ELAICH - Educational Linkage Approach in Cultural Heritage. For more information and presentations, please visit: http://elaich.technion.ac.il/ Reverse engineering for compatible and performing restoration materials – case studies

1. Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou - NTUA – National Technical University of Athens The Conservation Process Module 4 Teaching Material Topic 4 . 8 Reverse engineering for compatible and performing restoration materials – case studies Advanced Topic Educational Toolkit

2. Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – National Technical University of Athens Copyright ©ELAICH Beneficiaries 2009-2012 This material is an integral part of the “ELAICH – educational toolkit” and developed as part of the project ELAICH – Educational Linkage Approach in Cultural Heritage within the framework of EuroMed Cultural Heritage 4 Programme under grant agreement ENPI 150583. All rights reserved to the ELAICH Beneficiaries. This material, in its entirety only, may be used in "fair use" only as part of the ELAICH – educational toolkit for the educational purposes by non-profit educational establishments or in self-education, by any means at all times and on any downloads, copies and or, adaptations, clearly indicating “©ELAICH Beneficiaries 2009-2011” and making reference to these terms. Use of the material amounting to a distortion or mutilation of the material or is otherwise prejudicial to the honor or reputation of ELAICH Beneficiaries 2009-2011 is forbidden. Use of parts of the material is strictly forbidden. No part of this material may be: (1) used other than intended (2) copied, reproduced or distributed in any physical or electronic form (3) reproduced in any publication of any kind (4) used as part of any other teaching material in any framework; unless prior written permission of the ELAICH Beneficiaries has been obtained. Disclaimer This document has been produced with the financial assistance of the European Union. The contents of this document are the sole responsibility of the ELAICH Consortium and can under no circumstances be regarded as reflecting the position of the European Union.

3. Abstract Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – National Technical University of Athens The current presentation examines the implementation of the reverse engineering methodology for the production of compatible restoration mortars simulating the original ones, and at the same time providing earthquake protection to the monuments.

4. Content Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – National Technical University of Athens Table of contents of this presentation Reverse Engineering Methodology Step 1: Characterization of historic mortars Step 2: Selection of raw materials Step 3: Preparation of mortars Step 4: Assessment of Mortars During their Setting and Hardening Period Step 5: Optimization – Standardization Step 6: Pilot application of restoration mortars

6. Educational Linkage Approach In Cultural Heritage 4.8.1 . Reverse engineering methodology A NESSESARY & APPROPRIATE METHODOLOGY FOR THE PRODUCTION OF COMPATIBLE RESTORATION MORTARS BASED ON CRITERIA THAT ORIGINATE FROM EXPERIENCE WITH HISTORIC MORTARS: Acropolis of Athens REVERSE ENGINEERING Simulation of the properties of historic mortars Improved properties of the compatible mortars Reproducibility and control of the production technology Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

7. Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials Acropolis of Athens Prof. A. Cakmak (PU), Prof. A. Moropoulou (NTUA) At the Dome of Haghia Sofia, Istanbul 1995

8. Educational Linkage Approach In Cultural Heritage Step 1. Characterization of historic mortars Mechanical tests (compressive / flexural strength)_____________mechanical properties Mercury intrusion porosimetry_______________________microstructural characteristics Water capillary rise tests_________________% absorbed water, capillary rise coefficient Optical / fibre optics / electron microscopy____microstructural characteristics and texture Thermal analyses_____________________________________phases and composition X-Ray Diffraction analysis_______________________________________crystal phases Other Non Destructive Techniques (DIP, IR Thermography, Ultrasonics, colorimetry, etc.) Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

9. Educational Linkage Approach In Cultural Heritage Step 1. Characterization of historic mortars Correlation between the tensile strength and the CO2 / structurally bound water ratio CO2 / structurally bound water vs. CO2 (%) Classification of the historic mortars with thermal analysis and mechanical tests Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

10. Educational Linkage Approach In Cultural Heritage Step 1. Characterization of historic mortars Assessment of the Microstructural Characteristics of Historic Mortars – Acceptable Limits for Restoration Mortars Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

11. Educational Linkage Approach In Cultural Heritage Step 1. Characterization of historic mortars Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials Optical Microscopy Ceramic – Matrix interface (reaction) Thermal Analysis DTA/DTG Characteristic Thermal Analysis result of Haghia Sophia historic mortar

12. Educational Linkage Approach In Cultural Heritage 2.4.2. Selection of building materials Prof. Antonia Moropoulou – Topic 2: Knowing the built heritage Step 1. Characterization of historic mortars Acropolis of Athens The penetration of lime into the ceramic and the consequent reaction transforms the microstructure of the ceramic by shifting the pore radii to smaller ranges, and augmenting the apparent density. The transformation of the pore size distribution matches with the hydraulic character of the mortar matrix, imparting to the mortar high physico-chemical resistance to polluted and marine atmosphere, as well as high strength. The development of an amorphous hydraulic calcium alumino-silicate gel between the crystalline phases of calcite and the dispersed ceramic fragments, evidenced by TEM, allows efficient energy absorption during earthquakes towards a higher level of crystallinity avoiding failure. Transmission Electron Microscope microphotographs of the crushed brick inclusions in the mortar matrix. The amorphous formations of the hydraulic C-H-S phases are visible (magn. x 22000 left, x 42000 right).

13. Educational Linkage Approach In Cultural Heritage Step 2. Selection of Raw Materials BINDERS Lime Putty Ca(OH)2 ~83%, CaCO3 ~15%, free water content ~58% , bulk density ~0,82 g/cm3 Raw material: Quicklime. This is added to water and a chemical reaction occurs which is termed as slaking. The resulting mixture is sieved and left to mature for at least 3 months. During this time the liquid slaked lime thickens to the consistency of toothpaste and is pure white in color Natural Hydraulic Lime (NHL) Raw material: limestone containing clay or other silica impurities. The limestone is burnt (~900oC) and then slaked (conversion of CaO to Ca(OH)2 without hydration of hydraulic phases), but a harder set is obtained because calcium silicates and aluminates form in the presence of water as well as calcium carbonate from carbonation. It can set under water hence the term hydraulic. NHL is graded by strength into three types 2, 3.5 and 5. These are termed, feebly hydraulic, moderately hydraulic and eminently hydraulic The selection criteria of the raw materials are based on studies of historic mortars and extensive lab experience Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

14. Educational Linkage Approach In Cultural Heritage Step 2. Selection of Raw Materials AGGREGATES Sand Washed yellow-colored river-sand of silicate nature Limestone sand can be used due to compatibility with the binder phase Grain size distribution according to application No impurities such as salts, clay-earths etc. Crushed Brick Grain size distribution 1-6mm, total porosity ~30%, bulk density: 1.89 g/cm3 Raw material of the crushed bricks should contain small quantities of CaCO3 ADDITIVES Earth of Milos – Natural Pozzolanic Additive High content of amorphous glassy phases, total silica 65% % finer than 64μm: 88, percentage active silicon >20% Brick Powder – Artificial Pozzolana Total silica 58%, % finer than 64μm: 94 percentage active silicon >20% Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

15. Educational Linkage Approach In Cultural Heritage Step 2. Selection of Compositions Lime Mortars Lime putty with sand, sand-brick, fine sand Binder / aggregate ratio 1:2 – 1:2.5 Hydraulic Mortars Hydraulic lime with sand, sand-brick, fine sand Binder / aggregate ratio 1:3 Mortars with Pozzolanic Additives Lime putty / ceramic powder (2:1) with sand, sand-brick Binder / aggregate ratio 1:2.5 Lime putty / Earth of Milos (2:1) with sand, sand-brick Binder / aggregate ratio 1:2.5 Comparison Mortars with Lime – Cement Lime putty / cement (1:4 to 1:1) with sand, sand-brick Cement to sand ratio 1:3 Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

16. Educational Linkage Approach In Cultural Heritage Step 3. Preparation of Mortars Mixing procedure: Mix the binder along with the pozzolanic additive using the appropriate content of water (as determined by the flow table test) Add gradually the premixed aggregate materials Technical Characteristics of the fresh mortars: Air content Bulk density Retained water Consistence – flow table test Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

17. Educational Linkage Approach In Cultural Heritage Step 4. Assessment of Mortars During their Setting and Hardening Period Differential Thermal Analysis – Thermogravimetry Carbonation / development of hydraulic phases Microstructural Investigation with Mercury Intrusion Porosimetry Assessment of the compatibility of historic mortars Mechanical Properties Response to the structural - static specifications Characterization Methods Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

18. Educational Linkage Approach In Cultural Heritage Step 4. Assessment of Mortars During their Setting and Hardening Period Hydraulic lime mortars Chemically bound water after only 15 days of hardening. High mechanical strength. High hydraulicity Typical Lime Mortars Lowest carbonation rate (it continues even after 9 months). Rate increases after 3 months. Mechanical strength is developed in relation with the carbonation rate Pozzolanic Mortars (ceramic powder, earth of Milos) Average values of carbonation rates. Significant amount of chemically bound water. The ceramic powder and the earth of Milos help the development of hydraulic phases improving the mechanical strength After 9 months Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

19. Educational Linkage Approach In Cultural Heritage Step 4. Assessment of Mortars During their Setting and Hardening Period Cement - lime mortars Low percentage cement mortars have a behavior similar to lime mortars. A separation of phases between cement and lime is observed, thus the binder material lucks cohesion High percentage cement mortars have high mechanical strengths but their microstructure is incompatible After 9 months Cement in any percentage is incompatible in restoration mortars for historic masonries Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

20. Educational Linkage Approach In Cultural Heritage 2.4.2. Selection of building materials Prof. Antonia Moropoulou – Topic 2: Knowing the built heritage Step 4. Assessment of Mortars During their Setting and Hardening Period COMPARATIVE DIAGRAMM OF PORE DISTRIBUTION CEMENT MORTAR – LIME MORTAR AND HYDRAULIC LIME MORTAR

21. Educational Linkage Approach In Cultural Heritage 2.4.2. Selection of building materials Prof. Antonia Moropoulou – Topic 2: Knowing the built heritage Step 1-5: Conclusions The systems with lime and hydraulic mortars present compatibility with the reference stone during evaporation, while the system with cement mortar present incompatible behavior and different levels of humidity concentration during evaporation (monitoring with infra red thermography) STONE – LIME MORTAR – STONE SYSTEM STONE – CEMENT MORTAR – STONE SYSTEM STONE – HYDRAULIC MORTAR – STONE SYSTEM

24. Educational Linkage Approach In Cultural Heritage Step 5: Optimization - Standardization Optimization of the Binder / Additives / Aggregates Ratio Increase the binder phase by 5-10% Improvement of the mechanical properties and the microstructure Binder / additives = 1:1 Enhancement of the hydraulic character of the mortar Optimization of the Production Technology Saturation of the crushed brick Avoid problems with mortar setting Improved mixing procedure Mix the binder with the additives and all the necessary water and slowly add the aggregates Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

26. Educational Linkage Approach In Cultural Heritage Step 1-5: Conclusions Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials FINITE ELEMENT ANALYSIS MODEL FOR THE EVALUATION OF THE EARTHQUAKE RESPONSE OF THE MONUMENT WITH THE PROPOSED RESTORATION MORTARS (Bogazici University, Prof. Mustafa Erdik)

27. Educational Linkage Approach In Cultural Heritage Step 6: Pilot Application of Restoration Mortars Characterization of Historic Mortars Design of Compatible Restoration Mortars Optimization & Standardization Pilot Application of Restoration Mortars Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

28. Educational Linkage Approach In Cultural Heritage Pilot Application of Restoration Mortars The structural system of the Church is characterized by a masonry with joints of large thickness (almost 1,5 times the thickness of the brick) and strong crushed brick mortars Historic Masonry in Hagia Sophia, Istanbul Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

29. Educational Linkage Approach In Cultural Heritage Pilot Application of Restoration Mortars Low dynamic modulus of elasticity and relatively high flexural strength In this way, the materials contributed to the earthquake resistance of the monument Characteristics of the historic mortars used in Hagia Sophia Hydraulic nature of the binder A mixture of coarse ceramic fragments (<15mm) and sand was used as aggregates These mortars may be considered as early examples of reinforced concrete Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials Material E d (MPa) F f (MPa) Mortar 0.66 0.7-1.2 Brick-mortar 1.83 - Brick 3.1 -

30. Educational Linkage Approach In Cultural Heritage Pilot Application of Restoration Mortars Site of Pilot Application of Restoration Mortars Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials

31. Educational Linkage Approach In Cultural Heritage 2.4.2. Selection of building materials Prof. Antonia Moropoulou – Topic 2: Knowing the built heritage Pilot Application of Restoration Mortars Pilot application of repair mortars on a specific masonry of Haghia Sophia for monitoring reasons (October 2000) NTUA in situ campaign The masonry where the pilot application of repair mortars was made The masonry after the pilot application of repair mortars Specific mortar syntheses following the above NTUA proposals were adjusted to the restoration works by the Istanbul Technical University and were applied under the supervision of the Directorate of Haghia Sophia that is responsible for the earthquake protection works. These mortars proved efficiency during the earthquake of August 1999.

32. Educational Linkage Approach In Cultural Heritage Prof. Antonia Moropoulou – Topic 4.8 : Reverse engineering for compatible and performing restoration materials Applied Restoration Mortars Mortar with Lime Putty & Brick Powder as a pozzolanic additive and aggregate mixture of Sand and Crushed Brick (LPPBSCB) Mortar with natural Hydraulic Lime & Brick Powder as a pozzolanic additive and aggregate mixture of Sand and Crushed Brick (HLPBSCB) Mortar with Lime Putty & earth of Milos as a pozzolanic additive and aggregate mixture of Sand and Crushed Brick (LPMCSCB)

33. Educational Linkage Approach In Cultural Heritage REFERENCES Prof. Antonia Moropoulou – Topic 2.7.2: Earthquake resistant mortars

34. Educational Linkage Approach In Cultural Heritage Cakmak, A.S., Moropoulou, A., Mullen, C.L., “Interdisciplinary Study of Dynamic Behaviour and Earthquake Response of Hagia Sophia”, J. Soil dynamics and earthquake engineering, 14, No 9 (1995) pp. 125-133. Moropoulou, A., Bakolas, A., Bisbikou, K., &quot;Thermal analysis as a method of characterizing ancient ceramic technologies”, Thermochimica Acta, 2570 (1995) pp. 743-753. Moropoulou, A., Bakolas, A., Bisbikou, K., “Characterization of ancient, byzantine and later historic mortars by thermal analysis and X-ray diffraction techniques”, Thermochimica Acta, 269/270 (1995) pp. 779-795. Moropoulou, A., Cakmak, A.S., Bakolas, A., Labropoulos, K., Bisbikou, K., “Properties and Technology of the crushed brick mortars of Hagia Sophia”, Soil Dynamics and Earthquake Engineering VII, ed. A.S. Cakmak and C.A. Brebbia, Computational Mechanics Publications, Southampton Boston (1995) pp. 651-661. Moropoulou, A., Cakmak, A., Biscontin, G., “Crushed brick / lime mortars of Justinian’s Hagia Sophia”, Materials Issues in Art and Archaeology V, Vol. 462, ed. P.B. Vandiver, J.R. Druzik, J.F. Merkel, J. Stewart, Publ. Materials Research Society, Pittsburgh (1997) pp. 307-316. Cakmak, A.S., Erdik, M., Moropoulou A., “A joint program for the protection of the Justinian Hagia Sophia”, in Proc. 4th International Symposium on the Conservation of Monuments in the Mediterranean Basin, ed. A. Moropoulou, F. Zezza, E. Kollias & I. Papachristodoulou, Publ. Technical Chamber of Greece, Rhodes, Vol. 4 (1997) pp. 153-171. Bakolas, A., Biscontin, G., Moropoulou, A., Zendri, E., “Characterization of structural byzantine mortars by thermogravimetric analysis”, Thermochimica Acta, 321 (1998) pp. 151-160. Moropoulou, A., Cakmak, A.S., Biscontin, G., “Criteria and methodology to evaluate the Hagia Sophia crushed brick / lime mortars”, PACT, J. European Study Group on Physical, Chemical, Biological and Mathematical Techniques Applied to Archaeology, 55 (1998) pp. 39-54. Cakmak, A.S., Moropoulou, A., Erdik, M., “Dynamic behaviour and earthquake response of Hagia Sophia”, PACT, J. European Study Group on Physical, Chemical, Biological and Mathematical Techniques Applied to Archaeology, 56 (1998) pp.31-47. Moropoulou, A., Bakolas, A., Moundoulas, P., Cakmak A.S., “Compatible restoration mortars, preparation and evaluation for Hagia Sophia earthquake protection”, PACT, J. European Study Group on Physical, Chemical, Biological and Mathematical Techniques Applied to Archaeology, 56 (1998) pp. 79-118. Prof. Antonia Moropoulou – Topic 2.7.2: Earthquake resistant mortars