._F ‘A, 4.• 4,‘ - seIc A- • • CULTURAL PROPERTY 116 CAR OM IY TIERNATIOIVAL CENTRE FOR rlit STUDY OFT -IC PRESERVATION .AND TM4 nreorroinn,oru OF .. CIENTPL INITIIFINATIONAL O.IITLIO•• POUR L CONSERVATION ETLARUSTAURATION DRS Riff CULTUREL• V yr I `4, "••••••••••••••••••....... • 1 • • ARAAA.R. - 41/.. vro • 4 '71:11r7 e Mortars, Cemeilts and Grouts used in the Conservation of Historic Buildings . - • Mortiers, cjniegts et coulis utilises du:10a conservation des batiments historiques Symposium 3- 6.11.1981 Rome • • • • • • .....•••••1•-••••••• •tr - • I • .••••• • • ihem,:s • t • • • 4"' • 1 .s.muhor •04.0...40•411.-•• -•••• -.ORR ••••••••• •.••••••••• •'• 1"."114"4" • • • • A BIBLIOTHEQUE 5 7() o AEJVHEIn xt?ç """"•.. ICCROM Mortars, Cements and Grouts used in the Conservation of Historic Buildings Mortiers, ciments et coulis utilisés dans la conservation des bâtiments historiques Symposium 3- 6.11.1981 Rome Rome 1982 CONTENTS INTRODUCTION p. 1 Section 1 Mortars for renderings, repointing and masonry repairs. Mortiers pour enduits, rejointement et reparation des maconneries. V. FURLAN Experiences pratiques avec des crepis A base de chaux. 9 I. HOLMSTROM Mortars, cements and grouts for conservation and repair. Some urgent needs of research p. 19 L. B. SICKELS Organics vs. synthetics : their use as additives in mortars. p. 2 5 S. PETERSON Lime water consolidation. p. 53 S. PERONI and others Lime-based mortars for the repair of ancient masonry and possible substitutes. p. 63 S. Z. LEWIN X-ray diffraction and scanning electron micro- scope analysis of conventional mortars. p. 101 III P. BALDI - M. CORDARO - L. MORA - P. MORA Architecture - couleur p. 133 T. PERANDER Mortar - study in Finland. Maintenance of historic buildings. p. 141 Section 2 Grouts and injections in ancient masonry. Coulis et injections dans les maçonneries anciennes. R. SENGUPTA Grouting for strengthening the Qutb Minar, Delhi p. 147 A. BOUINEAU, J. ROCARD Reinforcement des maçonneries pour injections de coulis dans la region nord-est de la France. p. 165 D. FERRAGNI - J. MALLIET et autres Essais de laboratoire sur des coulis à base de ciment. p. 185 Section 3 : Portland cement and special cements ; their use in conservation. Ciment Portland et ciments spéciaux ; leur utilisation dans la conservation. A. E. CHAROLA Study of hydrated cement pastes of aged concretes from Acropolis monuments. p. 207 IV F. MASSAZZA, M. PEZZUOLI Some teachings of a Roman concrete p. 219 Section 4 Use of synthetic resins in mortars and grouts. Utilisation des r4sines synthetiques dans les mortiers et les coulis. P. BALDI Tharros (Oristano, Sardinia) : Preservation of the Punic ditch. Methodological considerations. p. 249 M. LOLLI GHETTI Tharros (Oristano, Sardinia) : Conservation of the Punic ditch : Diversification of technologies. p. 255 M. BELLINI Tharros (Oristano, Sardinia) : Conservation of the Punic ditch. The operational technique. p. 267 G. RUGGIERI L'obelisque de place S. Giovanni in Laterano Rome. p. 273 Section 5 : Study and analysis of ancient mortars and renderings. Etude et analyse des mortiers et enduits anciens. M. DU PAS L'analyse des mortiers et enduits des peintures murales et des bdtiments anciens. p. 281 V J. MOORE, J. STEWART Chemical techniques of historic mortars analysis. p. 297 H. JEDRZEJEWSKA Ancient mortars as criterion in analysis of old architecture. p. 311 M. FRIZOT L'analyse des mortiers antiques ; problemes et resultats. p. 331 R. MALINOWSKI Ancient mortars and concretes; durability aspects. p. 341 C. MEUCCI, P. ROSSI DORIA Analyse et caracterisation de quelque type d'ancient mortiers orientals. p. 351 G. BISCONTIN, M. PIANA, G. RIVA Research on limes and intonacoes of the historical Venetian architecture. p. 359 L. MORA Les materiaux des enduits traditionnels. p. 375 E. ARMANI, M. PIANA Research on the plaster of Venetian Historic Buildings. p. 385 Conclusions and Recommendations p. 403 Conclusions et Recommandations VI INTRODUCTION The problem of the use (and abuse) of mortars in historic buildings must be considered a prominent one, if one thinks of the vital role that mortar properties play in the funcioning of a structure and its outer skin. Yet this domain has received, up to the present moment, far less attention than that of the conservation of stone, a material which is comparatively less important from a quantitative point of view but is more in the public eye beca.use ma.ny important works of art or famous structures are carved in stone. This lack of attention leads to a series of unfortunate consequ- ences such as those given below : a, mortars and renderings are an important source of histor- ical information, which is insufficiently exploited ; their study is neglected, and original materials are often destroyed without preservation of samples and proper documentation ; b. injection of grouts is used to stabilize old masonry without any theoretical consideration of requirements for the material to be injected and of the future behaviour of the grouted structures under environmental stresses ; c. mortars of insufficient porosity and excessive strength, which form dangerous by-products in their setting reactions. are frequently used in contact with old masonry and even near import- ant works of art (mural paintings, stuccoes or bas-reliefs). This list is by no means exhaustive; undoubtedly other lament- able effects of the neglect of mortar studies can be easily added. With such considerations in mind, ICCROM decided to devote its 1981 annual technical symposium to mortars and grouts in old buildings, including both the study of old materials and the use of new ones. 1 A survey of the available technical literature allowed us to draft a list of persons active in the field, who could make an interesting contribution to the symposium. We are quite conscious, however, that some relevant research programmes and interested specialists may have never been aware of the meeting, as it was publicized only in journals and newsletters devoted to conservation, and our initial list of invited experts was obviously incomplete. Notwithstanding such limitations, we were fortunate enough to bring together about seventy professionals who attended three days (3, 4 and 5 November, 1981) of meetings devoted to the presentation and discussion of 26 papers. ICCROM also presented two symposium papers produced in its research programmes. The studies were carried out by former course participants under the supervision of ICCROM technical staff and with the cooperation of scientific laboratories in Rome. It is a tradition of ICCROM technical symposia that an attempt is made to give some propulsion to further activities in the domain under consideration. To that purpose, one half of the last day was devoted to the informal meetings of two working groups : one on the study of ancient mortars, the other on the use of mortars and grouts in conservation. The two groups prepared recommendations which indicate the domain and objectives of possible future research projects consid- ered of importance for the study and the conservation of ancient buildings. These recommendations were approved in a short final session of the symposium and are included (in both French and English) at the end of this volume. On 6 November 1981 the symposium was closed by an excursion to Tuscania, about 60 miles north of Rome, which allowed the participants to review the use and abuse of mortars in the conserv- ation of an earthquake-stricken medieval town, In the publication of this volume, priority was given to speed and timeliness and, therefore, to simplicity. Papers were reprod- uced as presented by the authors, with little or no editing. 2 Authors are responsible for the choice and the presentation of the facts contained in their signed articles and for the opinions expressed therein, which are not necessarily those of ICCROM. Discussions could not be included, but an echo of them is reflected in the recommendations drafted by the working groups at the end of the meeting. We hope that the publication of the symposium proceedings will help further expansion of mortar studies, particularly along the lines which now appear of prominent historical and technolog- ical interest, in particular : 1. history of the technology of ancient mortars, based on large numbers of accurate, standardized analyses ; 2, development of a system of standard tests, and specific- ations explicitly meant for conservation mortars ; 3, study of new compositions of mortars designed to fulfil specific conservation needs. 3 INTRODUCTION Le problème de l'utilisation (et de l'abus) du mortier dans les monuments historiques doit être considéré comme majeur si l'on pense au rôle essentiel joué par le mortier dans le fonctionnement de la structure et sa couche extérieure. Ce domaine a pourtant reçu moins d'attention que celui de la conservation de la pierre, un matériau comparativement moins important mais davantage en vue, beaucoup d'oeuvres d'art ou de sculptures célèbres étant taillées dans la pierre. Ce manque d'attention a amené toute une série de conséquences indésirables telles que celles indiquées ci-dessous : a, les mortiers et les enduits sont une source importante d'infor- mations historiques, non suffisamment exploitée. Leur étude est négligée et des matériaux originaux sont souvent détruits sans qu'on ait effectué des prélèvement d'échantillons et sans documentation adéquate. b. l'injection des liants est utilisée pour stabiliser des maçon- neries anciennes sans aucune considération théorique des qualités requises pour l'injection et du comportement ultérieur des structures ainsi injectées sous les pressions de l'environnement. c. des mortiers d'une porosité insuffisante et d'une résistance trop grande ou qui réagissent par la formation de résidus dangereux au cours de leur phase de prise, sont souvent mis en contact avec des maçonneries anciennes ou même utilisés à proximité d'oeuvres d'art de grande valeur (peintures murales, stucs, bas-reliefs). Cette liste est incomplète : on pourrait facilement trouver d'autres exemples de ces conséquences désastreuses dues au manque d'étude sur les mortiers.