. Hygrothermal models are important tool for assessing the risk of moisture-related decay mechanisms in historic masonry structures. However, there are significant uncertainties in the process related to material properties, boundary conditions and quality of construction that effect confidence in the model’s predictions compared to measured values. This paper examines one potential source of uncertainty; the imperfect nature of mortar joints in masonry walls, exemplified by such things as open joints, hairline cracks and imperfect bonds at the interface between mortar and unit. These are rarely considered in hygrothermal modelling in detail, where perfect interfaces are typically inferred. The premise is that at this interface, liquid transport behaviour is more similar to that of a fracture than that of a bundle of capillaries. These fractures of varying heights (or aperture) can affect transport into and out of the plane of the wall (perpendicular plane) and impede the liquid transport between mortar and the masonry unit (in-plane). This could lead to the “effective” moisture transport being different than what would be predicted using measured bulk material properties. A more detailed method for modelling this interface, borrowing techniques from the field of geohydrology is presented which demonstrates the effect that detailed modelling of the mortar joint has on moisture transport in masonry. A brick wall with cement mortar is studied. A two-dimensional hygrothermal model was created to demonstrate the effect of increased liquid conductivity into the wall cause by fractures.
{"title":"Detailed Modelling of the Masonry Unit-Mortar Interface Using Hygrothermal Simulation","authors":"M. Gutland, S. Bucking, M. S. Quintero","doi":"10.23967/dbmc.2020.223","DOIUrl":"https://doi.org/10.23967/dbmc.2020.223","url":null,"abstract":". Hygrothermal models are important tool for assessing the risk of moisture-related decay mechanisms in historic masonry structures. However, there are significant uncertainties in the process related to material properties, boundary conditions and quality of construction that effect confidence in the model’s predictions compared to measured values. This paper examines one potential source of uncertainty; the imperfect nature of mortar joints in masonry walls, exemplified by such things as open joints, hairline cracks and imperfect bonds at the interface between mortar and unit. These are rarely considered in hygrothermal modelling in detail, where perfect interfaces are typically inferred. The premise is that at this interface, liquid transport behaviour is more similar to that of a fracture than that of a bundle of capillaries. These fractures of varying heights (or aperture) can affect transport into and out of the plane of the wall (perpendicular plane) and impede the liquid transport between mortar and the masonry unit (in-plane). This could lead to the “effective” moisture transport being different than what would be predicted using measured bulk material properties. A more detailed method for modelling this interface, borrowing techniques from the field of geohydrology is presented which demonstrates the effect that detailed modelling of the mortar joint has on moisture transport in masonry. A brick wall with cement mortar is studied. A two-dimensional hygrothermal model was created to demonstrate the effect of increased liquid conductivity into the wall cause by fractures.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115267543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ice is one of the few substances on Earth that expands when it freezes. Consequently, this phase change causes damage to porous cementitious materials that absorb water and undergo freezethaw cycling. Inspired by nature, the objective of this work is to characterize biomimetic antifreeze polymers (BAPs) that explicitly mimic the behavior of antifreeze proteins (AFPs) and antifreeze glycoproteins (AFGPs) naturally found in plants, fish, insects, and bacteria for use as a concrete additive. The ultimate goal of this work is to enhance the freeze-thaw durability of ordinary portland cement (OPC) concrete without the use of traditional air entraining agents (AEAs). This work will highlight recent research that has shown that small additions, less than 0.1% by wt. of cement, of BAPs that exhibit ice recrystallization inhibition (IRI) activity can mitigate freeze-thaw damage in OPC paste and concrete while entraining less than 3% air.
{"title":"Biomimetic Antifreeze Polymers: A Natural Solution to Freeze-Thaw Damage in Cement and Concrete","authors":"Mohammad G. Matar, Shane D. Frazier, W. Srubar","doi":"10.23967/dbmc.2020.176","DOIUrl":"https://doi.org/10.23967/dbmc.2020.176","url":null,"abstract":"Ice is one of the few substances on Earth that expands when it freezes. Consequently, this phase change causes damage to porous cementitious materials that absorb water and undergo freezethaw cycling. Inspired by nature, the objective of this work is to characterize biomimetic antifreeze polymers (BAPs) that explicitly mimic the behavior of antifreeze proteins (AFPs) and antifreeze glycoproteins (AFGPs) naturally found in plants, fish, insects, and bacteria for use as a concrete additive. The ultimate goal of this work is to enhance the freeze-thaw durability of ordinary portland cement (OPC) concrete without the use of traditional air entraining agents (AEAs). This work will highlight recent research that has shown that small additions, less than 0.1% by wt. of cement, of BAPs that exhibit ice recrystallization inhibition (IRI) activity can mitigate freeze-thaw damage in OPC paste and concrete while entraining less than 3% air.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133929581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. Vegetated facade systems (VFS) have been used as green building envelope systems in recent years. Using VFS for ecological strategies and evaluating thermal performance of these sytems are not a new concept. However, there is not any experimental study in literature which evaluates thermal performance of felt type VFS applied on an insulated existing building wall which is located in Csa climate during cooling and heating periods. Hence, an experimental study was conducted to measure thermal performance of felt type (type which used felt material as growing media) VFS in Kocaeli (under Csa climate). Test results indicate that in day time with high amount of solar radiation, felt type VFS decreased exterior surface temperatures of an insulated existing wall by maximum of 30°C. Also, interior surface temperatures of vegetated facade were lower than interior surface temperatures of reference facade with the maxiumum difference of 1.8 °C. Although high differences between exterior surface temperatures of vegetated and reference walls were observed, there was no significant difference between interior surface temperatures of vegetated and reference walls. This is due to the fact that existing building exterior wall assembly includes 5 cm thickness expanded thermal insulation material which enchance thermal performance of brick wall. In addition, indoor air temperatures behind both facades were close to each other, and were not suitable according to ISO 7730 and ASHRAE 55 Standards comfort range for representative summer days with high ambient air temperatures. Nevertheless, indoor air temperatures behind vegetated facade were in the comfort range in the fall representative day which required cooling, while indoor air temperatures behind reference facade were not in the comfort range in summer representative day.
{"title":"An Experimental Evaluation of the Thermal Performance of Felt Type Vegetated Facade System","authors":"E. Yüksel, Nil Türkeri","doi":"10.23967/dbmc.2020.006","DOIUrl":"https://doi.org/10.23967/dbmc.2020.006","url":null,"abstract":". Vegetated facade systems (VFS) have been used as green building envelope systems in recent years. Using VFS for ecological strategies and evaluating thermal performance of these sytems are not a new concept. However, there is not any experimental study in literature which evaluates thermal performance of felt type VFS applied on an insulated existing building wall which is located in Csa climate during cooling and heating periods. Hence, an experimental study was conducted to measure thermal performance of felt type (type which used felt material as growing media) VFS in Kocaeli (under Csa climate). Test results indicate that in day time with high amount of solar radiation, felt type VFS decreased exterior surface temperatures of an insulated existing wall by maximum of 30°C. Also, interior surface temperatures of vegetated facade were lower than interior surface temperatures of reference facade with the maxiumum difference of 1.8 °C. Although high differences between exterior surface temperatures of vegetated and reference walls were observed, there was no significant difference between interior surface temperatures of vegetated and reference walls. This is due to the fact that existing building exterior wall assembly includes 5 cm thickness expanded thermal insulation material which enchance thermal performance of brick wall. In addition, indoor air temperatures behind both facades were close to each other, and were not suitable according to ISO 7730 and ASHRAE 55 Standards comfort range for representative summer days with high ambient air temperatures. Nevertheless, indoor air temperatures behind vegetated facade were in the comfort range in the fall representative day which required cooling, while indoor air temperatures behind reference facade were not in the comfort range in summer representative day.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129177931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. In natural marine exposures, the chloride profile may have a maximum in the concrete surface (surface concentration) or this maximum may appear some mm or even centimeters, in depth. This fact has been attributed to a) a “washing effect” due the continuous action of the sea water, b) the wet and dry “convection” induced by the action of the sea water waves c) the leaching of the hydroxide ions or d) the carbonation of the external layer of concrete. In a test in the laboratory, the profile resulting in a diffusion chloride test in most of the cases presents the maximum in the surface of the specimen but seldom has this maximum beyond the surface. This behaviour in natural and in laboratory conditions, although noticed, has not been satisfactorily explained. The author has addressed the problem in a previous communication. In present one shows evidences on the role of the carbonates/bicarbonates in the water of the testing solution. It can be deduced from the analysis of the profiles obtained with de-carbonated solutions that the carbonates/bicarbonates ions compete with the chlorides in the binding with the hydrated cement phases, which results in a modification of the chloride profile and a different diffusion coefficient. The maximum seems to be produced by the higher mobility of the chloride with respect to the carbonate/bicarbonate. The bound chlorides are displaced by the carbonation and the free chlorides move inside forward. In the external parts less total chlorides are noticed because the free chlorides are function of the bound chlorides.
{"title":"Carbonation Effect on the Chloride Profile","authors":"C. Andrade","doi":"10.23967/dbmc.2020.232","DOIUrl":"https://doi.org/10.23967/dbmc.2020.232","url":null,"abstract":". In natural marine exposures, the chloride profile may have a maximum in the concrete surface (surface concentration) or this maximum may appear some mm or even centimeters, in depth. This fact has been attributed to a) a “washing effect” due the continuous action of the sea water, b) the wet and dry “convection” induced by the action of the sea water waves c) the leaching of the hydroxide ions or d) the carbonation of the external layer of concrete. In a test in the laboratory, the profile resulting in a diffusion chloride test in most of the cases presents the maximum in the surface of the specimen but seldom has this maximum beyond the surface. This behaviour in natural and in laboratory conditions, although noticed, has not been satisfactorily explained. The author has addressed the problem in a previous communication. In present one shows evidences on the role of the carbonates/bicarbonates in the water of the testing solution. It can be deduced from the analysis of the profiles obtained with de-carbonated solutions that the carbonates/bicarbonates ions compete with the chlorides in the binding with the hydrated cement phases, which results in a modification of the chloride profile and a different diffusion coefficient. The maximum seems to be produced by the higher mobility of the chloride with respect to the carbonate/bicarbonate. The bound chlorides are displaced by the carbonation and the free chlorides move inside forward. In the external parts less total chlorides are noticed because the free chlorides are function of the bound chlorides.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114627204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. Structural changes taking place in buildings and structures due to the passage of time are a normal phenomenon. However, the building objects are also adversely affected by atmospheric conditions or violent natural phenomena. Every year, our surroundings are increasingly attacked by extreme weather phenomena such as: floods, hurricanes, heavy storms with rain or extreme heat. Such phenomena are natural elements of nature, however they significantly interfere in the technical condition of the building. They often cause measurable economic losses: flooding, cracks, construction displacements and even their total destruction. At the time of estimating losses, calculating the costs of repair, and then making decisions about the method of restoration, a helpful tool can be laser scanning: terrestrial, airborne or mobile, depending on the character of the object and the size of the disaster. The paper presents an identification of defects and hazards in structures based on the point cloud using the OptD method.
{"title":"Identification of Defects and Hazards in Structures Based on the Point Cloud Using the OptD Method","authors":"W. Błaszczak-Bąk, J. Janicka","doi":"10.23967/dbmc.2020.188","DOIUrl":"https://doi.org/10.23967/dbmc.2020.188","url":null,"abstract":". Structural changes taking place in buildings and structures due to the passage of time are a normal phenomenon. However, the building objects are also adversely affected by atmospheric conditions or violent natural phenomena. Every year, our surroundings are increasingly attacked by extreme weather phenomena such as: floods, hurricanes, heavy storms with rain or extreme heat. Such phenomena are natural elements of nature, however they significantly interfere in the technical condition of the building. They often cause measurable economic losses: flooding, cracks, construction displacements and even their total destruction. At the time of estimating losses, calculating the costs of repair, and then making decisions about the method of restoration, a helpful tool can be laser scanning: terrestrial, airborne or mobile, depending on the character of the object and the size of the disaster. The paper presents an identification of defects and hazards in structures based on the point cloud using the OptD method.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"92 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134518054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bart Craeye, Daan van Keijzerswaard, Patricia Kara De Maeijer
. For rehabilitation of existing concrete structures, strength and durability related properties of the reinforced element are of high importance. Assessment of these properties of existing structures can be performed by (i) destructive testing of drilled cores and testing the extracted samples in lab environment and (ii) indirect methods by using non- or semi-destructive techniques on site. The use of core-drilling is a time-consuming and labour-intensive method that weakens the existing concrete structure, leaving a lasting impression on it. As an alternative, many different non and semi-destructive techniques are available for the in-situ determination of compressive strength and durability related properties. An experimental program is conducted on concrete slabs of different strength classes intended for various exposure classes (according to EN206), based on a limestone aggregate matrix, which is typically used for Belgian applications. The plates have an age of approximately 5 years, which were also characterized at younger stage (in 2014). Besides destructive core drilling and testing (compressive strength tests, chloride migration testing, and determination of carbonation rate), several non-destructive techniques were selected for this study: the rebound hammer, the ultrasonic pulse velocity tester, the Wenner probe for concrete resistivity and the air permeability tester. Best fit correlations between the output of these different techniques were established. The effect of age (e.g. carbonation) on the established predictive models is being evaluated. Strength, Durability, Transport Properties, Age Effect.
{"title":"Comparative Study on (Non-)Destructive Techniques for On-Site Strength and Durability Assessment of Limestone Based Concrete Slabs","authors":"Bart Craeye, Daan van Keijzerswaard, Patricia Kara De Maeijer","doi":"10.23967/DBMC.2020.022","DOIUrl":"https://doi.org/10.23967/DBMC.2020.022","url":null,"abstract":". For rehabilitation of existing concrete structures, strength and durability related properties of the reinforced element are of high importance. Assessment of these properties of existing structures can be performed by (i) destructive testing of drilled cores and testing the extracted samples in lab environment and (ii) indirect methods by using non- or semi-destructive techniques on site. The use of core-drilling is a time-consuming and labour-intensive method that weakens the existing concrete structure, leaving a lasting impression on it. As an alternative, many different non and semi-destructive techniques are available for the in-situ determination of compressive strength and durability related properties. An experimental program is conducted on concrete slabs of different strength classes intended for various exposure classes (according to EN206), based on a limestone aggregate matrix, which is typically used for Belgian applications. The plates have an age of approximately 5 years, which were also characterized at younger stage (in 2014). Besides destructive core drilling and testing (compressive strength tests, chloride migration testing, and determination of carbonation rate), several non-destructive techniques were selected for this study: the rebound hammer, the ultrasonic pulse velocity tester, the Wenner probe for concrete resistivity and the air permeability tester. Best fit correlations between the output of these different techniques were established. The effect of age (e.g. carbonation) on the established predictive models is being evaluated. Strength, Durability, Transport Properties, Age Effect.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"101 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122136887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article describes testing of peel and shear resistance and airtightness of joints of air and vapour barrier systems before and after artificial aging. The testing of peel and shear resistance was based on standardised methods while the test of airtightness was a method invented for this project. The results show that while peel and shear strength increased with aging, the airtightness was significantly reduced. As these two results seem to contradict each other, the methods are discussed, especially whether the standardised tests are too far from the conditions on site or joints should be tested on other materials as well. Furthermore, weaknesses in the airtightness method is also pointed out.
{"title":"Testing Joints of Air and Vapour Barriers, Do We Use Relevant Testing Methods?","authors":"E. Møller, T. V. Rasmussen","doi":"10.23967/DBMC.2020.135","DOIUrl":"https://doi.org/10.23967/DBMC.2020.135","url":null,"abstract":"This article describes testing of peel and shear resistance and airtightness of joints of air and vapour barrier systems before and after artificial aging. The testing of peel and shear resistance was based on standardised methods while the test of airtightness was a method invented for this project. The results show that while peel and shear strength increased with aging, the airtightness was significantly reduced. As these two results seem to contradict each other, the methods are discussed, especially whether the standardised tests are too far from the conditions on site or joints should be tested on other materials as well. Furthermore, weaknesses in the airtightness method is also pointed out.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130214752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. Rainwater and moisture control are key factors for maintaining the durability of wooden houses. Wall assemblies with sidings are installed on vented cavities to build durable wooden houses. Moisture condensation does not occur generally behind a vapor retarder in walls assembled with a vented cavity; however, it is reported that the condensation mechanism which occurs in the wall assembly due to the high humidity of the vented cavity by rain penetration in Japan, there are only a few studies that investigate hygrothermal behaviour considering effects such as rain penetration in the exterior system. To unravel the mechanism of internal condensation derived from rain penetration, lab-experiments and field measurements were conducted. In the lab experiments, rain penetration from siding joints were quantitated using a water spray test. In the field measurements, for the exterior finishes of the experimental house, the sidings were installed on three types of vented cavities. To verify hygrothermal behavior within the wall assembly, intermittent long-term rain penetration into the vented cavity was reproduced for the experimental house. The measurements confirmed that internal condensation occurs with low ventilation performance, when moisture retained in the vented cavity is released into the wall assembly. This phenomenon is caused when the surface temperature on the sidings is increased because of solar radiation after rain. In conclusion, rain penetration through exterior finishes has a significant effect on the moisture behavior of wall assemblies. The obtained results verify that moisture condensation at the vapor retarder was caused by several factors including rain penetration, insufficient ventilation, and solar radiation. To maintain durability, it is important to ensure a ventilation performance and not retain moisture.
{"title":"Field Survey of Hygrothermal Behaviour within Wall Assembly Derived from Rain Penetration and Ventilation Performance of Exterior System","authors":"Sadaharu Osamura, Hiroaki Saito","doi":"10.23967/DBMC.2020.068","DOIUrl":"https://doi.org/10.23967/DBMC.2020.068","url":null,"abstract":". Rainwater and moisture control are key factors for maintaining the durability of wooden houses. Wall assemblies with sidings are installed on vented cavities to build durable wooden houses. Moisture condensation does not occur generally behind a vapor retarder in walls assembled with a vented cavity; however, it is reported that the condensation mechanism which occurs in the wall assembly due to the high humidity of the vented cavity by rain penetration in Japan, there are only a few studies that investigate hygrothermal behaviour considering effects such as rain penetration in the exterior system. To unravel the mechanism of internal condensation derived from rain penetration, lab-experiments and field measurements were conducted. In the lab experiments, rain penetration from siding joints were quantitated using a water spray test. In the field measurements, for the exterior finishes of the experimental house, the sidings were installed on three types of vented cavities. To verify hygrothermal behavior within the wall assembly, intermittent long-term rain penetration into the vented cavity was reproduced for the experimental house. The measurements confirmed that internal condensation occurs with low ventilation performance, when moisture retained in the vented cavity is released into the wall assembly. This phenomenon is caused when the surface temperature on the sidings is increased because of solar radiation after rain. In conclusion, rain penetration through exterior finishes has a significant effect on the moisture behavior of wall assemblies. The obtained results verify that moisture condensation at the vapor retarder was caused by several factors including rain penetration, insufficient ventilation, and solar radiation. To maintain durability, it is important to ensure a ventilation performance and not retain moisture.","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114978447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
. In this study, the comparison of lava sand, pumice, and natural zeolite as lightweight aggregate in air lime mortars, natural hydraulic lime mortars, and cement-lime mortars has been investigated with emphasis on the resistance of salt and ice crystallization. The lava sand and pumice improved frost resistance of the mortars while natural zeolite mortars remained without this effect due to their high water absorption. Salt crystallization resistance of the mortars was improved by using lava sand and natural pumice, while the mortars with natural zeolite were not resistant to crystallization of sodium chloride. The mortars have relatively little resistance to the reacting of Na 2 SO 4 , where gypsum and calcium sulfoaluminates were formed breaking the structure of the mortars. The best results were obtained using natural pumice .
{"title":"Salt and Ice Crystallization Resistance of Lime Mortars with Natural Lightweight Aggregate","authors":"M. Vyšvařil, P. Bayer","doi":"10.23967/DBMC.2020.121","DOIUrl":"https://doi.org/10.23967/DBMC.2020.121","url":null,"abstract":". In this study, the comparison of lava sand, pumice, and natural zeolite as lightweight aggregate in air lime mortars, natural hydraulic lime mortars, and cement-lime mortars has been investigated with emphasis on the resistance of salt and ice crystallization. The lava sand and pumice improved frost resistance of the mortars while natural zeolite mortars remained without this effect due to their high water absorption. Salt crystallization resistance of the mortars was improved by using lava sand and natural pumice, while the mortars with natural zeolite were not resistant to crystallization of sodium chloride. The mortars have relatively little resistance to the reacting of Na 2 SO 4 , where gypsum and calcium sulfoaluminates were formed breaking the structure of the mortars. The best results were obtained using natural pumice .","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"118 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116356589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Palace of Westminster, commonly known as the Houses of Parliament, serves as the meeting place of the House of Commons and the House of Lords and is situated on the north bank of the River Thames in London, England. The site is part of the UNESCO Westminster World Heritage Site. The building was constructed of magnesian limestone, selected following a nationwide survey of building stones carried out by a Government Select Committee. However, some of this stone began to decay soon after construction in the mid 1800s. As the majority of the stonework has survived very well the aim of the work was to source a demonstrably durable material with characteristics which align with the majority of the existing stonework. Samples were taken from the building for petrographic analysis in order to identify compatible material in quarries, either working or which could be re-opened. Durability of the magnesian limestone was assessed using both accepted tests and novel methodology. Large scale walls were constructed in the laboratory and exposed to accelerated frost weathering with realistic temperature parameters. The logistical problems with sourcing the original building material, the nature of the transport and the masons' unfamiliarity with the stone may all have played a part in undermining its durability. When magnesian limestone is properly selected and used correctly, its reputation for being of poor durability is largely unfounded. Suitable sources for replacement stone were located which provided several options for both immediate and long-term sourcing for repair and conservation
{"title":"The Palace of Westminster Courtyards Project: Sourcing Stone for Repair and Conservation","authors":"E. Laycock, D. Jefferson, S. Hetherington","doi":"10.23967/DBMC.2020.152","DOIUrl":"https://doi.org/10.23967/DBMC.2020.152","url":null,"abstract":"The Palace of Westminster, commonly known as the Houses of Parliament, serves as the \u0000meeting place of the House of Commons and the House of Lords and is situated on the north bank of the \u0000River Thames in London, England. The site is part of the UNESCO Westminster World Heritage Site. \u0000The building was constructed of magnesian limestone, selected following a nationwide survey of building \u0000stones carried out by a Government Select Committee. However, some of this stone began to decay soon \u0000after construction in the mid 1800s. As the majority of the stonework has survived very well the aim of \u0000the work was to source a demonstrably durable material with characteristics which align with the \u0000majority of the existing stonework. Samples were taken from the building for petrographic analysis in \u0000order to identify compatible material in quarries, either working or which could be re-opened. Durability \u0000of the magnesian limestone was assessed using both accepted tests and novel methodology. Large scale \u0000walls were constructed in the laboratory and exposed to accelerated frost weathering with realistic \u0000temperature parameters. The logistical problems with sourcing the original building material, the nature \u0000of the transport and the masons' unfamiliarity with the stone may all have played a part in undermining \u0000its durability. When magnesian limestone is properly selected and used correctly, its reputation for being \u0000of poor durability is largely unfounded. Suitable sources for replacement stone were located which \u0000provided several options for both immediate and long-term sourcing for repair and conservation","PeriodicalId":409611,"journal":{"name":"XV International Conference on Durability of Building Materials and Components. eBook of Proceedings","volume":"117 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117310761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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