With the development of micro-LIBS imaging, the ever-increasing size of datasets (sometimes >1 million spectra) makes the processing of spectral data difficult and time consuming.

Lime mortar is a complex mixture resulting from hardening of lime, water, and aggregates. Lime mortar was used from the time of the Roman Empire until the Industrial Revolution. The recipes used differ according to the period, geographical area of preparation, craftsman, or function. This is why the study of archaeological mortars is of such great importance in building archaeology. In this study, we used laser-induced breakdown spectroscopy (LIBS) to characterize the elemental composition of three lime mortar samples with a µ-LIBS instrument, allowing elemental image compilation. These samples originate from three different geographical locations: Angers (France), Dardilly (France), and Pompeii (Italy), and were taken from buildings that had different functions: cathedral, aqueduct, and house, respectively. Thanks to image processing and the creation of masks, it was possible to extract not only the lime signature and nature of the aggregate but also its granulometry and circularity. All this information is essential for cultural heritage research. This study shows the potential of the LIBS technique in archaeometric analysis of archaeological mortars.

Le choix des matériaux occupe une place importante dans l’élaboration du projet architectural, et détermine des orientations essentielles pour le chantier, dans la réalisation de celui-ci, son organisation, voire sa progression. Loin de se résumer à un simple descripteur ou accessoire de la stratigraphie du bâtiment, les matériaux de construction sont avant tout le reflet d’une réalité complexe du chantier à la fois matérielle et immatérielle : projet, exigences et capacité financière du commanditaire, réseaux d’échange, environnement sollicité. Leur prise en compte dans l’analyse du bâti transcende la logique stratigraphique, en épaulant celle-ci là où elle fait défaut et en replaçant la réflexion dans une vision diachronique de l’économie de la construction à une échelle régionale où, dans la majorité des cas, d’un siècle à l’autre, la même contrainte environnementale contribue significativement à façonner l’approvisionnement du chantier et le visage du futur bâtiment.La contribution s’attachera à présenter ces différents enjeux en se basant principalement sur le domaine de la maçonnerie et de la couverture.

Lime mortar is a complex mixture resulting from hardening of lime, water, and aggregates. Lime mortar was used from the time of the Roman Empire until the Industrial Revolution. The recipes used differ according to the period, geographical area of preparation, craftsman, or function. This is why the study of archaeological mortars is of such great importance in building archaeology. In this study, we used laser-induced breakdown spectroscopy (LIBS) to characterize the elemental composition of three lime mortar samples with a µ-LIBS instrument, allowing elemental image compilation. These samples originate from three different geographical locations: Angers (France), Dardilly (France), and Pompeii (Italy), and were taken from buildings that had different functions: cathedral, aqueduct, and house, respectively. Thanks to image processing and the creation of masks, it was possible to extract not only the lime signature and nature of the aggregate but also its granulometry and circularity. All this information is essential for cultural heritage research. This study shows the potential of the LIBS technique in archaeometric analysis of archaeological mortars.

Since the mid-1980s, following in-depth studies of Romanesque buildings, occasionally benefitting with objective dating, the number of edifices attributable to the eleventh century in the Loire Valley has grown considerably. Among the characteristics now taken into account, those concerning the use of materials have clarified certain aspects of the evolution of construction techniques. In the continuation of earlier practices, rubble masonry is dominant at the start of the century. The stones, regularly set and of similar size, are progressively replace by elements of irregular volume. Other, less representative types of revetment (decorative, composite, mixed, etc.) also continue to be used.But the eleventh century sees an ample development of cut stone, sometimes associated in the early decades with a revetment of regular rubble stones of homogeneous size. The cut stone adopts, after a few precursors from the ninth and tenth centuries, a veritable standardization of height, leading to a perceptible improvement in the functioning of the worksite. The length of the stones follows a single module distribution, but sometimes bi-module. The dressing of the stones with a straight cutting hammer, rough, often irregular, evolves in the last decades into a more careful treatment.

So as to complement the study of architectural form, the following article outlines the development of building techniques in Anjou and Touraine, concentrating principally on the medieval period. Until the 11th century, the most common type of masonry is of rough stone. However, the 10th and 11th centuries seem to be a key period; a time when experiments were taking place using various techniques (genuine 'petit appareil', 'appareil decoratif, 'appareil composé', 'appareil mixte', 'moyen appareil'). 'Moyen appareil' using 'tuffeau, a soft limestone, gradually took the place of rough stone, and became standard in the first half of the 12th century. Its increased use seems largely to be due to the way in which the production of dressed stone was rationalised, a process which was accomplished around the end of the 11th century at the latest. In the workshop, the prefabrication of dressed stone blocks in homogeneous series whose height corresponded to various precisely defined modules became the norm. The lengths of these blocks, though not strictly speaking standardised, were none the less also grouped around a central value. One can distinguish several stages in the development of both the extraction and the working of stone. From the 12th to the middle of the 15th century, the dimensions of dressed stone do not show any significant change; variation in length is limited and the weight of an individual stone is such that it would often allow a single workman to both carry and lay it. By the second half of the 13th century, marks cut into the wall surface appear, indicating the height of particular courses. Between the second half of the 15th century and c. 1550 a new phase of experimentation can be detected, marked by the introduction of exceptionally large stone blocks. This was then followed by a further period of rationalisation, culminating in the mid-19th century with the employment of ashlar blocks standardised in both height and length. Mortar courses, which are very thick in both rough stone and in 'petit appareil', continue to be substantial throughout the middle ages. An analysis of over 5,000 mortar samples of all ages has shown that considerable variations exist in both the composition of the aggregate and in the lime content, whatever the period under consideration.

Cet ouvrage richement illustre developpe les resultats des interventions archeologiques menees par Anne Baud et Christian Sapin de 2006 a 2013, et apporte un nouvel eclairage sur Cluny, meme si toutes les interrogations ne sont pas resolues, loin de la, comme le soulignent les auteurs. En effet, si les operations concernent 14 secteurs, seuls certains d’entre eux ont ete relativement etendus, comme dans les jardins ou la « Galerie Rouge » ; mais ils ont ete accompagnes de sondages qui ont per...

Le chantier de Charles VIII (1483-1498) au château d'Amboise se déroula entre 1492 et 1498. L'année 1495-1496 est documentée par un livre de compte concernant notamment la tour cavalière des Minimes, aujourd'hui bien conservée. L'étude croisée du bâti, du livre de compte, des pierres de taille (pétrographie et statistique), des mortiers (granulométrie et analyses de la chaux) et du badigeon recouvrant les joints a nécessité la mise en place d'une méthodologie précise, demandant de continuels échanges entre historiens de l'architecture, géologues et archéologues. Ces investigations permettent d'identifier les dénominations des pierres et le vocabulaire technique en usage à la fin du Moyen Âge. Mais bien au-delà, elles démontrent l'intervention probable d'un appareilleur, l'organisation du chantier régi en plusieurs pôles et ateliers, ainsi que son rythme très soutenu puisque, pour la seule tour, plus de 15 m de maçonneries voûtées furent élevées. Ce fut possible grâce à la connaissance empirique des matériaux qu'avaient les hommes œuvrant à la construction, à la qualité des matériaux employés et à la remarquable mise en œuvre qui en fut faite. Il en résulte un ouvrage hors du commun, d'une rare audace où quatre révolutions et demie de voûtes d'ogives montent autour d'un noyau creux.

L’ensemble monastique majeur de Fontevraud (Maine-et-Loire), a l’image d’autres abbayes emblematiques comme le Mont-Saint-Michel ou Clairvaux, a ete l’un des grands centres de detention crees par Napoleon. Il fut meme le second etablissement en importance, apres la maison centrale champenoise. Depuis 1983, les travaux de rehabilitation qui y sont menes sont accompagnes d’etudes archeologiques qui ont renouvele nos connaissances sur certains aspects de l’histoire conventuelle du site, mais aus...

Charles VIII (1483-1498) construction period in the castle at Amboise took place from 1492 to 1498. In 1495-1496, an account book was written mainly about the well-preserved Tour des Minimes, a tower one could climb up on horseback. A comparative study of the building, along with the account book, cut stones (petrography and statistics), mortars (grain size distribution and lime) and the whitewash jointing, requires a specific methodology and a constant dialogue between architectural historians, geologists, and archaeologists. he research enables to identify the name of the stones and the technical vocabulary used at the end of the middle ages. Moreover, it proves that achiefstone dresser probably worked on the tower, and that the building site was likely to have been split into several centresand workshops; and it also reveals the rhythm of work to have been intense, since for the tower only, more than 15m of vaulted masonry had been created. All this have been allowed thanks to workers with an empirical knowledge of materials, the high quality of the chosen materials and the remarkable implementation they did. It resulted in an outstanding genuine edifice in which four revolutions and a half climb around an openwork newel.

The Carolingian abbatial church of Saint-Philbert-de-Grandlieu. The chevet and its reworkings At the end of the nineteenth century, when the question arose as to whether to restore the abbey church of Saint-Philbert-de-Grandlieu, it was decided to build a new parish church and to convert the old building into a covered market. At the time, Léon Maître, archivist for the lower Loire valley, studied the monument, which he dated to the Carolingian period on the basis of a text written in the ninth century by the monk Ermentaire recounting the transfer in 836 of the relics of St Philibert from Herio (Noirmoutier) to Deas (Saint-Philbert-de-Grandlieu), because of the Viking threat. In the Miracula Ermentaire briefly describes the placement of the sarcophagus in the transept of the abbey and the partial reconstruction of the chevet. The excavations made by Père de la Croix indicated the structure of the monument, but some of his interpretations were immediately contested, notably by Léon Maître and Robert de Lasteyrie. In 1960, Pierre Lebouteux made a close analysis of the masonry, but could not arrive at a conclusion concerning the structure and date of the building without further excavations. On the basis of soundings and a new reading of the construction in 1997, the chevet of the abbey church was attributed without any doubt to the Carolingian period. The nave, rebuilt in the eleventh century, preserves only a few earlier elements. Two Carolingian phases came to light. The first, probably in the early ninth century, concerns the transept and foundation works discovered in the excavations, which revealed a polygonal apse, enveloped by a narrow corridor for circulation that led to a small rectangular eastern oratory. In the second phase, after 836 and before 858 (abandonment of Deas), the chevet was enlarged, with a deep semicircular apse, on a raised platform ; underneath was a confessional crypt with the sarcophagus of Saint Philibert and a small cruciform oratory, all of which are preserved in large part. On the periphery was built an important exterior crypt with three chapels at the east end. Radio-carbon dating, analysis of architectural terracottas, archaeomagnetic and thermoluminescent datings all confirm an attribution to the Carolingian period for the two phases.

At the end of the nineteenth century, when the question arose as to whether to restore the abbey church of Saint-Philbert-de-Grandlieu, it was decided to build a new parish church and to convert the old building into a covered market. At the time, Leon Maitre, archivist for the lower Loire valley, studied the monument, which he dated to the Carolingian period on the basis of a text written in the ninth century by the monk Ermentaire recounting the transfer in 836 of the relics of St Philibert from Herio (Noirmoutier) to Dear (Saint-Philbert-de-Grancllieu), because of the Viking threat. In the Miracula Ermentaire briefly describes the placement of the sarcophagus in the transept of the abbey and the partial reconstruction of the chevet. The excavations made by Pere de la Croix indicated the structure of the monument, but some of his interpretations were immediately contested, notably by Leon Maitre and Robert de Lasteyrie. In 1960, Pierre Lebouteux made a close analysis of the masonry, but could not arrive at a conclusion concerning the structure and date of the building without further excavations. On the basis of soundings and a new reading of the construction in 1997, the chevet of the abbey church was attributed without any doubt to the Carolingian period. The nave, rebuilt in the eleventh century, preserves only a few earlier elements. Two Carolingian phases came to light. The first, probably in the early ninth century, concerns the transept and foundation works discovered in the excavations, which revealed a polygonal apse, enveloped by a narrow corridor for circulation that led to a small rectangular eastern oratory. In the second phase, after 836 and before 858 (abandonment of Deas), the chevet was enlarged, with a deep semicircular apse, on a raised platform; underneath was a confessional crypt with the sarcophagus of Saint Philibert and a small cruciform oratory, all of which are preserved in large part. On the periphery was built an important exterior crypt with three chapels at the east end. Radio-carbon dating, analysis of architectural terracottas, archaeomagnetic and thermoluminescent datings all confirm an attribution to the Carolingian period for the two phases.

Lors de l’étude menée sur l’abbatiale de Saint-Philbert de Grandlieu, l’homogénéité apparente des maçonneries du chevet a fréquemment rendu particulièrement ardue la lecture stratigraphique. Le recours à des analyses plus approfondies des matériaux a alors révélé son efficacité pour éprouver certaines hypothèses émises à partir des observations réalisées sur le site. Moellons, claveaux, pierres de taille et briques présentent des variations, parfois significatives, contribuant également à mieux caractériser les techniques carolingiennes de mise en oeuvre. Mais ce sont surtout les analyses granulométriques de l’agrégat des mortiers qui ont permis de mieux définir les étapes successives de la construction, et proposer l’association de certaines maçonneries physiquement séparées.

This study focuses on early medieval buildings in England and France, specifically on those displaying the presence of brick in their masonry. The purpose was to determine whether medieval builders reused salvaged Roman building materials or if the bricks used were contemporary to the building under construction. Thus, luminescence dating was applied to bricks sampled from 11 standing Anglo-Saxon or Carolingian churches. The luminescence dates show that the two types of practice were in use in both countries. Where contemporary brickmaking appears to be the case, the study also provided a more precise chronology of the buildings.