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Slaked lime is traditionally a suitable material for use in construction activities in historic and traditional buildings whose constitutive characteristics demand compatible and appropriate material solutions. Therefore, knowing the physical and mechanical characterization of lime pastes and mortars for use in restoration is considered an important step in the process of scientific development of a material that, in the Mexican case, has lacked scientific rigor in its production, use and commercialization. With this in mind, the present article aims to investigate the characteristics of lime pastes and mortars that have been used in the traditional way and the new limes that exist in the market, offering suitable options for restoration, for which an integrated methodology was used consisting of physical tests such as surface area, electrical resistivity, pulse velocity, colorimetry, and mechanical tests such as compressive strength, giving as a result that “traditional slaked” lime is more likely to deteriorate than powdered lime, which leads us to conclude that powdered hydrated lime has optimal characteristics for restoration activities.

This study examines the mortar materials used in the construction of the walls at the Archaeological Roman Fortification site (Ovidiu, Romania) on the shore of Siutghiol Lake. Several analyses were conducted to determine the mortars' basic physical properties, mineralogical composition, and microstructural characteristics in order to describe the mortars used in the construction of the Roman fortress. The investigation utilized X-ray diffraction (XRD), energy dispersive X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM-EDAX), and differential thermal analysis (TGA-DTA). The results indicated that siliceous aggregates and lime binders were used in the production of the studied mortars, the structure was constructed in the sixth century, and the raw materials used to construct the site are of local origin. Using the methods mentioned above, there is the possibility of recreating the fortification's mortar formula using contemporary materials and recommending intervention materials for the preservation of the archaeology of the Roman Fortification. Furthermore, this study opens up many other research opportunities regarding the reuse of mortars extracted from archaeological sites in the rehabilitation process by integrating them into new mortar recipes that can then be tested to compare the results with those obtained from standardized recipes. [ABSTRACT FROM AUTHOR]

This study examines the mortar materials used in the construction of the walls at the Archaeological Roman Fortification site (Ovidiu, Romania) on the shore of Siutghiol Lake. Several analyses were conducted to determine the mortars’ basic physical properties, mineralogical composition, and microstructural characteristics in order to describe the mortars used in the construction of the Roman fortress. The investigation utilized X-ray diffraction (XRD), energy dispersive X-ray fluorescence spectroscopy (XRF), scanning electron microscopy (SEM-EDAX), and differential thermal analysis (TGA-DTA). The results indicated that siliceous aggregates and lime binders were used in the production of the studied mortars, the structure was constructed in the sixth century, and the raw materials used to construct the site are of local origin. Using the methods mentioned above, there is the possibility of recreating the fortification’s mortar formula using contemporary materials and recommending intervention materials for the preservation of the archaeology of the Roman Fortification. Furthermore, this study opens up many other research opportunities regarding the reuse of mortars extracted from archaeological sites in the rehabilitation process by integrating them into new mortar recipes that can then be tested to compare the results with those obtained from standardized recipes.

The study of external renderings in the scope of conservation and restoration has acquired in the last years great methodological, scientific and technical advances. These renderings are important elements of the built structure, for besides possessing a protection function, they possess often a decorative function of great relevance for the image of the monument. The maintenance of these renderings implies the conservation of traditional constructive techniques and the use of compatible materials, as similar to the originals as possible. The main objective of this study is to define a methodology of conservative restoration using strategies of maintenance of renderings and traditional constructive techniques. The minimum intervention principle is maintained as well as the use of materials compatible with the original ones. This paper describes the technique and products used for the consolidation of the loss of cohesion. The testing campaign was developed under controlled conditions, in laboratory, and in situ in order to evaluate their efficacy for the consolidation of old renders. A set of tests is presented to evaluate the effectiveness of the process. The results are analysed and a reflection is added referring to the applicability of these techniques. Finally the paper presents a proposal for further research.

Intervention in ancient buildings with historical and architectural value requires traditional techniques, such as the use of lime mortars for internal and external wall renderings. In order to ensure the desired performance, these rendering mortars must be rigorously specified and quality controls have to be performed during application. The choice of mortar composition should take account of factors such as compatibility with the substrate, mechanical requirements and water behaviour. The construction schedule, which used to be considered a second order variable, nowadays plays a decisive role in the selection of the rendering technique, given its effects upon costs. How should lime-based mortars be specified? How much time is required for the application and curing of a lime-based render? This paper reflects upon the feasibility of using traditional lime mortars in three-layer renders inside churches and monasteries under adverse hygrothermal conditions and when time is critical. A case study is presented in which internal lime mortar renderings were applied in a church in Northern Portugal, where the very high relative humidity meant that several months were necessary before the drying process was complete.

Portugal is one of the European countries in which built heritage is a testimony of its history. In this context, the legacy of the decorative glazed tile coatings of facades must be preserved and restored. This research is dedicated to the conservation of such facades in the city of Ovar, considered an example due to its rich heritage in glazed tiles, a high percentage of which requires a deep intervention. Therefore, this work is focused on the study of lime renders serving as a support for this type of tile facades. For this, samples were collected from several buildings in the city, targeting their mechanical and physical study with the aim of producing compatible mortars to be used for application of detached tiles in these buildings and generally for the repair of the facades with glazed tile coatings. For this purpose, four lime mortar formulations with different volumetric ratios were composed. The aggregates used were: ordinary river sand and local gravel. In three of the mixtures, metakaolin was added, with the intention of acting as an artificial pozzolan and thus improving the performance of these mortars. The use of a pozzolanic addition promotes hardening of lime mortars in cases when the ingression of carbon dioxide is low as is the case of mortars placed below glazed tile coatings. These mortars were also tested in the laboratory taking into account their physical and mechanical characteristics. The mechanical characteristics determined were: modulus of elasticity by two different methods, compressive strength and flexural strength. In turn, the physical characteristics determined were: water vapour permeability and water absorption by total immersion and capillary action. The best mechanical behaviour (compressive and flexural) was observed in the mortar with pozzolanic additions. Similarly, the value of the modulus of elasticity was better in mortars with pozzolanic additions. The performance of these mortars was also adequate in terms of water behaviour. The mortars revealed suitable characteristics for application in building conservation situations concerning coating with glazed tiles.