1 Introduction Xingfa Cement Plant,which is located in Beijing's Huairou District,operated as a limestone quarry for 23 years,causing substantial ecological degradation.The site,encompassing 41.67 hm²within t...1 Introduction Xingfa Cement Plant,which is located in Beijing's Huairou District,operated as a limestone quarry for 23 years,causing substantial ecological degradation.The site,encompassing 41.67 hm²within the cultural heritage buffer zone of the Great Wall,was left with a barren scar in the landscape.Following the shutdown of the plant in 2015 under Beijing's Clean Air Initiative,the site became adjacent to a growing cluster of national science and technology parks,universities,residential communities,and tourist destinations.In response to these shifts,the project seeks to rehabilitate the site,transforming it into a national research campus and a rural park.展开更多
The demand for alternative cementitious materials is on the rise,as the cement causes huge energy consumption and produces greenhouse gas emission.Additionally,there is economic potential for the construction industry...The demand for alternative cementitious materials is on the rise,as the cement causes huge energy consumption and produces greenhouse gas emission.Additionally,there is economic potential for the construction industry to reuse wastes as supplementary building materials.The purpose of this study is to evaluate the potential of utilizing ferrochrome slag wastes in mortar as supplementary cementitious materials (SCMs),thereby achieving this double-sided goal.Thus,the mechanical and physical properties of ferrochrome slag wastes were investigated to be used as admixtures in concrete production.Three different cement mortar specimens were prepared by replacing cement with ferrochrome slag in ratios of 0,30%,and 60% by mass and flexural and compressive strengths of the specimens were determined at the ages of 7,28,56,90,and 180 days.Also,the effects of the ferrochrome slag replacement ratio on workability,setting time and volume expansion were revealed.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were also investigated to study the microstructural properties of the specimens containing ferrochrome slag.Based on the results,it is concluded that ferrochrome slag wastes have pozzolanic activity,therefore reusing them as SCMs in the cement and concrete industry is convenient.展开更多
The science space in a state school in Natal city was built using a composite consisting of gypsum, EPS （expanded polystyrene）, shredded tire, cement and water. Mechanical and thermal resistances were evaluated. Ins...The science space in a state school in Natal city was built using a composite consisting of gypsum, EPS （expanded polystyrene）, shredded tire, cement and water. Mechanical and thermal resistances were evaluated. Inside the blocks, three types of fillings （EPS plates, aluminum cans and 500 mL bottles of mineral water） were placed in order to obtain a walls with higher thermal resistance, but also to give it an ecologically correct order, considering that both the tire and the EPS occupy a large space in landfills and require years to be degraded when released into the environment. Compression tests were conducted according to the rules. The experiments demonstrated that the temperature difference between the internal and external surfaces on the walls reached levels above 12.0 ℃. It was also demonstrated that the proposed composite has adequate mechanical strength to be used for sealing walls. The proposed use of the composite can contribute to reduce the significant housing deficit of Brazil, producing popular houses at low cost and with little time to work.展开更多
Deconstruction is the selective dismantling of building structures to recover the maximum amount of primarily reusable and secondarily recyclable materials in a safe and cost-effective manner.Deconstruction is a labor...Deconstruction is the selective dismantling of building structures to recover the maximum amount of primarily reusable and secondarily recyclable materials in a safe and cost-effective manner.Deconstruction is a labor intensive process and can be difficult to achieve in a time-efficient and economical manner for light wood-framed buildings.Deconstruction techniques that balance hand and mechanical labor must be developed to maintain the integrity of materials for reuse and obtain maximum salvage value per unit of cost and time-on-site.This project entailed the removal of three identical WWII-era two-story wood-framed barracks buildings at Ft.McClellan Army Base,Anniston,AL,using hand deconstruction,combined mechanical and hand deconstruction techniques,and a traditional demolition method,i.e.,mechanical reduction and disposal,in order to determine“optimal”deconstruction techniques based on salvage value per unit of cost.The maximum practical materials salvage from the study buildings using 100%hand deconstruction techniques was 39%of the mass by weight.A combination of hand and mechanical techniques was discovered to have approximately the same economic efficiency as 100%hand deconstruction,measured as a ratio of gross cost per salvage value,with a 44.6%reduction in total labor-hours,and a reduction of only 7%of salvage materials by weight.These findings indicate the potential for greatly increasing wood-framed building deconstruction practice relative to the additional time-on-site and labor that is required,compared to demolition,while optimizing economic benefits.This paper describes the research methods and deconstruction techniques employed,and lessons learned to advance the practice of deconstruction to be more economically competitive and time-efficient.展开更多
文摘1 Introduction Xingfa Cement Plant,which is located in Beijing's Huairou District,operated as a limestone quarry for 23 years,causing substantial ecological degradation.The site,encompassing 41.67 hm²within the cultural heritage buffer zone of the Great Wall,was left with a barren scar in the landscape.Following the shutdown of the plant in 2015 under Beijing's Clean Air Initiative,the site became adjacent to a growing cluster of national science and technology parks,universities,residential communities,and tourist destinations.In response to these shifts,the project seeks to rehabilitate the site,transforming it into a national research campus and a rural park.
文摘The demand for alternative cementitious materials is on the rise,as the cement causes huge energy consumption and produces greenhouse gas emission.Additionally,there is economic potential for the construction industry to reuse wastes as supplementary building materials.The purpose of this study is to evaluate the potential of utilizing ferrochrome slag wastes in mortar as supplementary cementitious materials (SCMs),thereby achieving this double-sided goal.Thus,the mechanical and physical properties of ferrochrome slag wastes were investigated to be used as admixtures in concrete production.Three different cement mortar specimens were prepared by replacing cement with ferrochrome slag in ratios of 0,30%,and 60% by mass and flexural and compressive strengths of the specimens were determined at the ages of 7,28,56,90,and 180 days.Also,the effects of the ferrochrome slag replacement ratio on workability,setting time and volume expansion were revealed.Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were also investigated to study the microstructural properties of the specimens containing ferrochrome slag.Based on the results,it is concluded that ferrochrome slag wastes have pozzolanic activity,therefore reusing them as SCMs in the cement and concrete industry is convenient.
文摘The science space in a state school in Natal city was built using a composite consisting of gypsum, EPS （expanded polystyrene）, shredded tire, cement and water. Mechanical and thermal resistances were evaluated. Inside the blocks, three types of fillings （EPS plates, aluminum cans and 500 mL bottles of mineral water） were placed in order to obtain a walls with higher thermal resistance, but also to give it an ecologically correct order, considering that both the tire and the EPS occupy a large space in landfills and require years to be degraded when released into the environment. Compression tests were conducted according to the rules. The experiments demonstrated that the temperature difference between the internal and external surfaces on the walls reached levels above 12.0 ℃. It was also demonstrated that the proposed composite has adequate mechanical strength to be used for sealing walls. The proposed use of the composite can contribute to reduce the significant housing deficit of Brazil, producing popular houses at low cost and with little time to work.
文摘Deconstruction is the selective dismantling of building structures to recover the maximum amount of primarily reusable and secondarily recyclable materials in a safe and cost-effective manner.Deconstruction is a labor intensive process and can be difficult to achieve in a time-efficient and economical manner for light wood-framed buildings.Deconstruction techniques that balance hand and mechanical labor must be developed to maintain the integrity of materials for reuse and obtain maximum salvage value per unit of cost and time-on-site.This project entailed the removal of three identical WWII-era two-story wood-framed barracks buildings at Ft.McClellan Army Base,Anniston,AL,using hand deconstruction,combined mechanical and hand deconstruction techniques,and a traditional demolition method,i.e.,mechanical reduction and disposal,in order to determine“optimal”deconstruction techniques based on salvage value per unit of cost.The maximum practical materials salvage from the study buildings using 100%hand deconstruction techniques was 39%of the mass by weight.A combination of hand and mechanical techniques was discovered to have approximately the same economic efficiency as 100%hand deconstruction,measured as a ratio of gross cost per salvage value,with a 44.6%reduction in total labor-hours,and a reduction of only 7%of salvage materials by weight.These findings indicate the potential for greatly increasing wood-framed building deconstruction practice relative to the additional time-on-site and labor that is required,compared to demolition,while optimizing economic benefits.This paper describes the research methods and deconstruction techniques employed,and lessons learned to advance the practice of deconstruction to be more economically competitive and time-efficient.
