Pub Date : 2024-07-16DOI: 10.3390/buildings14072192
Yuying Dou, Yongquan Chen
With the increasing demand for medical checkups, problems such as overcrowding and confusion in the public spaces of physical examination centers are becoming prominent. This seriously affects the efficiency of medical checkups and the satisfaction of patients. Because of the lack of reference norms and standards, spatial resources are allocated blindly in physical examination centers. Therefore, the reasonable prediction of demands for space and the allocation of areas for public space are problems we need to explore. This study aims to establish a foundation for spatial resource allocation by analyzing the relationship between area allocation and volume of medical checkups and spatial comfort. The objective is to balance service quality and construction costs in physical examination centers. Utilizing AnyLogic, this research simulates pedestrian flow characteristics during peak hours based on empirical data. Additionally, it provides statistics on and analysis of such areas in 30 physical examination centers. The findings reveal that the average per capita allocation of public space ranges from 6.90 to 7.10 m2. The functional relationship between the area of public space (y) and the total area (x) is y = 0.3649x − 57.096. This paper also proposes a relationship between the waiting space and the daily volume of medical checkups according to two comfort levels. The percentages of waiting space in public space ranges from 10% to 12.5% (comfort level) and 7% to 10% (general comfort level). This research provides architects with a specific and operable foundation for space planning, enhancing the standardization and scientification of physical examination center construction. Furthermore, the methodology used in this study proves valuable for future analyses of the interrelationships among functional units in medical buildings. It can also be applied during the postuse evaluation phase, enabling continuous assessment and iterative improvement in the design.
{"title":"Research on Public Space Area Indicators of Physical Examination Centers","authors":"Yuying Dou, Yongquan Chen","doi":"10.3390/buildings14072192","DOIUrl":"https://doi.org/10.3390/buildings14072192","url":null,"abstract":"With the increasing demand for medical checkups, problems such as overcrowding and confusion in the public spaces of physical examination centers are becoming prominent. This seriously affects the efficiency of medical checkups and the satisfaction of patients. Because of the lack of reference norms and standards, spatial resources are allocated blindly in physical examination centers. Therefore, the reasonable prediction of demands for space and the allocation of areas for public space are problems we need to explore. This study aims to establish a foundation for spatial resource allocation by analyzing the relationship between area allocation and volume of medical checkups and spatial comfort. The objective is to balance service quality and construction costs in physical examination centers. Utilizing AnyLogic, this research simulates pedestrian flow characteristics during peak hours based on empirical data. Additionally, it provides statistics on and analysis of such areas in 30 physical examination centers. The findings reveal that the average per capita allocation of public space ranges from 6.90 to 7.10 m2. The functional relationship between the area of public space (y) and the total area (x) is y = 0.3649x − 57.096. This paper also proposes a relationship between the waiting space and the daily volume of medical checkups according to two comfort levels. The percentages of waiting space in public space ranges from 10% to 12.5% (comfort level) and 7% to 10% (general comfort level). This research provides architects with a specific and operable foundation for space planning, enhancing the standardization and scientification of physical examination center construction. Furthermore, the methodology used in this study proves valuable for future analyses of the interrelationships among functional units in medical buildings. It can also be applied during the postuse evaluation phase, enabling continuous assessment and iterative improvement in the design.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"82 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141642921","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072190
Francesco Sommese
Global environmental and health issues such as climate change and the COVID-19 pandemic have highlighted the weaknesses of current urban systems, including the poor availability and accessibility of green and public spaces in cities. Nature-based Solutions are configured as promising solutions to increase the resilience and health of the built environment by addressing climate and pandemic issues, promoting the psycho-physical well-being of users and proposing solutions for the protection of the environment and ecosystems. Following a systematic review of the scientific literature using the PRISMA methodology, this study aims to provide a taxonomic framework for Nature-based Solutions for the built environment that is applicable to the urban and building scales, highlighting key benefits in addressing pandemic and climate challenges and achieving urban resilience. This framework proposes a holistic and multifunctional approach that will prove to be a useful tool for researchers and policy makers to incorporate greening strategies into urban regeneration and redevelopment processes. The application of Nature-based Solutions still seems to be limited. It is therefore necessary to raise awareness of this issue among citizens and policy makers and to promote close co-operation between the different actors in territorial decision-making processes.
{"title":"Nature-Based Solutions to Enhance Urban Resilience in the Climate Change and Post-Pandemic Era: A Taxonomy for the Built Environment","authors":"Francesco Sommese","doi":"10.3390/buildings14072190","DOIUrl":"https://doi.org/10.3390/buildings14072190","url":null,"abstract":"Global environmental and health issues such as climate change and the COVID-19 pandemic have highlighted the weaknesses of current urban systems, including the poor availability and accessibility of green and public spaces in cities. Nature-based Solutions are configured as promising solutions to increase the resilience and health of the built environment by addressing climate and pandemic issues, promoting the psycho-physical well-being of users and proposing solutions for the protection of the environment and ecosystems. Following a systematic review of the scientific literature using the PRISMA methodology, this study aims to provide a taxonomic framework for Nature-based Solutions for the built environment that is applicable to the urban and building scales, highlighting key benefits in addressing pandemic and climate challenges and achieving urban resilience. This framework proposes a holistic and multifunctional approach that will prove to be a useful tool for researchers and policy makers to incorporate greening strategies into urban regeneration and redevelopment processes. The application of Nature-based Solutions still seems to be limited. It is therefore necessary to raise awareness of this issue among citizens and policy makers and to promote close co-operation between the different actors in territorial decision-making processes.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"6 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141642422","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072195
Yingchen Wang, Jiayao Guo, Xiaoxiao Geng, Wei Li
The construction of green buildings is an important direction for the transformation and development of the construction industry, but it is beset with problems such as a lack of construction experience, immature new technologies, and unstable material properties; these issues bring risks to the construction stage of green buildings, and the coupling of uncertain risk factors in the construction process of green buildings may lead to unfavorable results. The purpose of this study is to explore the coupling degree of green building construction safety risk factors and the changing trend in their coupling combinations at the system risk level. First, the risk factor index system was defined by reading the literature and gathering expert opinions, and the coupling degree between risk factors was measured using an improved coupling degree model. Then, a system dynamics model was established to simulate and analyze the coupling effects among the risk factors and determine the combinations with the greatest influence. The results show that the risk probability is proportional to the risk coupling value, the human–environment coupling value is the largest, and the material equipment–management coupling value is the smallest. The human–environment system simulation shows that reducing the coupling value of system factors will promote a decrease in the total level of system risk. According to the research conclusions, measures to prevent risk coupling are proposed, which offer theoretical references for green building practitioners carrying out risk management; these measures hold a certain guiding significance for the risk control and future development of green buildings.
{"title":"Research on Coupling Effect Measurement and Coupling Risk Simulation of Green Building Construction Safety Risk Factors","authors":"Yingchen Wang, Jiayao Guo, Xiaoxiao Geng, Wei Li","doi":"10.3390/buildings14072195","DOIUrl":"https://doi.org/10.3390/buildings14072195","url":null,"abstract":"The construction of green buildings is an important direction for the transformation and development of the construction industry, but it is beset with problems such as a lack of construction experience, immature new technologies, and unstable material properties; these issues bring risks to the construction stage of green buildings, and the coupling of uncertain risk factors in the construction process of green buildings may lead to unfavorable results. The purpose of this study is to explore the coupling degree of green building construction safety risk factors and the changing trend in their coupling combinations at the system risk level. First, the risk factor index system was defined by reading the literature and gathering expert opinions, and the coupling degree between risk factors was measured using an improved coupling degree model. Then, a system dynamics model was established to simulate and analyze the coupling effects among the risk factors and determine the combinations with the greatest influence. The results show that the risk probability is proportional to the risk coupling value, the human–environment coupling value is the largest, and the material equipment–management coupling value is the smallest. The human–environment system simulation shows that reducing the coupling value of system factors will promote a decrease in the total level of system risk. According to the research conclusions, measures to prevent risk coupling are proposed, which offer theoretical references for green building practitioners carrying out risk management; these measures hold a certain guiding significance for the risk control and future development of green buildings.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"13 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141643925","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072186
Shiwei Chen, Zhukai Ye, Weizhuo Lu, Kailun Feng
Concrete is one of the most used building materials globally, leading to a large amount of greenhouse gas (GHG) emissions. Using supplementary cementitious materials (SCM) as replacements for cement in concrete provides an effective way to reduce GHG emissions. However, quantifying the construction performance of using SCM concrete is hard because of complex interactions between concrete’s mechanical properties and construction characteristics, like local energy supply, surrounding temperature and construction plans, which leads to only the fragmental performance of using SCM concrete being explored in previous studies. There still lacks an effective way to quantify the comprehensive performance and provide decision support for contractors about how to use SCM concrete. To deal with the gap, this research proposes a Collection–Simulation–Calculation–Decision (CSCD) method to analyze the complex interactions between concrete and construction, and to quantify the performance of the supply chain–construction when using SCM. A case study is also conducted to demonstrate the effectiveness of the proposed method. The results show that the proposed method is effective in quantifying the performance of using SCM concrete in construction and providing decision support for construction decision makers. A scenario analysis is also conducted to demonstrate the effectiveness of the proposed method in different project characteristics, including the global warming potential (GWP) factors for different construction sites, seasonal temperature changes and different construction plans. The proposed method is an effective tool to quantify the construction performance of using SCM concrete considering complex interactions between concrete mechanical properties and construction characteristics. The results of the research can assist construction decision makers to make decisions about using SCM concrete by comprehensively understanding the impacts shifting along the concrete supply chain and construction.
{"title":"Exploring Performance of Using SCM Concrete: Investigating Impacts Shifting along Concrete Supply Chain and Construction","authors":"Shiwei Chen, Zhukai Ye, Weizhuo Lu, Kailun Feng","doi":"10.3390/buildings14072186","DOIUrl":"https://doi.org/10.3390/buildings14072186","url":null,"abstract":"Concrete is one of the most used building materials globally, leading to a large amount of greenhouse gas (GHG) emissions. Using supplementary cementitious materials (SCM) as replacements for cement in concrete provides an effective way to reduce GHG emissions. However, quantifying the construction performance of using SCM concrete is hard because of complex interactions between concrete’s mechanical properties and construction characteristics, like local energy supply, surrounding temperature and construction plans, which leads to only the fragmental performance of using SCM concrete being explored in previous studies. There still lacks an effective way to quantify the comprehensive performance and provide decision support for contractors about how to use SCM concrete. To deal with the gap, this research proposes a Collection–Simulation–Calculation–Decision (CSCD) method to analyze the complex interactions between concrete and construction, and to quantify the performance of the supply chain–construction when using SCM. A case study is also conducted to demonstrate the effectiveness of the proposed method. The results show that the proposed method is effective in quantifying the performance of using SCM concrete in construction and providing decision support for construction decision makers. A scenario analysis is also conducted to demonstrate the effectiveness of the proposed method in different project characteristics, including the global warming potential (GWP) factors for different construction sites, seasonal temperature changes and different construction plans. The proposed method is an effective tool to quantify the construction performance of using SCM concrete considering complex interactions between concrete mechanical properties and construction characteristics. The results of the research can assist construction decision makers to make decisions about using SCM concrete by comprehensively understanding the impacts shifting along the concrete supply chain and construction.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"44 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141643454","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072187
Meiqin Han, Jianguo Li
This experimental study is carried out in order to improve the properties of sulfate-attacked concrete. The concrete specimens were immersed in 15% Na2SO4 solution before being protected with a concrete repairing agent (CRA). The effects of sulfate corrosion time, the curing time after being attacked, and the concrete repairing agent on concrete were investigated. The experimental results indicate that the properties slightly increased after being attacked by sulfate for 60 days than for 30 days. However, they decreased after being attacked by sulfate for 90 days. CRA could effectively improve the properties of sulfate-attacked concrete. After being re-cured for 7 days, the properties of the sulfate-attacked concrete were significantly improved in comparison with those of the specimens taken out from the sulfate solution immediately. When the specimens were attacked for three months, the compressive strength of specimens coated with CRA was increased by 6.1%, 6.4%, and 6.4% compared to that of the specimens without CRA after being cured for 7 to 56 days, respectively. The carbonation depth of concrete specimens with CRA was reduced by 4.6%, 8.3%, and 4.9%, respectively. However, the chloride ion permeation coefficient of concrete with CRA decreased by 20.3%, 28.5%, and 28.7%, respectively, for the concrete immersed in sulfate for one month.
{"title":"Enhancement of Compressive Strength and Durability of Sulfate-Attacked Concrete","authors":"Meiqin Han, Jianguo Li","doi":"10.3390/buildings14072187","DOIUrl":"https://doi.org/10.3390/buildings14072187","url":null,"abstract":"This experimental study is carried out in order to improve the properties of sulfate-attacked concrete. The concrete specimens were immersed in 15% Na2SO4 solution before being protected with a concrete repairing agent (CRA). The effects of sulfate corrosion time, the curing time after being attacked, and the concrete repairing agent on concrete were investigated. The experimental results indicate that the properties slightly increased after being attacked by sulfate for 60 days than for 30 days. However, they decreased after being attacked by sulfate for 90 days. CRA could effectively improve the properties of sulfate-attacked concrete. After being re-cured for 7 days, the properties of the sulfate-attacked concrete were significantly improved in comparison with those of the specimens taken out from the sulfate solution immediately. When the specimens were attacked for three months, the compressive strength of specimens coated with CRA was increased by 6.1%, 6.4%, and 6.4% compared to that of the specimens without CRA after being cured for 7 to 56 days, respectively. The carbonation depth of concrete specimens with CRA was reduced by 4.6%, 8.3%, and 4.9%, respectively. However, the chloride ion permeation coefficient of concrete with CRA decreased by 20.3%, 28.5%, and 28.7%, respectively, for the concrete immersed in sulfate for one month.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"2 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141642414","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 burgeoning field of sustainable tourism in historically significant urban districts has derived increasing attention in tandem with broader urban economic development. The perceived image of a tourist destination significantly affects tourist consumption behaviors and destination choices, while negative evaluations provide destination managers with insights for targeted improvements to tourist amenities, thereby contributing to the sustainable development of these historically significant districts. This study leveraged Python 3.12.3 software to collect online textual data from popular tourism websites, specifically Ctrip 8.71.4 and Mafengwo 11.1.7. Then, ROST CM6.0 software facilitated high-frequency word analysis, network semantic analysis, and sentiment analysis to outline the perceived image and characteristics of the Macau Historic District, a UNESCO World Heritage site, from the perspective of tourists. The findings are as follows: (1) The image of the Historic Centre of Macao as a tourist destination comprises four primary dimensions: cultural (16.02%), landscape (30.85%), emotional (16.97%), and local (36.16%). (2) Tourists perceive the Historic Centre of Macao as a blend of dynamism and tranquility, tradition, and modernity. (3) Emotional evaluations of the Historic Centre of Macao as a tourist destination are primarily positive (85.45%), whereas negative sentiments constitute 5.76%, with recurring themes pertaining to overcrowding, high prices, a lack of interactive experiences at attractions, excessive commercialization, and insufficient public rest facilities. These findings offer valuable directives for the future planning and development of tourism in Macau, a city recognized for its World Heritage status. (4) In summary, the thematic image of the Historic Centre of Macao can be considered authentic, romantic, and commercialized.
{"title":"Visual Analysis of Social Media Data on Experiences at a World Heritage Tourist Destination: Historic Centre of Macau","authors":"Mengyan Jia, Jingzhao Feng, Yile Chen, Chunxi Zhao","doi":"10.3390/buildings14072188","DOIUrl":"https://doi.org/10.3390/buildings14072188","url":null,"abstract":"The burgeoning field of sustainable tourism in historically significant urban districts has derived increasing attention in tandem with broader urban economic development. The perceived image of a tourist destination significantly affects tourist consumption behaviors and destination choices, while negative evaluations provide destination managers with insights for targeted improvements to tourist amenities, thereby contributing to the sustainable development of these historically significant districts. This study leveraged Python 3.12.3 software to collect online textual data from popular tourism websites, specifically Ctrip 8.71.4 and Mafengwo 11.1.7. Then, ROST CM6.0 software facilitated high-frequency word analysis, network semantic analysis, and sentiment analysis to outline the perceived image and characteristics of the Macau Historic District, a UNESCO World Heritage site, from the perspective of tourists. The findings are as follows: (1) The image of the Historic Centre of Macao as a tourist destination comprises four primary dimensions: cultural (16.02%), landscape (30.85%), emotional (16.97%), and local (36.16%). (2) Tourists perceive the Historic Centre of Macao as a blend of dynamism and tranquility, tradition, and modernity. (3) Emotional evaluations of the Historic Centre of Macao as a tourist destination are primarily positive (85.45%), whereas negative sentiments constitute 5.76%, with recurring themes pertaining to overcrowding, high prices, a lack of interactive experiences at attractions, excessive commercialization, and insufficient public rest facilities. These findings offer valuable directives for the future planning and development of tourism in Macau, a city recognized for its World Heritage status. (4) In summary, the thematic image of the Historic Centre of Macao can be considered authentic, romantic, and commercialized.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"9 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141641985","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072185
Song Xu, Bingtao Xu, Shishui Liulin, Shaoxu Cai, Guangming Tang, Shilong Pan
In this study, compound regeneration of SBS-modified bitumen (SMB) was carried out by a composite rejuvenator composed of furfural extraction oil (FEO) and 1,6-hexanediol diglycidyl ether (HDDGE) in the presence of catalyst triethanolamine (TEOA). SMB was subjected to three aging-regeneration cycles, and the physical and rheological properties, toughness and tenacity, and chemical structures of the SMB after each aging-regeneration cycle were tested to investigate the regeneration effect of the composite rejuvenator on SMB at different numbers of cycles. The ductility decreases and low-temperature properties deteriorate as the number of cycles increased, but the high-temperature properties of the SMB are improved. The complex modulus aging index and phase angle aging index indicate that the viscous behavior of SMB weakens after the second and third aging. The degree of viscoelasticity and toughness recovery decreases with the increase in the number of cycles, and the tenacity of SMB after the third aging-regeneration cycle is basically lost. The results of the Fourier transform infrared (FTIR) spectra tests prove that with the increase in the aging–regeneration cycles of SMB, the intensity of FTIR peaks of oxygen-containing functional groups is greater, and the recovery of aged SMB is gradually weakened.
{"title":"Performance Evaluation of Multiple Aging-Regeneration of SBS-Modified Bitumen Regenerated by a Composite Rejuvenator","authors":"Song Xu, Bingtao Xu, Shishui Liulin, Shaoxu Cai, Guangming Tang, Shilong Pan","doi":"10.3390/buildings14072185","DOIUrl":"https://doi.org/10.3390/buildings14072185","url":null,"abstract":"In this study, compound regeneration of SBS-modified bitumen (SMB) was carried out by a composite rejuvenator composed of furfural extraction oil (FEO) and 1,6-hexanediol diglycidyl ether (HDDGE) in the presence of catalyst triethanolamine (TEOA). SMB was subjected to three aging-regeneration cycles, and the physical and rheological properties, toughness and tenacity, and chemical structures of the SMB after each aging-regeneration cycle were tested to investigate the regeneration effect of the composite rejuvenator on SMB at different numbers of cycles. The ductility decreases and low-temperature properties deteriorate as the number of cycles increased, but the high-temperature properties of the SMB are improved. The complex modulus aging index and phase angle aging index indicate that the viscous behavior of SMB weakens after the second and third aging. The degree of viscoelasticity and toughness recovery decreases with the increase in the number of cycles, and the tenacity of SMB after the third aging-regeneration cycle is basically lost. The results of the Fourier transform infrared (FTIR) spectra tests prove that with the increase in the aging–regeneration cycles of SMB, the intensity of FTIR peaks of oxygen-containing functional groups is greater, and the recovery of aged SMB is gradually weakened.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"10 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141640703","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072189
Wenbo Cheng, Wei Yin, Xiaoya Wang, Quan Xu, Guodong Wang, Jun Cao, Shengxue Zhu
In order to study the effects of soda residue content, particle size, moisture content, and curing age on the unconfined compressive strength (UCS) of soda residue cement lime soil (SRCLS), a 4-factor, 4-level orthogonal experimental design was employed in this study. Different conditions of SRCLS UCS and their impacts were tested and analyzed. The internal microstructure and hydration products of SRCLS were studied using SEM and XRD to explore the strengthening mechanism of SR in SRCLS. The results indicate that as the soda residue content gradually increased, SRCLS UCS initially increased and then decreased, with a maximum increase of up to 67%. With increasing soda residue particle size and moisture content, the UCS of SRCLS gradually decreased. The optimized mix ratio was determined to be soda residue:cement:lime:soil = 3%:3%:6%:100%, with the soda residue dried naturally and an ideal particle size of 0.15 mm. The factors influencing the unconfined compressive strength (UCS) of SRCLS, in order of importance, are curing age, soda residue content, moisture content, and particle size of SR. Among these, curing age and soda residue content have a significant impact on the UCS. An adequate amount of SR can act as a fine aggregate filler, replace lime, promote cement hydration, and enhance chloride ion binding. This improves the grading of SRCLS materials and facilitates the formation of cementitious products from AFm, AFt, and Friedel’s salt, resulting in denser and stronger SRCLS materials. The research findings provide a reference for the mix design of SRCLS and the large-scale utilization of waste soda residue.
{"title":"Multi-Factor Orthogonal Experiments and Enhancement Mechanisms of Unconfined Compressive Strength of Soda Residue Cement Lime Soil","authors":"Wenbo Cheng, Wei Yin, Xiaoya Wang, Quan Xu, Guodong Wang, Jun Cao, Shengxue Zhu","doi":"10.3390/buildings14072189","DOIUrl":"https://doi.org/10.3390/buildings14072189","url":null,"abstract":"In order to study the effects of soda residue content, particle size, moisture content, and curing age on the unconfined compressive strength (UCS) of soda residue cement lime soil (SRCLS), a 4-factor, 4-level orthogonal experimental design was employed in this study. Different conditions of SRCLS UCS and their impacts were tested and analyzed. The internal microstructure and hydration products of SRCLS were studied using SEM and XRD to explore the strengthening mechanism of SR in SRCLS. The results indicate that as the soda residue content gradually increased, SRCLS UCS initially increased and then decreased, with a maximum increase of up to 67%. With increasing soda residue particle size and moisture content, the UCS of SRCLS gradually decreased. The optimized mix ratio was determined to be soda residue:cement:lime:soil = 3%:3%:6%:100%, with the soda residue dried naturally and an ideal particle size of 0.15 mm. The factors influencing the unconfined compressive strength (UCS) of SRCLS, in order of importance, are curing age, soda residue content, moisture content, and particle size of SR. Among these, curing age and soda residue content have a significant impact on the UCS. An adequate amount of SR can act as a fine aggregate filler, replace lime, promote cement hydration, and enhance chloride ion binding. This improves the grading of SRCLS materials and facilitates the formation of cementitious products from AFm, AFt, and Friedel’s salt, resulting in denser and stronger SRCLS materials. The research findings provide a reference for the mix design of SRCLS and the large-scale utilization of waste soda residue.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"8 25","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141640426","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072193
Nastja Podrekar Loredan, Eva Prelovšek Niemelä, N. Šarabon
Studies indicate that natural wooden materials positively affect students’ well-being in classrooms. In addition, students spend a considerable amount of their time in classrooms predominantly seated, making school interiors a suitable place to reduce sedentary behaviors of children. A mixed team of experts in human factors, architecture, design and engineering designed a prototype wooden standing desk for indoor use and formed focus groups with students and teachers to gather feedback on the development process and to evaluate the suitability of the prototype. The prototype desk was well received by the primary school teachers and students. The students appreciated plywood as the main material for the construction of the desk; however, they criticized that the wooden tabletop should be more resistant. The height adjustability of the desk and the tiltable tabletop were the most appreciated features of the prototype. Further studies should be conducted to investigate the optimal material, shape and color of the school desk, especially the tabletop, and additional efforts should be made to design furniture that promotes a less sedentary classroom and improves students’ well-being at school.
{"title":"Classroom Interior Design: Wooden Furniture Prototype with Feedback from Students and Teachers","authors":"Nastja Podrekar Loredan, Eva Prelovšek Niemelä, N. Šarabon","doi":"10.3390/buildings14072193","DOIUrl":"https://doi.org/10.3390/buildings14072193","url":null,"abstract":"Studies indicate that natural wooden materials positively affect students’ well-being in classrooms. In addition, students spend a considerable amount of their time in classrooms predominantly seated, making school interiors a suitable place to reduce sedentary behaviors of children. A mixed team of experts in human factors, architecture, design and engineering designed a prototype wooden standing desk for indoor use and formed focus groups with students and teachers to gather feedback on the development process and to evaluate the suitability of the prototype. The prototype desk was well received by the primary school teachers and students. The students appreciated plywood as the main material for the construction of the desk; however, they criticized that the wooden tabletop should be more resistant. The height adjustability of the desk and the tiltable tabletop were the most appreciated features of the prototype. Further studies should be conducted to investigate the optimal material, shape and color of the school desk, especially the tabletop, and additional efforts should be made to design furniture that promotes a less sedentary classroom and improves students’ well-being at school.","PeriodicalId":505657,"journal":{"name":"Buildings","volume":"6 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141640877","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}
Pub Date : 2024-07-16DOI: 10.3390/buildings14072191
Jingjing He, Chuanwu Sun, Xuezhi Wang
When using seawater and sea sand as mixes, the mechanical properties and durability of concrete are adversely affected because the raw materials themselves contain harmful ions. Fly ash is the tailings formed in the process of industrial production, the use of which does not require the burning of clinker, reducing CO2 emissions. Moreover, it belongs to a new type of cementitious materials with low emissions and high environmental protection. Fly ash enhances the properties of concrete and reduces the effect of harmful ions on concrete. Based on the above considerations, the corresponding specimens were prepared and subjected to cubic compressive strength, flexural strength, and seawater freezing and thawing resistance tests by using fly ash admixture as the main variable. A combination of macro-analysis and micro-analysis was used to investigate the effect of fly ash on the performance of seawater sea sand concrete. The results showed that fly ash significantly enhanced the mechanical properties and resistance to seawater freezing and thawing of seawater sea sand concrete. The best improvement in compressive strength and resistance to seawater freezing and thawing was achieved at a substitution rate of 20%. The maximum increase in compressive strength was 13.22%. The maximum reduction in mass loss rate was 57.26% and the strength loss rate was 43.14% after the specimens were subjected to seawater freezing and thawing 75 times. The maximum enhancement in flexural strength was 17.06% for a substitution rate of 10%. Through microanalysis, it can be seen that the incorporation of coal ash can enhance the compactness of concrete through the microaggregate effect as well as the volcanic ash reaction to promote the secondary hydration reaction, so as to strengthen the seawater freeze–thaw resistance of seawater sea sand concrete. Finally, the damage prediction model established using the mean GM (1, 1) model of gray system theory meets the requirements of the first level of prediction accuracy and can accurately predict the damage of seawater sea sand concrete under seawater freezing and thawing.
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