This paper presents an approach to the use and interpretation of tests on mortar samples when res... more This paper presents an approach to the use and interpretation of tests on mortar samples when restoring historic masonry. It is largely based on the work performed by the former RILEM technical committee 167-COM, Characterisation of old mortars, closed in 2003, and the ongoing committee 203-RHM, Repair mortars for historic masonry. The focus of the present paper is on the decision process: what to test and how to interpret the test results.
This paper deals with the new findings regarding techniques of Renaissance sgraffito. In the atti... more This paper deals with the new findings regarding techniques of Renaissance sgraffito. In the attic of a Renaissance castle in Telč in Southern Bohemia, unrestored Renaissance sgraffiti having an unexpected appearance (softly shaded, with a deep illusion of modelling) were found. The sgraffiti were thoroughly examined in situ and samples were taken. After the results of individual research activities had been combined, the apparent original process of this particular sgraffito technique was reconstructed in theory. Subsequently, the process was experimentally verified on specimen panels. A great deal of the Renaissance sgraffiti in the Czech Republic underwent extensive restoration interventions in the twentieth century. In these cases, surface traces were altered and therefore it is very difficult to prove scientifically the way they were originally finished. However, on the basis of our experience with sgraffiti (which allowed a more detailed examination during their restoration pr...
V soucasne době již velký pocet střednich, ale i zakladnich skol použiva měřici system ISES. Ten ... more V soucasne době již velký pocet střednich, ale i zakladnich skol použiva měřici system ISES. Ten lze použit nejen při výuce fyziky a dalsich přirodnich věd, ale i ve vztahu k poznavani lidskeho těla. Měřeni tělesne teploty, tepu, elektrickeho odporu lidskeho těla, a dalsich velicin ve výuce rozsiři žakům přehled o lidskem těle a možných zdravotnich ukazatelich. Žak bude sledovan při různých tělesných i dusevnich aktivitach např.: leh, dřepy, sed – vztyk, řeseni ulohy, hadanek, hra na PC. System ISES umožňuje jednoduchým způsobem měnit měřici moduly (teploty, tepu, EKG-metr). Měřene veliciny lze v realnem case sledovat na monitoru PC. Naměřena data lze uchovavat pro dalsi zpracovani. Vhodne je zařazeni do vzdělavaci oblasti Informacni a komunikacni technologie, Clověk a jeho svět, Clověk a přiroda (Fyzika, Chemie, Přirodopis), Clověk a zdravi (Výchova ke zdravi). V ramci projektu jsme navrhli dvě laboratorni ulohy, využivajici system ISES. Při vlastni výuce mohou žaci sami ulohy sest...
ABSTRACT A high relief stucco decoration from the Great Chamber of the castle Červená Lhota in th... more ABSTRACT A high relief stucco decoration from the Great Chamber of the castle Červená Lhota in the Southern Bohemia was surveyed and characterised as a part of its planned conservation. A detailed analytical work was undertaken in order to provide support for the repair works that aimed to be based on a good knowledge of the original materials and application techniques. The main research focus was on the fruit pieces decorating the ribs of vaults. Altogether, over 20 mortar samples were collected from the vault bedding mortar, plaster, stucco elements and the stucco pieces themselves. Additionally, some pieces of stucco (fruits), that were loose and had to be temporarily removed, were studied macroscopically and by X-ray CT. The characterisation of binder, aggregate and additives was carried out using OM, SEM, TA, acid attack, sieve analysis of insoluble residue, XRD, FTIR and nL-MS. It led to an understanding of the uses of various mortar mixes and determination of their composition. The results are discussed as an example of an analytical procedure that aimed at understanding in detail of this historically significant technique from a material and technological standpoint.
Abstract Lime binders are utilised worldwide and are associated with a considerable scale of prod... more Abstract Lime binders are utilised worldwide and are associated with a considerable scale of production and corresponding CO2 emissions. The relevance of this review is therefore international in scope, with production transcending geographical boundaries and construction practices. An holistic view of lime binders, considering their provenance, production and utilisation offers the potential for significant CO2 savings urgently required globally. Importantly, the technical aspects of lime materials production is critical, but the alteration of behaviour of both specifier and those undertaking the construction processes is also essential in achieving meaningful CO2 emission reduction. This review paper investigates the life cycle stages of lime binders in line with the features highlighted in the Scottish Building Alliance (SBA) ‘building life cycle stages model’. It attempts to determine what can be learnt from our understanding of the manufacture and use of binders from historic, current and future perspectives in the context of reconciling the production of historically authentic materials in a decarbonising environment. The production and use of such authentic historic lime binders initially appears highly carbon intensive through its utilisation of relatively inefficient kiln technologies and loss of economies of scale associated with larger operations. However, this review shows numerous benefits in the production of such binders; including their CO2 sequestration capability, lower potential processing energy, and a reduction in excessive ‘carbon miles’ associated with transportation. Importantly, we show how historic production and on-site manufacture approaches with lime-based materials also offers exciting potential for carbon savings. Importantly, hot mixed lime mortars offer the promise of higher durability materials compared to their modern cold manufactured counterparts, thereby reducing the frequency of repeat maintenance interventions, again yielding CO2 savings. We suggest hot mixing, whether in an innovative contemporary materials realm or within traditional contexts should be explored. In addition, hot mixed materials can concomitantly satisfy conservation requirements for repairs through better reflecting the aspired to building conservation requirement of like for like materials replacement reflected with historically produced binders. We suggest future paths for the industry that would simultaneously reconcile demands for authentic materials and production methods for the conservation sector with the necessity of achieving cleaner production in a decarbonizing world.
Surface repair mortars are used for the compensation, or repair, of lost portions of surface mate... more Surface repair mortars are used for the compensation, or repair, of lost portions of surface materials in historic masonry buildings. It is recommended that their design and application should be performed in a wider context of conservation values related decision making, to prioritise preservation of original fabric, authenticity of approach and maintenance of integrity, and not just on technical principles alone. However, a technical context for their design does exist, that requires understanding of the properties of the substrate that they will be applied onto, and adherence to minimum aesthetic (colour and texture) requirements. The principles of physical, mechanical and chemical compatibility of repair apply and the attributes of the repair mortar should be carefully matched to the substrate alongside a sacrificial behaviour (not more durable than the material being replaced). Guidance is given on the design, application and the functional requirements that must be met when using surface repair mortars. Keywords Surface repair Á Mortar Á Historic masonry Á Functional requirements 1 Introduction This document deals with mortars used for the repair of historic stone and brick substrates. Various terms, referring to the same or very similar interventions of surface repair are in use, such as mortar repair, plastic repair, surface fill, loss compensation mortar repair, stone imitation, stone patch [1-4]. What these repair methods have in common is that a missing part of an This publication was written within the framework of RILEM Technical Committee 243-SGM, with contributions of the following TC members:
h i g h l i g h t s NHL was produced in a laboratory furnace in temperature range from 850 to 120... more h i g h l i g h t s NHL was produced in a laboratory furnace in temperature range from 850 to 1200°C. The major hydraulic component was b-C2S, around 40 wt.%. Lower calcination temperatures led to formation of amorphous phases. The higher calcination temperature, the lower the reactivity and slaking residue. Recommended optimal calcination temperature was between 1000 and 1100°C.
There has been an increasing interest in the reproduction of natural hydraulic limes, as they are... more There has been an increasing interest in the reproduction of natural hydraulic limes, as they are considered an appropriate material for conservation and restoration of historic buildings. This study assessed the influence of different calcination temperatures (850–1200 �C) on the mineralogical composition and the reactivity of quicklime, as well as the setting time and the mechanical performance of mortar specimens. The limestone was acquired from a single quarry and contained 8.7% SiO2, 45% CaO. The results of XRPD and slaking reactivity of the produced quicklime confirmed a clear dependency on the calcination temperature. The performance properties of mortars made with the produced lime did not demonstrate a clear relation to the calcination temperature. The experiment confirmed that calcination temperatures from 850 to 1200 �C can be used to produce natural hydraulic lime from the selected limestone. The optimal calcination temperature range from 1000 to 1100 �C is recommended
Reconstruction of a ceiling in the north-eastern wing of a former water fortress in Jeseník was c... more Reconstruction of a ceiling in the north-eastern wing of a former water fortress in Jeseník was carried out during the repair of its roof structure and replacement of the roof. The most damaged parts of the bearing ceiling beams were removed and partially replaced with new timber in the 70s of the 20th C. The way the work was carried out corresponded to the methods and approaches of the cultural heritage protection of that time. The replacement of damaged heads of ceiling beams with new timber that was fitted without connection to the original ceiling beams and only simply hanged on a metal girder can be considered highly provisional from the current perspective. That is why the repair of timber structures of the water fortress included also a reconstruction of the original ceiling system. Surveys focusing on the building archaeology and material assessing the condition of the incorporated timber were important for the final design of the repair and the concept of presentation of th...
Po stopách žďárského mramoru. Hledání původu surovin použitých při stavbě gotického kláštera., 2017
VÁLEK, Jan; MALÝ, Karel; GONDA, Radim; ŘIHOŠEK, Jaroslav; SKRUŽNÁ, Olga; KOVÁŘ, Miroslav: Po stop... more VÁLEK, Jan; MALÝ, Karel; GONDA, Radim; ŘIHOŠEK, Jaroslav; SKRUŽNÁ, Olga; KOVÁŘ, Miroslav: Po stopách žďárského mramoru. Hledání původu surovin použitých při stavbě gotického kláštera. Ústav teoretické a aplikované mechaniky AV ČR, v. v. i., Praha 2017. ISBN: 9788086246857
The paper attempts to connect practical problems arising from the use of lime mortars in conserva... more The paper attempts to connect practical problems arising from the use of lime mortars in conservation and the latest scientific research in transport phenomena and durability of porous materials. It identifies specific requirements and current issues, which need to be clarified from conservation practice. It also examines the scope of the problems by carrying out simple experiments on lime mortar specimens. Characteristics like gas permeability, porosity and gain of weight were determined after six months of curing. These characteristics were related to the carbonation process. Two hypotheses are suggested. First, the gas permeability of lime mortars is influenced more by surface finish than the amount of water added to the mix. Second, the carbonation process of lime mortars depends on the surface gas permeability rather than the internal gas permeability. The surface permeability is possibly the rate-determining factor.
This paper presents an approach to the use and interpretation of tests on mortar samples when res... more This paper presents an approach to the use and interpretation of tests on mortar samples when restoring historic masonry. It is largely based on the work performed by the former RILEM technical committee 167-COM, Characterisation of old mortars, closed in 2003, and the ongoing committee 203-RHM, Repair mortars for historic masonry. The focus of the present paper is on the decision process: what to test and how to interpret the test results.
This paper deals with the new findings regarding techniques of Renaissance sgraffito. In the atti... more This paper deals with the new findings regarding techniques of Renaissance sgraffito. In the attic of a Renaissance castle in Telč in Southern Bohemia, unrestored Renaissance sgraffiti having an unexpected appearance (softly shaded, with a deep illusion of modelling) were found. The sgraffiti were thoroughly examined in situ and samples were taken. After the results of individual research activities had been combined, the apparent original process of this particular sgraffito technique was reconstructed in theory. Subsequently, the process was experimentally verified on specimen panels. A great deal of the Renaissance sgraffiti in the Czech Republic underwent extensive restoration interventions in the twentieth century. In these cases, surface traces were altered and therefore it is very difficult to prove scientifically the way they were originally finished. However, on the basis of our experience with sgraffiti (which allowed a more detailed examination during their restoration pr...
V soucasne době již velký pocet střednich, ale i zakladnich skol použiva měřici system ISES. Ten ... more V soucasne době již velký pocet střednich, ale i zakladnich skol použiva měřici system ISES. Ten lze použit nejen při výuce fyziky a dalsich přirodnich věd, ale i ve vztahu k poznavani lidskeho těla. Měřeni tělesne teploty, tepu, elektrickeho odporu lidskeho těla, a dalsich velicin ve výuce rozsiři žakům přehled o lidskem těle a možných zdravotnich ukazatelich. Žak bude sledovan při různých tělesných i dusevnich aktivitach např.: leh, dřepy, sed – vztyk, řeseni ulohy, hadanek, hra na PC. System ISES umožňuje jednoduchým způsobem měnit měřici moduly (teploty, tepu, EKG-metr). Měřene veliciny lze v realnem case sledovat na monitoru PC. Naměřena data lze uchovavat pro dalsi zpracovani. Vhodne je zařazeni do vzdělavaci oblasti Informacni a komunikacni technologie, Clověk a jeho svět, Clověk a přiroda (Fyzika, Chemie, Přirodopis), Clověk a zdravi (Výchova ke zdravi). V ramci projektu jsme navrhli dvě laboratorni ulohy, využivajici system ISES. Při vlastni výuce mohou žaci sami ulohy sest...
ABSTRACT A high relief stucco decoration from the Great Chamber of the castle Červená Lhota in th... more ABSTRACT A high relief stucco decoration from the Great Chamber of the castle Červená Lhota in the Southern Bohemia was surveyed and characterised as a part of its planned conservation. A detailed analytical work was undertaken in order to provide support for the repair works that aimed to be based on a good knowledge of the original materials and application techniques. The main research focus was on the fruit pieces decorating the ribs of vaults. Altogether, over 20 mortar samples were collected from the vault bedding mortar, plaster, stucco elements and the stucco pieces themselves. Additionally, some pieces of stucco (fruits), that were loose and had to be temporarily removed, were studied macroscopically and by X-ray CT. The characterisation of binder, aggregate and additives was carried out using OM, SEM, TA, acid attack, sieve analysis of insoluble residue, XRD, FTIR and nL-MS. It led to an understanding of the uses of various mortar mixes and determination of their composition. The results are discussed as an example of an analytical procedure that aimed at understanding in detail of this historically significant technique from a material and technological standpoint.
Abstract Lime binders are utilised worldwide and are associated with a considerable scale of prod... more Abstract Lime binders are utilised worldwide and are associated with a considerable scale of production and corresponding CO2 emissions. The relevance of this review is therefore international in scope, with production transcending geographical boundaries and construction practices. An holistic view of lime binders, considering their provenance, production and utilisation offers the potential for significant CO2 savings urgently required globally. Importantly, the technical aspects of lime materials production is critical, but the alteration of behaviour of both specifier and those undertaking the construction processes is also essential in achieving meaningful CO2 emission reduction. This review paper investigates the life cycle stages of lime binders in line with the features highlighted in the Scottish Building Alliance (SBA) ‘building life cycle stages model’. It attempts to determine what can be learnt from our understanding of the manufacture and use of binders from historic, current and future perspectives in the context of reconciling the production of historically authentic materials in a decarbonising environment. The production and use of such authentic historic lime binders initially appears highly carbon intensive through its utilisation of relatively inefficient kiln technologies and loss of economies of scale associated with larger operations. However, this review shows numerous benefits in the production of such binders; including their CO2 sequestration capability, lower potential processing energy, and a reduction in excessive ‘carbon miles’ associated with transportation. Importantly, we show how historic production and on-site manufacture approaches with lime-based materials also offers exciting potential for carbon savings. Importantly, hot mixed lime mortars offer the promise of higher durability materials compared to their modern cold manufactured counterparts, thereby reducing the frequency of repeat maintenance interventions, again yielding CO2 savings. We suggest hot mixing, whether in an innovative contemporary materials realm or within traditional contexts should be explored. In addition, hot mixed materials can concomitantly satisfy conservation requirements for repairs through better reflecting the aspired to building conservation requirement of like for like materials replacement reflected with historically produced binders. We suggest future paths for the industry that would simultaneously reconcile demands for authentic materials and production methods for the conservation sector with the necessity of achieving cleaner production in a decarbonizing world.
Surface repair mortars are used for the compensation, or repair, of lost portions of surface mate... more Surface repair mortars are used for the compensation, or repair, of lost portions of surface materials in historic masonry buildings. It is recommended that their design and application should be performed in a wider context of conservation values related decision making, to prioritise preservation of original fabric, authenticity of approach and maintenance of integrity, and not just on technical principles alone. However, a technical context for their design does exist, that requires understanding of the properties of the substrate that they will be applied onto, and adherence to minimum aesthetic (colour and texture) requirements. The principles of physical, mechanical and chemical compatibility of repair apply and the attributes of the repair mortar should be carefully matched to the substrate alongside a sacrificial behaviour (not more durable than the material being replaced). Guidance is given on the design, application and the functional requirements that must be met when using surface repair mortars. Keywords Surface repair Á Mortar Á Historic masonry Á Functional requirements 1 Introduction This document deals with mortars used for the repair of historic stone and brick substrates. Various terms, referring to the same or very similar interventions of surface repair are in use, such as mortar repair, plastic repair, surface fill, loss compensation mortar repair, stone imitation, stone patch [1-4]. What these repair methods have in common is that a missing part of an This publication was written within the framework of RILEM Technical Committee 243-SGM, with contributions of the following TC members:
h i g h l i g h t s NHL was produced in a laboratory furnace in temperature range from 850 to 120... more h i g h l i g h t s NHL was produced in a laboratory furnace in temperature range from 850 to 1200°C. The major hydraulic component was b-C2S, around 40 wt.%. Lower calcination temperatures led to formation of amorphous phases. The higher calcination temperature, the lower the reactivity and slaking residue. Recommended optimal calcination temperature was between 1000 and 1100°C.
There has been an increasing interest in the reproduction of natural hydraulic limes, as they are... more There has been an increasing interest in the reproduction of natural hydraulic limes, as they are considered an appropriate material for conservation and restoration of historic buildings. This study assessed the influence of different calcination temperatures (850–1200 �C) on the mineralogical composition and the reactivity of quicklime, as well as the setting time and the mechanical performance of mortar specimens. The limestone was acquired from a single quarry and contained 8.7% SiO2, 45% CaO. The results of XRPD and slaking reactivity of the produced quicklime confirmed a clear dependency on the calcination temperature. The performance properties of mortars made with the produced lime did not demonstrate a clear relation to the calcination temperature. The experiment confirmed that calcination temperatures from 850 to 1200 �C can be used to produce natural hydraulic lime from the selected limestone. The optimal calcination temperature range from 1000 to 1100 �C is recommended
Reconstruction of a ceiling in the north-eastern wing of a former water fortress in Jeseník was c... more Reconstruction of a ceiling in the north-eastern wing of a former water fortress in Jeseník was carried out during the repair of its roof structure and replacement of the roof. The most damaged parts of the bearing ceiling beams were removed and partially replaced with new timber in the 70s of the 20th C. The way the work was carried out corresponded to the methods and approaches of the cultural heritage protection of that time. The replacement of damaged heads of ceiling beams with new timber that was fitted without connection to the original ceiling beams and only simply hanged on a metal girder can be considered highly provisional from the current perspective. That is why the repair of timber structures of the water fortress included also a reconstruction of the original ceiling system. Surveys focusing on the building archaeology and material assessing the condition of the incorporated timber were important for the final design of the repair and the concept of presentation of th...
Po stopách žďárského mramoru. Hledání původu surovin použitých při stavbě gotického kláštera., 2017
VÁLEK, Jan; MALÝ, Karel; GONDA, Radim; ŘIHOŠEK, Jaroslav; SKRUŽNÁ, Olga; KOVÁŘ, Miroslav: Po stop... more VÁLEK, Jan; MALÝ, Karel; GONDA, Radim; ŘIHOŠEK, Jaroslav; SKRUŽNÁ, Olga; KOVÁŘ, Miroslav: Po stopách žďárského mramoru. Hledání původu surovin použitých při stavbě gotického kláštera. Ústav teoretické a aplikované mechaniky AV ČR, v. v. i., Praha 2017. ISBN: 9788086246857
The paper attempts to connect practical problems arising from the use of lime mortars in conserva... more The paper attempts to connect practical problems arising from the use of lime mortars in conservation and the latest scientific research in transport phenomena and durability of porous materials. It identifies specific requirements and current issues, which need to be clarified from conservation practice. It also examines the scope of the problems by carrying out simple experiments on lime mortar specimens. Characteristics like gas permeability, porosity and gain of weight were determined after six months of curing. These characteristics were related to the carbonation process. Two hypotheses are suggested. First, the gas permeability of lime mortars is influenced more by surface finish than the amount of water added to the mix. Second, the carbonation process of lime mortars depends on the surface gas permeability rather than the internal gas permeability. The surface permeability is possibly the rate-determining factor.
This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of... more This paper aims at improving the quality of lime mortar masonry by understanding the mechanics of mortars and masonry and their interaction. It investigates how the mortar's compressive and flexural strengths impact the compressive and bond strength of clay brick masonry bound with calcium lime (CL) and natural hydraulic lime (NHL) mortars. It concludes that the strength of the bond has a greater impact on the compressive strength of masonry than the mortar's strength. The masonry compressive strength increased proportionally to the strength of the bond up to 6 months. A regression analysis, giving a second order equation with coefficient of determination (R 2 ) of 0.918, demonstrates a strong and predictable relationship between bond strength and masonry compressive strength. It was noted that CL90s mortar masonry reaching a high bond value was stronger than that built with a stronger mortar but displaying a poorer bond. Finally, the mechanics of lime mortars and their masonry are similar. The predominantly elastic behaviour of the mortars of higher hydraulic strength compares well with the elastic and brittle behaviour of their masonry, with either little (NHL2) or non existent plasticity (NHL3.5 and 5); in contrast, the CL90 mortar and masonry exhibit a plastic behaviour.
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