92 research outputs found
Life cycle greenhouse gas emissions of blended cement concrete including carbonation and durability
The final publication is available at Springer via http://dx.doi.org/10.1007/s11367-013-0614-0Purpose Blended cements use waste products to replace
Portland cement, the main contributor to CO2 emissions in
concrete manufacture. Using blended cements reduces the
embodied greenhouse gas emissions; however, little attention
has been paid to the reduction in CO2 capture (carbonation)
and durability. The aim of this study is to determine if the
reduction in production emissions of blended cements compensates
for the reduced durability and CO2 capture.
Methods This study evaluates CO2 emissions and CO2 capture
for a reinforced concrete column during its service life
and after demolition and reuse as gravel filling material.
Concrete depletion, due to carbonation and the unavoidable
steel embedded corrosion, is studied, as this process consequently
ends the concrete service life. Carbonation deepens
progressively during service life and captures CO2 even after
demolition due to the greater exposed surface area. In this
study, results are presented as a function of cement replaced
by fly ash (FA) and blast furnace slag (BFS).
Results and discussion Concrete made with Portland cement,
FA (35%FA), and BFS blended cements (80%BFS) captures
47, 41, and 20 % of CO2 emissions, respectively. The service
life of blended cements with high amounts of cement replacement,
like CEM III/A (50 % BFS), CEM III/B (80 % BFS),
and CEMII/B-V (35%FA), was about 10%shorter, given the
higher carbonation rate coefficient. Compared to Portland
cement and despite the reduced CO2 capture and service life,
CEM III/B emitted 20 % less CO2 per year.
Conclusions To obtain reliable results in a life cycle assessment,
it is crucial to consider carbonation during use and
after demolition. Replacing Portland cement with FA, instead
of BFS, leads to a lower material emission factor, since
FA needs less processing after being collected, and transport
distances are usually shorter. However, greater reductions
were achieved using BFS, since a larger amount of cement
can be replaced. Blended cements emit less CO2 per year
during the life cycle of a structure, although a high cement
replacement reduces the service life notably. If the
demolished concrete is crushed and recycled as gravel filling
material, carbonation can cut CO2 emissions by half. A case
study is presented in this paper demonstrating how the results
may be utilized.This research was financially supported by the Spanish Ministry of Science and Innovation (research project BIA2011-23602). The authors thank the anonymous reviewers for their constructive comments and useful suggestions. The authors are also grateful for the thorough revision of the manuscript by Dr. Debra Westall.García Segura, T.; Yepes Piqueras, V.; Alcalá González, J. (2014). Life cycle greenhouse gas emissions of blended cement concrete including carbonation and durability. International Journal of Life Cycle Assessment. 19(1):3-12. https://doi.org/10.1007/s11367-013-0614-0S312191Aïtcin PC (2000) Cements of yesterday and today: concrete of tomorrow. Cem Concr Res 30(9):1349–1359Angst U, Elsener B, Larsen C (2009) Critical chloride content in reinforced concrete—a review. Cement Concr Res 39(12):1122–1138Berge B (2000) The ecology of building materials. Architectural Press, OxfordBertolini L, Elsener B, Pedeferri P, Polder R (2004) Corrosion of Steel in Concrete—Prevention Diagnosis. Repair, Wiley-VCH, WeinheimBörjesson P, Gustavsson L (2000) Greenhouse gas balances in building construction: wood versus concrete from life cycle and forest land-use perspectives. Energy Policy 28(9):575–588Camp CV, Huq F (2013) CO2 and cost optimization of reinforced concrete frames using a big bang-crunch algorithm. Eng Struct 48:363–372CEN (2011) EN 197–1: Cement. Part 1: Composition, specifications and conformity criteria for common cements. European Committee for Standardization, BrusselsCIWMB (2000) Designing with vision: a technical manual for materials choices in sustainable construction. California Integrated Waste Management Board, SacramentoCollins F (2010) Inclusion of carbonation during the life cycle of built and recycled concrete: influence on their carbon footprint. Int J Life Cycle Assess 15(6):549–556Database BEDEC (2012) Institute of Construction Technology of Catalonia. Barcelona, SpainDodoo A, Gustavsson L, Sathre R (2009) Carbon implications of end-of-life management of building materials. Resour Conserv Recy 53(5):276–286ECO-SERVE Network Cluster 3 (2004) Baseline Report for the Aggregate and Concrete Industries in Europe. European Commission, Hellerup: http://www.eco-serve.net/uploads/479998_baseline_report_final.pdf , accessed 10 September 2012European Federation of Concrete Admixtures Associations (2006) Environmental Product Declaration (EPD) for Normal Plasticizing admixtures. Environmental Consultant, Sittard: http://www.efca.info/downloads/324%20ETG%20Plasticiser%20EPD.pdf , accessed 13 October 2012Galán I (2011) Carbonatación del hormigón: combinación de CO2. Dissertation, Universidad Complutense de Madrid, SpainGalán I, Andrade C, Mora P, Sanjuan MA (2010) Sequestration of CO2 by concrete carbonation. Environ Sci Technol 44(8):3181–3186Flower DJM, Sanjayan JG (2007) Greenhouse gas emissions due to concrete manufacture. Int J Life Cycle Assess 12(5):282–288Guzmán S, Gálvez JC, Sancho JM (2011) Cover cracking of reinforced concrete due to rebar corrosion induced by chloride penetration. Cement Concr Res 41(8):893–902Houst YF, Wittmann FH (2002) Depth profiles of carbonates formed during natural carbonation. C Cement Concr Res 32(12):1923–1930Institute for Diversification and Energy Saving (2010) Conversion factors of primary energy and CO2 emissions of 2010. M. Industria, Energía y Turismo, Madrid, Spain: http://www.idae.es/index.php/mod.documentos/mem.descarga?file=/documentos_Factores_Conversion_Energia_y_CO2_2010_0a9cb734.pdf , accessed 10 September 2012ISO (2005) ISO/TC 71—Business plan. Concrete, reinforced concrete and prestressed concrete. International Organization for Standardization (ISO), Geneva, SwitzerlandISO (2006) ISO 14040: Environmental management—life-cycle assessment—principles and framework. International Organization for Standardization, Geneva, SwitzerlandJiang L, Lin B, Cai Y (2000) A model for predicting carbonation of high-volume fly ash concrete. Cement Concr Res 30(5):699–702Jönsson A, Björklund T, Tillman AM (1988) LCA of concrete and steel building frames. Int J Life Cycle Assess 3(4):216–224Knoeri C, Sanyé-Mengual E, Althaus HJ (2013) Comparative LCA of recycled and conventional concrete for structural applications. Int J Life Cycle Assess 18(5):909–918Lagerblad B (2005) Carbon dioxide uptake during concrete life-cycle: State of the art. Swedish Cement and Concrete Research Institute, StockholmLeber I, Blakey FA (1956) Some effects of carbon dioxide on mortars and concrete. J Am Concr Inst 53:295–308Fomento M (2008) EHE-08; Code of Structural Concrete. M. Fomento, Madrid, SpainMarinkovic S, Radonjanin V, Malešev M, Ignjatovic I (2010) Comparative environmental assessment of natural and recycled aggregate concrete. Waste Manag 30(11):2255–2264Martinez-Martin FJ, Gonzalez-Vidosa F, Hospitaler A, Yepes V (2012) Multi-objective optimization design of bridge piers with hybrid heuristic algorithms. J Zhejiang Univ-SCI A 13(6):420–432O’Brien KR, Ménaché J, O’Moore LM (2009) Impact of fly ash content and fly ash transportation distance on embodied greenhouse gas emissions and water consumption in concrete. Int J Life-cycle Assess 14(7):621–629Pade C, Guimaraes M (2007) The CO2 uptake of concrete in a 100-year perspective. Cem Concr Res 37(9):1384–1356Papadakis VG, Vayenas CG, Fardis MN (1991) Fundamental modeling and experimental investigation of concrete carbonation. ACI Mater J 88(4):363–373Payá I, Yepes V, González-Vidosa F, Hospitaler A (2008) Multiobjective optimization of reinforced concrete building by simulated annealing. Comput-Aided Civ Inf 23(8):596–610Payá-Zaforteza I, Yepes V, Hospitaler A, González-Vidosa F (2009) CO2-efficient design of reinforced concrete building frames. Eng Struct 31(7):1501–1508Saassouh B, Lounis Z (2012) Probabilistic modeling of chloride-induced corrosion in concrete structures using first- and second-order reliability methods. Cement Concrete Comp 34(9):1082–1093The Concrete Centre (2009) The Concrete Industry Sustainability Performance Report. The Concrete Center, Camberley: http://www.admixtures.org.uk/downloads/Concrete%20Industry%20Sustainable%20Performance%20Report%202009.pdf , accessed 9 September 2012Tuutti K (1982) Corrosion of steel in Concrete. CBI Forskning Research Report, Swedish Cem Concr Res Inst. Stockholm, SwedenWeil M, Jeske U, Schebek L (2006) Closed-loop recycling of construction and demolition waste in Germany in view of stricter environmental threshold values. Waste Manage Res 24(3):197–206World Steel Association (2010) Fact sheet: the three Rs of sustainable Steel. World Steel Association, Brussels: http://www.steel.org/Sustainability/~/media/Files/SMDI/Sustainability/3rs.ashx , accessed 15 September 2012Worrell E, Price L, Martin N, Hendriks C, Meida LO (2001) Carbon dioxide emissions from the global cement industry. Annu Rev Energy Environ 26:303–329Yepes V, González-Vidosa F, Alcalá J, Villalba P (2012) CO2-optimization design of reinforced concrete retaining walls based on a VNS-threshold acceptance strategy. J Comput Civ Eng 26(3):378–386Yiwei T, Qun Z, Jian G (2011) Study on the Life-cycle Carbon Emission and Energy-efficiency Management of the Large-scale Public Buildings in Hangzho. China. International Conference on Computer and Management, Wuhan, pp 546–552Zornoza E, Payá J, Monzó J, Borrachero MV, Garcés P (2009) The carbonation of OPC mortars partially substituted with spent fluid catalytic catalyst (FC3R) and its influence on their mechanical properties. Const Build Mater 23(3):1323–132
Twenty-Five Years of Convoluted Health Reforms in Mexico
Núria Homedes and Antonio Ugalde discuss 25 years of reform to the Mexican health care system and argue that although costs and accessibility have increased, health inequities, efficiency, productivity, and quality of care have not improved
Antipsychotic withdrawal symptoms: Phenomenology and pathophysiology
The authors review the literature discribing non-dyskinetic antipsychotic withdrawal phenomena. Withdrawal of these agents can cause nausea, emesis, anorexia, diarrhea, rhinorrhea, diaphoresis, myalgia, paresthesia, anxiety, agitation, restlessness, and insomnia. Psychotic relapse is often presaged by increased anxiety, agitation, restlessness and insomnia, but the temporal relationship of these prodromal symptoms to reduction in the dosage or discontinuation of neuroleptics distinguishes them from the effects of abrupt withdrawal.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65190/1/j.1600-0447.1988.tb05116.x.pd
In Vitro and In Vivo Efficacy of Ether Lipid Edelfosine against Leishmania spp. and SbV-Resistant Parasites
Leishmaniasis represents a major international health problem, has a high morbidity and mortality rate, and is classified as an emerging and uncontrolled disease by the World Health Organization. The migration of population from endemic to nonendemic areas, and tourist activities in endemic regions are spreading the disease to new areas. Unfortunately, treatment of leishmaniasis is far from satisfactory, with only a few drugs available that show significant side-effects. Here, we show in vitro and in vivo evidence for the antileishmanial activity of the ether phospholipid edelfosine, being effective against a wide number of Leishmania spp. causing cutaneous, mucocutaneous and visceral leishmaniasis. Our experimental mouse and hamster models demonstrated not only a significant antileishmanial activity of edelfosine oral administration against different wild-type Leishmania spp., but also against parasites resistant to pentavalent antimonials, which constitute the first line of treatment worldwide. In addition, edelfosine exerted a higher antileishmanial activity and a lower proneness to generate drug resistance than miltefosine, the first drug against leishmaniasis that can be administered orally. These data, together with our previous findings, showing an anti-inflammatory action and a very low toxicity profile, suggest that edelfosine is a promising orally administered drug for leishmaniasis, thus warranting clinical evaluation
Assessing capacity for health policy and systems research in low and middle income countries*
BACKGROUND: As demand grows for health policies based on evidence, questions exist as to the capacity of developing countries to produce the health policy and systems research (HPSR) required to meet this challenge. METHODS: A postal/web survey of 176 HPSR producer institutions in developing countries assessed institutional structure, capacity, critical mass, knowledge production processes and stakeholder engagement. Data were projected to an estimated population of 649 institutions. RESULTS: HPSR producers are mostly small public institutions/units with an average of 3 projects, 8 researchers and a project portfolio worth 100,000 or more, but they account for 54% of total funding. International sources and national governments account for 69% and 26% of direct project funding, respectively. A large proportion of international funds available for HPSR in support of developing countries are either not spent or spent through developed country institutions. CONCLUSIONS: HPSR producers need to increase their capacity and critical mass to engage effectively in policy development and to absorb a larger volume of resources. The relationship between funding and critical mass needs further research to identify the best funding support, incentives and capacity strengthening approaches. Support should be provided to network institutions, concentrate resources and to attract funding
Estudio socioeconómico del Sector Nueva Colombia del municipio de Chiquinquirá, Boyacá, a partir de variables de la contabilidad social
Spa: El presente documento contiene la aplicación conceptual de la contabilidad social, metodología desarrollada por Jack Araújo en el libro Contabilidad Social (1995), este autor fue el referente con el propósito de estudiar las características demográficas y económicas del sector Nueva Colombia, ubicado en el barrio El Bosque, del municipio de Chiquinquirá, departamento de Boyacá.PregradoContador Públic
Sediment characteristics and internal architecture of offshore sand ridges on a tideless continental shelf (western Mediterranean)
15 pages, 13 figuresAn integrated approach combining swath bathymetry, an extensive dataset of vibrocores and high‐resolution seismic reflection data was used to assess the origin and evolution of offshore sand ridges on a tideless continental shelf (Gulf of Valencia, western Mediterranean). The sand ridges are located in the mid‐outer shelf at 55–85 m water depth, obliquely oriented to the shoreline. They are 1.5 to 7 m high, with a wavelength between 600 and 1,100 m and a mean height‐to‐wavelength ratio of 0.004. The sand ridges are composed of well‐sorted medium sand and are partially covered by a mud layer, evidencing a moribund stage. They overlie an erosion surface that locally crops out at the seafloor and is interpreted as the Holocene wave‐ravinement surface. In the sediment cores, this surface corresponds to an erosional lag composed of coarse sand and gravel with pebbles. Small topographic irregularities on this surface are interpreted as shoreline‐associated features that may act as the precursor for ridge development. Their preservation within the sand ridges could be related to the hardness of these features. Internally, the sand ridges display high‐angle dipping reflections, indicating ridge migration towards the southeast in the direction of the present‐day sediment transport direction. The presence of interbedded mud layers, associated with these reflections, indicates intermittent episodes of mud deposition when active. The internal architecture of some small ridges also provides new insights into their transition from an active to moribund state, as evidenced by a change in the geometry of the internal units from progradational to aggradational, finally being overlain by onlapping finer deposits over the flanks and in the troughs. The Gulf of Valencia sand ridge field constitutes a valuable potential sand resource of 22 million m3 of well‐sorted medium and coarse sand with limited mud content, which must be preserved as a strategic sand reservoir. © 2020 John Wiley & Sons, LtdThis research was supported by the projects FORMED (CGL2012-33989) and COSTEM (CTM2009-07806). [...] R. Durán is supported by the Ocean and Littoral Sedimentary Process Consolidated http://mc.manuscriptcentral.com/esp Earth Surface Processes and Landforms For Peer Review Research Group by the Generalitat de Catalunya grant (2017 SGR-863)With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)Peer reviewe
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