leading to lessening of stone susceptibility to salt decay  Prevention of decay due to grains de-cohesion  Amelioration of mechanical characteristics of the stone Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

6. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Which are the criteria used for the selection of consolidation materials and interventions?  Increase of strength and durability of the materials for their whole lifetime  Satisfactory penetration depth  Change of the porosity distribution so that: - Decrease the susceptibility to decay and salt crystallization - Ensure the compatibility with isotropic transfer of water/vapor in the masonry  Physicochemical and mechanical compatibility between the healthy and the consolidated stone (lack of byproducts, soluble salts, comparable thermal expansion coefficient and water vapor permeability, etc.)  Avoid changing the color of the surface  Increased lifetime Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

7. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Which are the types of the consolidation materials? Inorganic Materials  Chemical relevance with lithotype  Production of shallow, hard crusts  Production of by-products Organic Materials  Improvement of mechanical properties  Production of glossy crusts  Degradation by oxygen and UV radiation Alkoxysilanes  Ability of deep penetration to siliceous sandstones  Polymerization may occur after penetration, and then form products similar to the siliceous sandstone binder Advanced Particle Modified Consolidants  To solve the problem of visco-elastic behavior of the consolidant Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

8. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Silica Colloid Polymer Composite Silicate matrix (e.g. TEOS, Conservare OH-100) Colloid particles (silica, titania, or various pigments (oxides of iron, chrome, and cobalt). The powders can be stabilized against aggregation by coating them with nanometric silica particles, so that they form low-viscosity suspensions that readily penetrate stone. Advantages  The presence of the particles reduces the shrinkage during drying, yielding nearly zero shrinkage for particle loadings above 20 vol%. This means that the gels do not crack during drying and rewetting cycles, so their effectiveness as a binder is retained.  By using a mixture of oxide particles, it is possible in principle to match a range of properties, such as color and CTE.  The permeability of the consolidant is dependent on the size of the particulate inclusions, so it can also be independently controlled.  Advanced Particle Modified Consolidants are used to solve the problem of viscoelastic behavior of the consolidant Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

9. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Advanced Particle Modified Consolidants PMC in Ohio sandstone. Small spheroidal particles are titania pigment. Dynamic elastic modulus of Ohio Masillian sandstone before and after consolidation with PMC (●, ◦) and Conservare OH-100 ( , Δ) Aggelakopoulou E., Charles P., Acerra M.E., Garcia A.I., Flatt R.J. and Scherer G.W. “Rheology Optimization of Particle Modified Consolidants” in Materials Issues in Art & Archaeology VI, MRS Symposium Proc. Vol. 712, eds. P.B. Vandiver, M. Goodway, and J.L. Mass (Materials Res. Soc., Warrendale, PA, 2002) pp.15-20 Escalant M.R., Flatt R., Scherer G.W., Tsiourva D., Moropoulou A. “Particle-modified Consolidants”, in Protection and Conservation of the Cultural Heritage of the Mediterranean Cities, eds. E. Galán and F. Zezza (Balkema, Lisse, The Netherlands, 2002) pp. 425-429 Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

10. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Which is the methodology followed for the assessment of the applied consolidation materials and interventions? PropertyMeasurementTechnique Physicochemical compatibility Assessment of permeability and water- absorption In situ: IR Thermography Lab: Water sorption measurements Cohesion enhancementAssessment of consolidation penetration depth In situ: Utrasonics Lab: Mechanical strength tests Whether the modification of the microstructural characteristics increases the durability (physicochemical strength) against environmental loads Assessment of microstructure and decay rate In situ: Fibre Optics Microscopy Lab: Microstructural measurements and accelerated ageing tests Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

11. Educational Linkage Approach In Cultural Heritage Acropolis of Athens  Selection of the most appropriate consolidation materials and techniques, based on laboratory measurements.  Selection of locations for pilot application of consolidation in situ and performance of evaluation techniques in lab and in situ. Pilot application of Consolidation Interventions in the Medieval City of Rhodes Consolidants used RP: Ethyl silicate EU: Acryl-siliconic resin in organic solvent PH: Ethyl silicate 20% in alcohol solution PL: Aqueous colloidal dispersion of extremely small silica particles (12 nm), with consequently large specific surface area Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

12. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Building material: Fossiliferous calcareous highly porous stone, where microcrystalline calcitic binder is embedded by calcareous aggregates Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

13. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Application Sites Immediately after the application of consolidation 3 months after the application of consolidation Entrance of the Moat Masonry constructed of smaller and equally sized blocks of concrete and less deteriorated stone. The humidity level of the stone was lower than in St Paul’s Gate. Moropoulou, Tsiourva, Theoulakis, Koui et. al, 2000 Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

14. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Immediately after the application of consolidation 3 months after the application of consolidation St Catherine ’ s Hospice The application was performed on internal wall surfaces, recently restored by freshly quarried stones, yet presenting recession of the surface and material loss. Application Sites Moropoulou, Tsiourva, Theoulakis, Koui et. al, 2000 Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

15. Educational Linkage Approach In Cultural Heritage Acropolis of Athens St Paul ’ s Gate In vicinity to the sea. The application surface is south oriented and the backside of the walls is continuously fed by salt solution due to the sea environment. Application Sites Immediately after the application of consolidation 3 months after the application of consolidation Moropoulou, Tsiourva, Theoulakis, Koui et. al, 2000 Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

16. Educational Linkage Approach In Cultural Heritage Acropolis of Athens 15 months after intervention St Paul ’ s Gate Medieval City of Rhodes Presence of humidity in a porous material causes IR emission variations Physicochemical Compatibility Moropoulou, Koui, Kourteli, Theoulakis, Avdelidis, 2001 Assessment of Pilot Consolidation Interventions Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

17. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Physicochemical Compatibility NC CSPH2 CSPL3 CSEU1 CSRP4 Good compatibility Not satisfactory compatibility Non consolidated Non Consolidated Stone Moropoulou, A., Bakolas, A., Moundoulas, P., Aggelakopoulou, E., Anagnostopoulou, S., 2001 EU PL PH RP Assessment of Pilot Consolidation Interventions Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

18. Educational Linkage Approach In Cultural Heritage Acropolis of Athens The use of resins in consolidation interventions results in: Problems with “breathing” of the masonry Salt crystallization behind the deposition layer that leads to material detachment Application of Incompatible Consolidants through Filmogenic Deposition Moropoulou, Tsiourva, Theoulakis, Koui 1998 Assessment of Pilot Consolidation Interventions Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

19. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Modification of Microstructure Non- treated Treatment with Ludox: SEM Treatment with Silbond: SEM Moropoulou, Tsiourva, Theoulakis, Koui et. al, 2000 Assessment of Pilot Consolidation Interventions Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

20. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Before consolidationAfter consolidation Evaluation of porous stone surface in the Medieval City of Rhodes with Fibre Optics Microscopy Moropoulou, Tsiourva, Theoulakis, Koui et. al, 2000 Modification of Microstructure Assessment of Pilot Consolidation Interventions Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

21. Educational Linkage Approach In Cultural Heritage Acropolis of Athens FTIR for non treated and treated porous stone samples – Medieval City of Rhodes Moropoulou, A., Tsiourva, Th., Biscontin, G., Bakolas, A., Michailidis, P., Zendri, E., 1997 Assessment of Pilot Consolidation Interventions Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

22. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Assessment of consolidant penetration depth in treated porous stone compared to non-treated porous stone using ultrasonics The application of consolidants enhances cohesion Moropoulou, Christaras, Tsiourva 1998 Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies

23. Educational Linkage Approach In Cultural Heritage Acropolis of Athens Conclusions  PL, PH, RP present similar performance according to the parameters examined.  EU declines considerably, according to observations obtained by FOM and IR thermographs.  A shifting of pore size distribution versus smaller pore radius, as well as percentage reduction of large pores, was observed for the treated stone samples. This fact can be attributed to the deposition mechanism of the consolidant on the pore wall surfaces (formation of films). Prof. Antonia Moropoulou - Topic 4.7: Criteria & Methodology for Consolidation - Pilot applications & case studies