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1.
Sci Total Environ ; 750: 141518, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32871367

RESUMO

In order to promote the development of the biogas industry, solutions are needed to improve concrete structures durability in this environment. This multiphysics study aims to analyse the multiphases interactions between the liquid phase of an anaerobic digestion system and cementitious matrices, focusing on (i) the impacts of the binder nature on the anaerobic digestion process at local scale, and (ii) the deterioration mechanisms of the materials. Cementitious pastes made of slag cement (CEM III), innovative metakaolin-based alkali-activated material (MKAA), with compositions presumed to resist chemically aggressive media, and a reference binder, ordinary Portland cement (CEM I), were tested by immersion in inoculated cattle manure in bioreactors for a long period of five digestion cycles. For the first time it was shown that the digestion process was disturbed in the short term by the presence of the materials that increased the pH of the liquid phase and slowed the acids consumption, with much more impact of the MKAA. However, the final total production of biogas was similar in all bioreactors. Material analyses showed that, in this moderately aggressive medium, the biodeterioration of the CEM I and CEM III pastes mainly led to cement matrix leaching (decalcification) and carbonation. MKAA showed a good behaviour with very low degraded depths. In addition, the material was found to have interesting ammonium adsorption properties in the chemical conditions (notably the pH range) of anaerobic digestion.


Assuntos
Reatores Biológicos , Materiais de Construção , Álcalis , Anaerobiose , Animais , Biocombustíveis , Bovinos
2.
Sci Data ; 7(1): 392, 2020 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-33168822

RESUMO

We constructed a near-real-time daily CO2 emission dataset, the Carbon Monitor, to monitor the variations in CO2 emissions from fossil fuel combustion and cement production since January 1, 2019, at the national level, with near-global coverage on a daily basis and the potential to be frequently updated. Daily CO2 emissions are estimated from a diverse range of activity data, including the hourly to daily electrical power generation data of 31 countries, monthly production data and production indices of industry processes of 62 countries/regions, and daily mobility data and mobility indices for the ground transportation of 416 cities worldwide. Individual flight location data and monthly data were utilized for aviation and maritime transportation sector estimates. In addition, monthly fuel consumption data corrected for the daily air temperature of 206 countries were used to estimate the emissions from commercial and residential buildings. This Carbon Monitor dataset manifests the dynamic nature of CO2 emissions through daily, weekly and seasonal variations as influenced by workdays and holidays, as well as by the unfolding impacts of the COVID-19 pandemic. The Carbon Monitor near-real-time CO2 emission dataset shows a 8.8% decline in CO2 emissions globally from January 1st to June 30th in 2020 when compared with the same period in 2019 and detects a regrowth of CO2 emissions by late April, which is mainly attributed to the recovery of economic activities in China and a partial easing of lockdowns in other countries. This daily updated CO2 emission dataset could offer a range of opportunities for related scientific research and policy making.


Assuntos
Dióxido de Carbono/análise , Materiais de Construção/análise , Monitoramento Ambiental , Emissões de Veículos/análise , Infecções por Coronavirus , Pandemias , Pneumonia Viral
3.
Mar Environ Res ; 161: 105081, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33070934

RESUMO

Concrete is used in marine coastal constructions worldwide. These structures are colonized by specialized hard-bottom biota consisting of macroalgae and benthic macrofauna. As concrete manufacturers face challenges such as limited natural resources and high CO2-emissions, the need for supplementary materials increases. Still, there has been little research on the reaction of species to the differences in concrete composition and what ecological impact these reactions could have. This study addresses the questions (1) if there are differences in settlement communities, depending on differences in concrete constitutes and (2) if so, what are the consequences for the usability of alternative concretes in marine constructions. For the experiment 15 cubes (15 × 15 × 15 cm) made of five different concretes, containing different cements (Portland cement and blast furnace cements) and aggregates (sand, gravel, iron ore and metallurgical slags) were deployed in a natural hard bottom experimental field near Helgoland Island (German Bight) in April 2016. After 12 months, all cubes were examined regarding species composition and coverage, followed by statistical analysis (PERMANOVA, SIMPER, DIVERSE). Results indicate differences in settlement communities for different surface orientation (Top, Front/Back) of the cubes. Significant differences in settlement communities of the Front/Back side were present depending on the used material type. However, the found differences in settlement between the concrete types tested are not sufficiently clear to provide recommendations for their usability in coastal constructions.


Assuntos
Biota , Materiais de Construção
4.
PLoS One ; 15(10): e0237264, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002034

RESUMO

The precise evaluation of the potential damage caused by large commercial aircraft crash into civil structures, especially nuclear power plants (NPPs), has become essential design consideration. In this study, impact of Boeing 767 against rigid wall and outer containment building (reinforced concrete) of an NPP are simulated in ANSYS/LS-DYNA by using both force time history and missile target interaction methods with impact velocities ranging from 100 m/s to 150 m/s. The results show that impact loads, displacements, stresses for concrete and steel reinforcement, and damaged elements are higher in case of force time history method than missile target interaction method, making the former relatively conservative. It is observed that no perforation or scabbing takes place in case of 100 m/s impact speed, thus preventing any potential leakage. With full mass of Boeing 767 and impact velocity slightly above 100 m/s, the outer containment building can prevent local failure modes. At impact velocity higher than 120 m/s, scabbing and perforations are dominant. This concludes that in design and assessment of NPP structures against aircraft loadings, sufficient thickness or consideration of steel plates are essential to account for local failure modes and overall structural integrity. Furthermore, validation and application of detail 3D finite element and material models to full-scale impact analysis have been carried out to expand the existing database. In rigid wall impact analysis, the impact forces and impulses from FE analysis and Riera's method correspond well, which satisfies the recommendations of relevant standards and further ensure the accuracy of results in full-scale impact analysis. The methodology presented in this paper is extremely effective in simulating structural evaluation of full-scale aircraft impact on important facilities such as NPPs.


Assuntos
Acidentes Aeronáuticos , Aeronaves , Liberação Nociva de Radioativos , Acidentes Aeronáuticos/estatística & dados numéricos , Códigos de Obras , Simulação por Computador , Materiais de Construção/estatística & dados numéricos , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional , Fenômenos Mecânicos , Modelos Teóricos , Centrais Nucleares , Fenômenos Físicos , Liberação Nociva de Radioativos/prevenção & controle , Liberação Nociva de Radioativos/estatística & dados numéricos , Aço , Colapso Estrutural/prevenção & controle , Colapso Estrutural/estatística & dados numéricos
5.
Cochrane Database Syst Rev ; 10: CD013398, 2020 10 15.
Artigo em Inglês | MEDLINE | ID: mdl-33058136

RESUMO

BACKGROUND: Despite being preventable, malaria remains an important public health problem. The World Health Organization (WHO) reports that overall progress in malaria control has plateaued for the first time since the turn of the century. Researchers and policymakers are therefore exploring alternative and supplementary malaria vector control tools. Research in 1900 indicated that modification of houses may be effective in reducing malaria: this is now being revisited, with new research now examining blocking house mosquito entry points or modifying house construction materials to reduce exposure of inhabitants to infectious bites. OBJECTIVES: To assess the effects of house modifications on malaria disease and transmission. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register; Central Register of Controlled Trials (CENTRAL), published in the Cochrane Library; MEDLINE (PubMed); Embase (OVID); Centre for Agriculture and Bioscience International (CAB) Abstracts (Web of Science); and the Latin American and Caribbean Health Science Information database (LILACS), up to 1 November 2019. We also searched the WHO International Clinical Trials Registry Platform (www.who.int/ictrp/search/en/), ClinicalTrials.gov (www.clinicaltrials.gov), and the ISRCTN registry (www.isrctn.com/) to identify ongoing trials up to the same date. SELECTION CRITERIA: Randomized controlled trials, including cluster-randomized controlled trials (cRCTs), cross-over studies, and stepped-wedge designs were eligible, as were quasi-experimental trials, including controlled before-and-after studies, controlled interrupted time series, and non-randomized cross-over studies. We only considered studies reporting epidemiological outcomes (malaria case incidence, malaria infection incidence or parasite prevalence). We also summarised qualitative studies conducted alongside included studies. DATA COLLECTION AND ANALYSIS: Two review authors selected eligible studies, extracted data, and assessed the risk of bias. We used risk ratios (RR) to compare the effect of the intervention with the control for dichotomous data. For continuous data, we presented the mean difference; and for count and rate data, we used rate ratios. We presented all results with 95% confidence intervals (CIs). We assessed the certainty of evidence using the GRADE approach. MAIN RESULTS: Six cRCTs met our inclusion criteria, all conducted in sub-Saharan Africa; three randomized by household, two by village, and one at the community level. All trials assessed screening of windows, doors, eaves, ceilings or any combination of these; this was either alone, or in combination with eave closure, roof modification or eave tube installation (a "lure and kill" device that reduces mosquito entry whilst maintaining some airflow). In two trials, the interventions were insecticide-based. In five trials, the researchers implemented the interventions. The community implemented the interventions in the sixth trial. At the time of writing the review, two of the six trials had published results, both of which compared screened houses (without insecticide) to unscreened houses. One trial in Ethiopia assessed screening of windows and doors. Another trial in the Gambia assessed full screening (screening of eaves, doors and windows), as well as screening of ceilings only. Screening may reduce clinical malaria incidence caused by Plasmodium falciparum (rate ratio 0.38, 95% CI 0.18 to 0.82; 1 trial, 184 participants, 219.3 person-years; low-certainty evidence; Ethiopian study). For malaria parasite prevalence, the point estimate, derived from The Gambia study, was smaller (RR 0.84, 95% CI 0.60 to 1.17; 713 participants, 1 trial; moderate-certainty evidence), and showed an effect on anaemia (RR 0.61, 95% CI 0.42, 0.89; 705 participants; 1 trial, moderate-certainty evidence). Screening may reduce the entomological inoculation rate (EIR): both trials showed lower estimates in the intervention arm. In the Gambian trial, there was a mean difference in EIR between the control houses and treatment houses ranging from 0.45 to 1.50 (CIs ranged from -0.46 to 2.41; low-certainty evidence), depending on the study year and treatment arm. The Ethiopian trial reported a mean difference in EIR of 4.57, favouring screening (95% CI 3.81 to 5.33; low-certainty evidence). Pooled analysis of the trials showed that individuals living in fully screened houses were slightly less likely to sleep under a bed net (RR 0.84, 95% CI 0.65 to 1.09; 2 trials, 203 participants). In one trial, bed net usage was also lower in individuals living in houses with screened ceilings (RR 0.69, 95% CI 0.50 to 0.95; 1 trial, 135 participants). AUTHORS' CONCLUSIONS: Based on the two trials published to date, there is some evidence that screening may reduce malaria transmission and malaria infection in people living in the house. The four trials awaiting publication are likely to enrich the current evidence base, and we will add these to this review when they become available.


Assuntos
Materiais de Construção , Habitação , Malária Falciparum/prevenção & controle , Adolescente , Adulto , África ao Sul do Saara , Anemia/diagnóstico , Anemia/epidemiologia , Animais , Arquitetura , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Inseticidas , Malária Falciparum/epidemiologia , Masculino , Mosquitos Vetores , Plasmodium falciparum , Gravidez , Prevalência , Ensaios Clínicos Controlados Aleatórios como Assunto
6.
Waste Manag ; 118: 610-625, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33010692

RESUMO

China produced a large amount of construction and demolition (C&D) waste, owing to the rapid development of construction industry. Although a set of policies and regulations are being drafted in China for promoting C&D waste recycling, execution of these policies in practice seems to be far from effective. Currently, approximately 75% of Chinese cities are still surrounded by large volumes of C&D waste. Therefore, identification of challenges in the development of C&D waste management, specially recycling, is essential. This paper employs site visits to 10 recycling plants in 10 Chinese cities (Shanghai, Hangzhou, Suzhou, Chongqing, Chengdu, Xi'an, Changsha, Shenzhen, Nanjing, and Zhoukou) and interviews with 25 industry practitioners for examining the challenges. Eight challenges are identified: (1) unstable source of C&D waste for recycling, (2) absence of subsidies for recycling activities and high cost for land use, (3) insufficient attention paid to design for waste minimisation, (4) absence of regulations on on-site sorting, (5) unregulated landfill activities, (6) a lack of coordination among different government administration departments, (7) a lack of accurate estimation of waste quantity and distribution, and (8) a lack of an effective waste tracing system. Recommendations to address these challenges are presented. The results of this study are expected to aid policy makers in formulation of proper C&D waste management in China and provide a useful reference for researchers who are interested in C&D waste recycling industry.


Assuntos
Materiais de Construção , Gerenciamento de Resíduos , China , Cidades , Reciclagem
7.
Artigo em Inglês | MEDLINE | ID: mdl-32872529

RESUMO

The low efficiency of the closed-loop supply chain in construction and demolition waste (CDW) recycling has restricted the green development of China's construction industry. Additionally, the government's reward-penalty mechanism has a huge influence on green development. This study aimed to investigate the effect of green development performance (GDP) and the government's reward-penalty mechanism on the decision-making process of production and recycling units, as well as to reveal the optimal strategies under different conditions. Therefore, the strategies' evolutionary paths of production and recycling units were investigated by using evolutionary game theory. Firstly, an evolutionary game model between production units and recycling units was proposed under the government's reward-penalty mechanism. Then, the evolutionary stability strategies in different scenarios were discussed. Finally, the effects of the relevant parameters on the evolutionary paths of the game model were analyzed using numerical simulations. The main conclusions are as follows. (1) When the range of GDP changes, the evolutionary stable strategy changes accordingly. GDP plays a positive role in promoting the high-quality development of the CDW recycling supply chain, but an increase in GDP can easily lead to the simultaneous motivation of free-riding. (2) The government's reward-penalty mechanism effectively regulates the decision-making process of production and recycling units. An increase in the subsidy rate and supervision probability helps to reduce free-riding behavior. Moreover, the incentive effect of the subsidy probability on recycling units is more obvious, while the effect of the supervision probability on improving the motivation of active participation for production units is more remarkable. This paper not only provides a decision-making basis to ensure production and recycling units to make optimal strategy choices under different conditions but also provides a reference for the government to formulate a reasonable reward-penalty mechanism that is conducive to a macro-control market.


Assuntos
Indústria da Construção , Teoria do Jogo , Gerenciamento de Resíduos , China , Materiais de Construção , Governo , Humanos , Reciclagem , Recompensa , Desenvolvimento Sustentável
8.
J Environ Manage ; 276: 111124, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32871463

RESUMO

The tailings and rice straw that are produced in large quantities each year in the mining and agricultural industries, respectively, have significant effects on the ecological environment. This study aimed to explore the mechanical properties of cemented tailings backfill (CTB) mixed with alkalized rice straw (ARS) of different lengths. A series of uniaxial compressive strength (UCS) and indirect tensile strength (ITS) tests were conducted on the CTB. The results indicated that as the length of the ARS increased from 3 to 15 mm, the UCS and ITS values initially increased and then decreased. The critical length of the ARS was 12 mm, for which the effect of strength increase was the most significant. From the overall analysis, the UCS of CTB samples with ARS (9 and 12 mm) demonstrated the better improvement (increased by 10.0 and 14.7%, respectively) at 28 d curing age, and the improvement effect of the CTB samples with ARS of other lengths was not ideal. The ITS of CTB samples with ARS increased (except for an ARS length of 3 mm) regardless of the curing age; the maximum increase was approximately 24.2% at 28 d. The integrity, residual strength, and toughness of CTB sample with the ARS (12 mm) were the largest after the UCS test. Scanning electron microscopy (SEM) tests indicated that the surface of the ARS was covered with cement hydration products, and the interior of the ARS was filled with cement tailings, which produced stronger adhesion between the ARS (12 mm) and CTB matrix; the ARS performed a bridging role and suppressed crack propagation, which effectively improving the mechanical properties of CTB. Significantly short ARS exhibited a lower adhesive force with the matrix, and significantly long ARS exhibited a lower filling rate. Thus, while improving the mechanical properties of CTB, ARS provides a new method for treating rice straw and decreasing its combustion pollution.


Assuntos
Oryza , Força Compressiva , Materiais de Construção , Poluição Ambiental , Mineração
9.
J Environ Manage ; 276: 111274, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32911386

RESUMO

Effect of triisopropanolamine (TIPA) on compressive strength and hydration properties of cement-lithium slag (LS, 30%) paste was studied. The results demonstrated that the addition of TIPA is advantageous for compressive strength at 7 d, 28 d and 60 d. The reason was related to the pore complexity and hydration process of cement and LS. TIPA reduced the total porosity, and increased the fractal dimension, making the pore structure more complicated. In addition, TIPA promoted the pozzolanic reaction of LS and the hydration of cement, expediting the formation of C-S(A)-H gel. TIPA accelerated the dissolution of aluminate ions, silicate ions and ferric ions in the pore solution, thereby accelerating the pozzolanic reaction of LS. During the hydration of cement-LS paste, TIPA facilitated the conversion of ettringite to the AFm-like phase and produced more C-A-S-H gel by promoting the dissolution of aluminate ions.


Assuntos
Lítio , Propanolaminas , Materiais de Construção , Silicatos
10.
PLoS One ; 15(9): e0238505, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32915839

RESUMO

Previous research has indicated that many European buildings are vulnerable to moderate-magnitude earthquakes. For example, during the L´Aquila (Italia, Mw 6.3, 2009) and Lorca (Spain, Mw 5.9, 2011) earthquakes, many old buildings were severely damaged and some of them collapsed. In specific, significant damage has been found in several school buildings after past earthquakes in Europe. This is due to the fact that many of them were constructed prior to the current seismic codes, thus considering only gravitational loads and with no seismic design whatsoever. Primary schools are even more vulnerable than other typologies because of their low adult/child ratio. The seismic activity of the Iberian Peninsula is low-moderate. However, the Algarve and Huelva regions, which are situated in the south-west, are influenced by large faults which have caused major earthquakes of long-return periods. The European project PERSISTAH (Projetos de Escolas Resilientes aos SISmos no Território do Algarve e de Huelva, in Portuguese) aims to cooperatively evaluate the seismic vulnerability of primary schools in the Algarve (Portugal) and Huelva (Spain) regions. The present work is framed under this project. The objective of this paper is to determine the most effective retrofitting scheme for a typical primary school building in this area, considering structural, architectural and constructive parameters. The scheme could be applied to several buildings of the same typology, decreasing costs and time. An existing reinforced concrete frame building has been selected for the study. This is one of the most commonly used typologies for primary schools in this area. A nonlinear static analysis has been carried out in order to study its seismic behaviour. The performance point of the building has been obtained through the capacity-demand spectrum method. The preliminary results have confirmed the poor seismic behaviour of this building. Specifically, soft-story behaviour has been identified in the ground floor and short columns have been observed in the upper floors. Therefore, specific seismic retrofitting solutions have been proposed and evaluated in order to identify the one that is the most efficient. The combination of reinforcements has been done considering the structural and architectural impact and constructive parameters. The calculations have shown that steel X-bracings are the best solution for preventing the formation of a soft-storey in the ground floor. Unfortunately, this scheme increases the deformation in the upper floor columns. The best solution for the upper floors' short columns has been the use of steel jackets. The results have also shown that this combination produces an important reduction of the expected general damage level. The resulting retrofitting scheme can be extrapolated to other buildings with a similar typology.


Assuntos
Materiais de Construção , Terremotos , Instituições Acadêmicas , Aço , Itália , Modelos Teóricos , Software
11.
Waste Manag ; 118: 180-189, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32892094

RESUMO

In the U.S., about 27 million metric tons of municipal solid waste are used as fuel in Waste-to-Energy (WTE) power plants, generating about seven million tons of mixed bottom ash and fly ash (combined ash) annually, which are disposed of in landfills after metal separation. This study assessed the effect of using combined ash as a substitute of mined stone aggregates on the mechanical properties and leachability of cement mortar and concrete. The as-received combined ash was separated into three fractions: fine (<2 mm), medium (2-9.5 mm), and coarse (9.5-25 mm). The substitution of up to 100% of stone aggregate by the coarse and medium fractions of combined ash produced concrete with compressive strength exceeding 28 MPa after 28 days of curing. Similar results were obtained when the fine combined ash was used as a sand substitute, at 10 wt%, in mortar. The concrete specimens were subjected to several days of curing and mechanical testing. The results were comparable to the properties of commercial concrete products. The mechanical test results were supplemented by XRD and SEM analysis, and leachability tests by EPA Method 1313 showed that the optimal concrete products effectively immobilized the heavy metals in the combined ash.


Assuntos
Cinza de Carvão , Materiais de Construção , Força Compressiva , Incineração , Centrais Elétricas , Resíduos Sólidos
12.
Waste Manag ; 118: 323-330, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32920495

RESUMO

Effective minimisation of construction material waste has demonstrated that environmental pollution arising from construction activities can be reduced. Yet, there is insufficient knowledge on the role of architects in minimising waste, especially at the design phase. The purpose of this article is to identify the causes, barriers, approaches, driving factors to waste minimisation and to investigate strategies employed by architects at the design phase. This study adopted a survey questionnaire with both open and close-ended questions to elicit information from architects in Akure, Ondo State, Nigeria. Empirical results indicate that the major cause of waste at the design phase is the client's last minutes changes to design. Lack of training and design for flexibility and adaptability were the top barrier and approach to construction waste minimisation respectively. The driving factors were training, waste management policy and legislation while the top three strategies employed by the architects are modular coordination, proper detailing and market survey. Findings recommend that a design checklist be created and implemented, that waste minimisation options be considered and that architects take more responsibility for their actions during the design phase.


Assuntos
Gerenciamento de Resíduos , Materiais de Construção , Poluição Ambiental , Conhecimento , Nigéria
13.
Waste Manag ; 118: 510-520, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32980730

RESUMO

The extensive exploitation of natural resources, together with an inefficient use of end-of-life materials, results in the generation of vast amounts of waste. The current material streams are to be reconsidered to mitigate the environmental burdens and achieve the sustainability goals. However, these intentions usually lead to material downcycling, which does not provide significant environmental benefits. In this paper, the potential of waste brick recycling is assessed from the environmental point of view as the recycling options of waste bricks attract an eminent attention due to rationalization and optimization of material streams, including transformation to the circular economy model according to the EU commitments. Three different scenarios are taken into account in that respect: replacement of natural aggregate, partial replacement of cement binder, and alkaline activation. The life cycle methodology is used at the assessment and the obtained results are presented on both midpoint and endpoint levels. The analysis of environmental impacts shows only minor improvements resulting from the replacement of natural aggregates by recycled waste bricks. The partial replacement of cement by waste bricks in powdered form can provide the most substantial benefits including decarbonization of the construction sector. The application of alkaline activators can harm the potential of alkali-activated materials considerably due to their negative effects on human health. A complex assessment of recycling scenarios is found to preferable to one-sided analyses aimed at carbon dioxide emission reduction only if a real sustainability without any hidden risks is to be achieved.


Assuntos
Indústria da Construção , Gerenciamento de Resíduos , Materiais de Construção , Meio Ambiente , Humanos , Resíduos Industriais , Reciclagem
14.
PLoS One ; 15(9): e0237797, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870919

RESUMO

In this study, the effect of glazing-to-total-wall-area ratio on the thermal performance of different wall materials is numerically investigated in terms of heat transmission load. The investigation was performed for a South-facing wall in Elazig, Turkey. The heat transmission load through walls and windows are determined separately for summer and winter climate conditions. In this analysis, the frame area of the window is not considered. Therefore, whereas the glazing area on uninsulated and insulated walls is increased from 0% to 100%, the heat gain and losses are calculated separately according to the glazing type. The transmission loads through the wall are determined by an implicit finite difference procedure under steady periodic conditions. Concrete, briquettes, bricks, and autoclaved aerated concrete are selected as structure materials. Results show that in the uninsulated wall, the wall material affected the glazing area, whereas in the insulated wall, the effect of wall material on glazing area is insignificant.


Assuntos
Materiais de Construção , Temperatura , Ar , Luz Solar , Turquia
15.
PLoS One ; 15(9): e0238817, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32886701

RESUMO

Bio-asphalt binders have been proposed as replacements for traditional asphalt binders, owing to advantages such as environmental protection, low costs, and abundant resources. However, a limitation of bio-asphalt binders is that their high-temperature performance is not suitable for pavement construction. In recent years, nano-particles have been widely used to improve the pavement performance of asphalt binders, particularly the high-temperature performance. Thus, the nano-particles might also provide a positive modified effect on the high-temperature performance of bio-asphalt binders. Based on this, five types of nano-particles including SiO2, CaCO3, TiO2, Fe2O3, and ZnO are selected for the preparation of modified bio-asphalt binders, using different dosages of nano-particles and bio-oil. The high- and low-temperature performances, aging resistance, workable performance, and water stability of the nano-modified bio-asphalt binders and mixtures are investigated. The results reveal that, the high-temperature performance and aging resistance of the nano-modified bio-asphalt binders and mixtures are improved at increased nano-particle dosages, whereas their low-temperature performance is slightly weakened. The effects of the nano-particles on the workable performance and water stability are insignificant.


Assuntos
Materiais de Construção , Hidrocarbonetos/química , Carbonato de Cálcio , Temperatura Baixa , Compostos Férricos , Temperatura Alta , Nanopartículas Metálicas/química , Nanopartículas/química , Dióxido de Silício
16.
Environ Sci Pollut Res Int ; 27(34): 43389-43395, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32965644

RESUMO

Radon exhaled from building material surfaces is an important source of indoor radon. Yangjiang, located in the southern part of mainland China, is well-known as a high background radiation area (HBRA). Rather, high levels of radon and thoron concentration have been observed in adobe and brick houses. Reducing the indoor radon concentration remains an important issue in the high background radiation areas of China and the world. Generally, the walls of Chinese dwellings are solid. In this paper, a simple one-dimensional model for predicting the radon diffusion in a cavity wall is proposed, and an analysis formula describing the radon exhalation rate from cavity wall surfaces is presented. The influence on the radon exhalation rate due to leakage through structural joints and building material cracks is analyzed. The simulation results indicate that the radon exhalation rate from a cavity wall surface is far lower than that from a solid wall. The structure of cavity walls themselves is therefore useful as a mechanism for reducing the indoor radon in high background radiation areas across the world.


Assuntos
Poluentes Radioativos do Ar , Poluição do Ar em Ambientes Fechados , Monitoramento de Radiação , Radônio , Poluentes Radioativos do Ar/análise , Poluição do Ar em Ambientes Fechados/análise , Radiação de Fundo , China , Materiais de Construção , Expiração , Habitação , Radônio/análise
17.
J Environ Manage ; 276: 111196, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32862114

RESUMO

Advancements in product design towards increasingly more compact and efficient systems have created challenges for recycling and materials recovery due to lack of appropriate infrastructure and mechanisms for collection as well as lack of appropriate materials recovery mechanisms and processes for discarded consumer goods. During the period from 1960 to 2015, the world population has increased from about 3 billion to over 6 billion. During the same period, the municipal solid waste quantities have more than doubled globally (from 1.5 million tons/day in 1960 to 4.0 million tons/day in 2015). Due to relatively short use times, especially for high tech consumer products, the number of obsolete products and waste quantities have been increasing exponentially. The American Chemical Society has identified 44 of the 118 elements in the periodic table as endangered and to become extinct in their ore forms within the next 80 years. Nine elements are in serious threat of extinction in the next 100 years, 7 are in rising threat from increasing use elements, and 28 are in future risk of supply. Some elements used in high tech products and industrial applications (e.g., cordless power goods, LCD displays, wind turbines, magnets, rechargeable batteries, smartphones) have shown significant oscillations in their prices during the last decade. Price oscillations for some elements are likely to occur more frequently and with increasing amplitudes in the coming decades as their availability is jeopardized due to increasing demand as well as political and economic challenges for materials supply. Mechanisms for establishing effective waste management and recycling infrastructures for discarded products, similar to that of supply chain management, are needed for sustainable use and management of available material ores on Earth's crust that can support the infusion of technology and use in consumer products.


Assuntos
Reciclagem , Gerenciamento de Resíduos , Materiais de Construção , Fontes de Energia Elétrica , Resíduos Sólidos
18.
Artigo em Inglês | MEDLINE | ID: mdl-32824451

RESUMO

Due to the rapid growth of the construction industry's global environmental impact, especially the environmental impact contribution of bridge structures, it is necessary to study the detailed environmental impact of bridges at each stage of the full life cycle, which can provide optimal data support for sustainable development analysis. In this work, the environmental impact case of a three-tower cable-stayed bridge was analyzed through openLCA software, and more than 23,680 groups of data were analyzed using Markov chain and other research methods. It was concluded that the cable-stayed bridge contributed the most to the global warming potential value, which was mainly concentrated in the operation and maintenance phases. The conclusion shows that controlling the exhaust pollution of passing vehicles and improving the durability of building materials were the key to reducing carbon contribution and are also important directions for future research.


Assuntos
Carbono , Rios , China , Materiais de Construção , Emissões de Veículos
19.
Artigo em Inglês | MEDLINE | ID: mdl-32824551

RESUMO

The amount of building floor space (BFS) plays a key role in the energy and material demand prediction. Unfortunately, BFS estimation has faced the challenge of ineffective and inadequate approaches, and thus reliable data concerning China's BFS is unavailable. This study proposes a new estimation method for China's BFS and then estimates historical BFS by type in China from 1996 to 2014. The results show that total Chinese BFS grew from 28.1 billion m2 in 1996 to 61.3 billion m2 in 2014, increasing more than twice, with an annual growth rate of 4.4% from 1996 to 2014. During 1996-2014, urban residential BFS witnessed the highest annual increase rate (9.3%), while the growth rate for commercial and rural residential BFS was lower: 4.4% and 1.6%, respectively. By comparing with available statistics data, this study finds the model deviations are well below 5%, which indicates the reliability of the proposed method and robustness of the results. The proposed method not only can address the deficiencies of statistic yearbook and overcome the shortages of previous estimation approaches but also can derive more accurate and reliable data. This study lays a sound basis for the following study on building stock and building energy efficiency work.


Assuntos
Arquitetura de Instituições de Saúde , China , Conservação de Recursos Energéticos , Materiais de Construção , Humanos
20.
J Environ Manage ; 271: 110884, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32778256

RESUMO

This paper focuses on the functionalization of heterogeneous and highly contaminated waste material, namely bottom ashes (BA) with a particle size ≤ 125 µm that cannot be recycled with conventional treatments. The main goal of this study is to modify this waste into a valuable material that can be used in various applications, especially in the building sector. The complex mineralogical nature of this material was investigated with quantitative XRD, which confirms the presence of crystalline and amorphous phases such as silicates, carbonates, metallic oxides and amorphous glass. A hydrophobic modification was performed by using a fluorosilane grafting agent that utilizes the reactive surface sites of these minerals to form silanol bonds. Results showed that the 2.5% (m/m) of silane made the BA hydrophobic. Moreover, a thorough characterization showed that fluorosilane was well-grafted at the surface of the BA, with more than 60% of the fluorosilane chemisorbed on the surface. Additionally, the hydrophobic modification led to a significant decrease of the leaching of the contaminants (Cr, Cu, Mo and Sb) from the BA particles. Following this methodology, fine fraction of BA could be eventually used as a building material, preventing the landfill of this toxic waste.


Assuntos
Cinza de Carvão , Incineração , Carbonatos , Materiais de Construção , Resíduos Sólidos
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