Research ArticleCarbon Footprint of Recycled Aggregate Concrete
Luis F Jimenez Jose A Domınguez and Ricardo Enrique Vega-Azamar
Chetumal Institute of Technology Avenida Insurgentes No 330 77050 Chetumal QROO Mexico
Correspondence should be addressed to Luis F Jimenez fjtorrezitchetumaledumx
Received 30 August 2017 Accepted 23 April 2018 Published 30 May 2018
Academic Editor Ghassan Chehab
Copyright copy 2018 Luis F Jimenez et alis is an open access article distributed under the Creative CommonsAttribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited
Carbon footprint is one of the most widely used tools for assessing the environmental impacts of the production and utilization ofconcrete as well as of the components derived from it representing the amount of carbon dioxide and other greenhouse gasesassociated with this product expressed as CO2 equivalents In this paper carbon footprint was used to compare the environmentalperformance in the production phase of a concrete made with both recycled and crushed virgin limestone aggregates using a lifecycle analysis methodological approach Research outcomes revealed as expected that carbon dioxide equivalent emissionsdecreased slightly as the use of recycled aggregates increased Emissions for concrete with 05 wc were between 347 and 351 kg ofCO2-em3 It was also corroborated that cement is the material with the greatest influence on greenhouse gas emission generationin the concretersquos production phase regardless of the use of recycled or virgin aggregates
1 Introduction
e construction industry constitutes a substantial develop-ment factor for the so-called emerging economies but at thesame time it is one of the main sources of waste generationsince in its processes many materials associated with otherindustrial sectors are used such as cement steel stonecardboard glass wood aluminum plastics and ceramicsamong others Natural resource consumption to sustain thatindustryrsquos growth increases steadily contributing to envi-ronmental deterioration for example the rise in the atmo-spherersquos temperature as well as that of the oceans which hasled to the well-known climate crisis of global warming [1]
Building materials such as concrete are increasinglybeing questioned for their environmental impact becauseconstruction and demolition waste is a major component ofall the waste generated by the construction industry and toreduce the pressure on the exploitation natural resourcesindustry has focused on finding greener ways to produceconcrete encouraging the use of recycled materials to re-place virgin materials [2]
In the last decades a reduction of natural resourceconsumption in the production of aggregates through con-crete debris recycling has been sought so that new aggregatescan be obtained which replace the usual aggregates coming
from the crushing of virgin limestone [3] which even offerseconomic advantages because when comparing costs ofrecycled aggregates with normal aggregates savings of almost4 USD (26) per m3 of aggregate and almost 6 USD (9) perm3 of concrete can be obtained [4]
However in view of the diversity and variability of therecycled aggregatesrsquo properties there is a lack of consensusregarding the concretersquos behavior when this kind of ag-gregates is used so it is necessary to evaluate the feasibility ofusing them from an environmental perspective which canbe achieved through the application of a life cycle assessment(LCA) methodological approach
LCA in concrete fabrication has been used by some re-searchers to assess the environmental impact generated in thecement production process and in the extraction of stonematerial to obtain aggregates [5] is has resulted in thesearch for alternate materials such as fly ash slag and ag-gregates recovered from construction and demolition waste(CDW) which has given rise to theGreen Concrete notion [6]
An important tool to evaluate the environmental im-pacts generated by the concrete production and its com-ponents within the LCA methodology is the carbonfootprint e carbon footprint has its roots in the ecologicalfootprint concept originally it was expressed through thearea required for assimilating the CO2 emissions generated
HindawiAdvances in Civil EngineeringVolume 2018 Article ID 7949741 6 pageshttpsdoiorg10115520187949741
during the life cycle of manufactured products However asthe global warming problem became a priority on the in-ternational agenda the concept and method of carbonfootprint have changed it no longer represents an area butthe amount of greenhouse gases (GHGs) associated witha product or service throughout its life cycle ena productrsquos carbon footprint consists of the LCA limited tothe emissions that have an eect on climate change eproperty often referred to as carbon footprint is the weightin kilograms or tons of GHG emissions per person productor activity for which an emissions inventory is required [7]
Several authors around the world have reported theadvantages of using recycled materials in the reduction ofGHG In Taiwan LCA in the rehabilitation of pavementsusing recycled materials was evaluated e conventionalmaterials replaced by recycled materials were crushed stone(67) sand (50) and asphalt cement (70) e resultsrevealed GHG reductions of 16 to 23 [8] In a study de-veloped in Hong Kong GHG reductions ranged from 6 to17 in the construction of concrete buildings using variousrecycled materials such as recovered stone aggregates bricksand concrete blocks plastics asphalts and galvanized steelsamong others [9] In Australia a GHG reduction about10 was determined when geopolymers replaced ordinaryportland concrete (OPC) in the manufacture of concrete[10] Recently in the USA Asutosh and Nawari [11] rep-orted that the use of recycled materials in pavement con-struction reduces GHG emissions about 12
In spite of this evidence great care must be taken in thedevelopment of this kind of studies since small variations inthe goals and objectives denition data gathering frominventories and the election of the impact analysis meth-odology may cause important dierences in the environ-mental qualication obtained during the interpretation ofresults phase According to all of the above the main ob-jective of the present work was to evaluate the environmentalsustainability of a concrete produced with both virgin andrecycled aggregates through the comparison of its carbonfootprint expecting that CO2 emissions decrease when theamount of recycled coarse aggregate in the mix increasesduring the concrete manufacturing process
2 Materials and Methods
In the present study the concretersquos carbon footprint in-volved the quantication of the GHG released throughoutthe manufacturing process including material supply eGHGs were mainly carbon dioxide (CO2) methane (CH4)and nitrous oxide (N2O) which have impact on globalwarming In this work the environmental impact was cal-culated from eld data and from the data obtained in dif-ferent inventories following the internationally recognizedstandard ISO 14064-1 [12] In this way it was possible toknow the carbon dioxide equivalent mass (CO2-e) originatedduring the concrete manufacturing process e study wasperformed according to the framework shown in Figure 1
Objectives and scope included both the exact denitionof the system under study and the depth of the study In-ventory analysis consisted in the data collection to quantify
material and energy inputs and outputs of the studied systemImpact and damage assessment was related to the identi-cation characterization and quantication of the eects ofthe studied system on the environment In the interpretationof results phase signicant points were identied based on theoutcomes from the previous phases corroborating theirintegrity sensitivity and coherence sustaining the conclu-sions and recommendations of the study on the base of theinherent limitations of the work
21 Scope and System Limits e analysis was focused onthe aggregate production for the concrete manufacture neand coarse aggregate coming from crushed virgin lime-stone and recycled coarse aggregate obtained from thetrituration and classication of concrete debris Limestone isthe most common in the study region (Yucatan Mexico)Five concrete mixes were produced with a watercementratio (wc) of 05 and other ve mixes with a wc of 07 Fivereplacement rates of virgin coarse aggregate by recycledcoarse aggregate (R) were used 0 25 50 75 and 100OPC was used in all mixtures and its production processwas considered independently from the rest of the materials
e material was collected selectively in CDW landllsleaving it free of undesirable residues such as steel and plasticsamong others CDWcomposition is very diverse from one placeto another and depends on the construction processes availablematerials and population customs e most common com-ponents of CDW are concrete and mortar masonry ceramicbrvbaroors wood plastics and metals Dierent authors in severalparts of the world agree that the rst three predominate whichare the main raw material for recycling processes reachingbetween 30 and 40 of total waste [13 14]
In this research only debris from structural elements suchas slabs beams and columns was selected Subsequentlyreinforcement steel wires ducts and other electric materialwere dismantled and the material was brushed to cleanimpurities such as earth and vegetable remains e extractedrawmaterial was taken to an impact mill plant for grinding sothat coarse recycled aggregate could be obtained In the sameplant the virgin material coming from a bank was crushed toobtain the ne and coarse aggregates and then the tests werecarried out In Tables 1 and 2 aggregate properties andmixture design are indicated
Objectives and scope
Inventory analysis
Impact and damage assessment
Result interpretation
Figure 1 Framework for carbon footprint assessment
2 Advances in Civil Engineering
Figure 2 shows the CO2-e emission system for theproduction of 1m3 of concrete (both regular and recycled)Raw material refers to limestone and water e differencebetween both concrete types is that in order to produce therecycled aggregate mix concrete debris extracted fromCDW is also used
22 Inventory Analysis is phase involved data collectionand calculation procedures to quantify the systemrsquos inputsand outputs Data collection was classified into two levels
221 Level 1 In this level energy consumption and otherresources are obtained from the operating facilitiesrsquo pro-cessing logs which include yields and resource consumptionrates at the time of the facilityrsquos operation activities ey aretypically derived from the use of a fossil fuel (diesel) for theraw material transport In this case it refers to vehicle fuelconsumption for the transportation of the materials as wellas the limestonersquos exploitation rates and volumes use ofexplosives and water that generate CO2-e emissions
222 Level 2 In this level CO2-e emission factors formaterialproduction were determined ey are induced indirectly bythe activity under analysis not emitted in the place where theactivity was carried out since they were derived from sourcesnot directly controlled In this case these were associated withcement production energy consumption and utilization ratesof materials for the manufacture of concrete ey were col-lected from different databases as indicated in Table 3
Table 3 shows an average emission factor of 745 kgCO2-eton for OPC average [15] e value of 612 kg CO2-
eton reported in 2013 by the main cement producer inMexico [19] was rejected because in that report thecompany does not indicate the methodology used for theemission factor calculation and on the contrary it differsmarkedly from what is reported in other countries witha higher degree of industrialization and technologicalprogress where the estimated emission factor ranges from800 to 850 kg CO2-eton of cement as in GermanyFrance Denmark and other European Union countries[20ndash23] Total amount of CO2-em3 emissions of concretecorresponded to the sum of the emissions from cementproduction aggregates water casting and concrete place-mentese components required the use of limestone waterelectricity diesel fuel and explosives e latter refers toamixture of low-density explosive agents and other additionalelements such as fulminant and wicks used during blastingwork
3 Results and Discussion
Carbon footprint assessment for each concrete mixexpressed in kg CO2-em3 is summarized in Table 4 whichincludes total cement aggregates and other nonsignificantemissions such as the use of water and explosive agents
Calculations were made from the following equation
where Q corresponds to the material quantity or input usedand F represents the emission factor for the production of1m3 of concrete Also in Table 4 the results of compressivestrength (Fc) for each concrete mixture expressed in MPahave been included to show their relationship with CO2-eemissions
In the Partial column of Table 2 the sum of emissions isregistered excluding the cement contribution since thismaterial generates most of the total emissions when com-pared to the rest of the elements with more than 80(Figure 3) similar to what was reported by Marincovic et al[24]
On the contrary the influence of fine and coarse ag-gregates has been compared in Figure 4 where it can beappreciated that recycled coarse aggregate has a slight lowercontribution than virgin gravel with a difference of 3
As expected because of the difference in the cementcontent the carbon footprint of the mix with 05 wc was25 higher than that of the mix with 07 wc e carbonfootprint of all the analyzed mixes decreased to a smallextent as the coarse aggregate R increased For the case ofthe concrete with 05 wc the values fluctuated between 347and 351 kg of CO2-em3 slightly lower than that reported byTurner and Collins [10] under similar conditions (354 kg ofCO2-em3 for a 06 wc) and than that reported by Kim et al(356 kg of CO2-em3 for a concrete with compressivestrength of 30MPa) [25]
Since the carbon footprint itself is an intermediate as-sessment point the impacts were converted to damage tohuman health is was determined considering that 1 kgCO2-e represents 21times 10minus7 DALY (disability-adjusted life
year) which expresses the number of years lost as a result oflack of health disability or premature death [26] Applyingthis conversion factor the obtained DALY values rangedfrom 729 to 736times10minus5 (about 385 minutes) for 05 wc andfrom 549 to 556times10minus5 (about 29 minutes) for 07 wc
ese results may seem insignicant at the global level asthey would need to be standardized and weighted consid-ering other impact categories such as eutrophicationacidication and land use change which is beyond the scopeof this research
Finally the construction industry generates a largeamount of waste either by the construction process itself orby demolition in fact it is the largest source of industrial
waste in developed countries which have been estimated ina range of 520 and 760 kgpersonyear without taking intoaccount wars or natural disasters [4] of this large volumeconcrete is the most abundant since it represents 67by weight If we consider an average of 640 kgpersonyearand the Yucatan Peninsula population of 417 million in-habitants by the year 2010 [27] theMexican region in whichmost of the limestone aggregates in the country are pro-duced a total concrete waste is 179 million tons per yearthat is around 744751 cubic meters per year If suchquantity were recycled this would imply that approximately22343 tons of CO2-e would cease to be emitted per year inthis region
Table 3 Inventory of CO2-e energy and materials
Input Factor Unit Context ReferenceCement 0745 kg CO2-ekg Mexico 2004 [15]ExplosivesYield 0465 kg productm3 Mexico 2014 [16]Emission 0440 kg CO2-ekg Australia 2013 [10]
DieselYield 3000 kmL Mexico 2014 [16]Emission 2680 kg CO2-eL Australia 2013 [10]
CoarseYield for normal 1320 m3 stone1000 kg Mexico 2014 [16]Yield for recycled 0002 m3 debriskg Mexico 2014 [16]Emission 0041 kg CO2-ekg Australia 2013 [10]
FineYield 1120 m3 stone1000 kg Mexico 2014 [16]Emission 0014 kg CO2-ekg Australia 2013 [10]
Electricity 0458 kg CO2-eKWH Mexico 2015 [17]Water 0540 KWHm3 Mexico 2011 [18]ConcreteCasting and laying 0012 kg CO2-ekg Australia 2013 [10]
CO2-e
Electricity
Diesel
Transport
ExplosivesCement
Coarse
Fine
Casting and laying
Concrete (1 m3)
Raw material
System boundary
Figure 2 CO2-e emission system for the concrete production
4 Advances in Civil Engineering
4 Conclusions
Specic conclusions of the present work are drawn basedupon the experimental results
(i) It was determined that CO2-e emissions decreaseslightly by increasing the percentage of recycledcoarse aggregates in the concretemixtures indicatingthat the use of this material has little inbrvbaruence on thereduction of the carbon footprint in the concretemanufacturing process
(ii) It was also conrmed that cement is the materialwith the greatest inbrvbaruence on greenhouse gasemissions in the production of concrete
(iii) If we consider the per capita generation average ofconcrete waste from the construction industry andthe population of the region where most of thelimestone aggregates in Mexico are produced therecycling of concrete waste would imply that ap-proximately 22343 tons of CO2-e would cease to beemitted annually in this region
(iv) Regarding the use of recycled aggregates in concreteproduction although the progress has been made inthe study of the physical mechanical and durabilityproperties of the material there is still a large area ofopportunity in the research of the environmentalimpacts involved Future research avenues shouldconsider the contributions of other cementitiousmaterials within a broader LCA framework in-cluding both the use stage and the nal disposal ofbuildings besides the construction stage
Conflicts of Interest
e authors declare that there are no conbrvbaricts of interestregarding the publication of this paper
Acknowledgments
e authors are very grateful to Triturados y Carpetas delSureste S A de C V for their support in the crushing ofstone material and measurement of energy consumption atits industrial plant in Yucatan Mexico
References
[1] R Reham and M Nehdi ldquoCarbon dioxide emissions andclimate change policy implications for cement industryrdquoEnvironmental Science and Policy vol 8 no 2 pp 105ndash1142005
[2] S Talukdar S T Islam and N Banthia ldquoDevelopment ofa lightweight low-carbon footprint concrete containing recy-cled waste materialsrdquo Advances in Civil Engineering vol 2011Article ID 594270 8 pages 2011
[3] L F Jimenez and E I Moreno ldquoDurability indicators in highabsorption recycled aggregate concreterdquo Advances in MaterialsScience and Engineering vol 2015 Article ID 5054238 pages2015
[4] J A Domınguez Lepe E Martınez Lobeck and V VillanuevaCuevas ldquoHormigones reciclados una alternativa sustentabley rentablerdquo Hormigon vol 867 pp 10ndash21 2004
[5] P Van den Heede and N De Belie ldquoEnvironmental impactand life cycle assessment (LCA) of traditional and lsquogreenrsquoconcretes literature review and theoretical calculationsrdquoCement and Concrete Composites vol 34 no 4 pp 431ndash4422012
[6] C Meyer ldquoe greening of the concrete industryrdquo Cementand Concrete Composites vol 31 no 8 pp 601ndash605 2009
[7] T Wiedmann and J Minx ldquoA denition of carbon footprintrdquoin Ecological Economics Research Trends Chapter 1C C Pertsova Ed pp 1ndash11 Nova Science PublishersHauppauge NY USA 2008
[8] C-T Chiu T-H Hsu andW-F Yang ldquoLife cycle assessmenton using recycled materials for rehabilitating asphalt pave-mentsrdquo Resources Conservations and Recycling vol 52 no 3pp 545ndash556 2008
[9] C K Chau W K Hui W Y Ng and G Powell ldquoAssessmentof CO2 emissions reduction in high-rise concrete officebuildings using different material use optionsrdquo ResourcesConservations and Recycling vol 61 pp 22ndash34 2012
[10] L K Turner and F G Collins ldquoCarbon dioxide equivalent(CO2-e) emissions a comparison between geopolymer andOPC cement concreterdquo Construction and Building Materialsvol 43 pp 125ndash130 2013
[11] A T Asutosh and N O Nawari ldquoIntegration of recycledindustrial wastes into pavement design and construction fora sustainable futurerdquo Journal of Sustainable Developmentvol 10 no 1 pp 9ndash23 2017
[12] International Organization for Standardization ISO 14064-1International Organization for Standardization GenevaSwitzerland 2006
[13] S C Angulo L F R Miranda and V M John ldquoConstructionand demolition waste its variability and recycling in Brazilrdquoin Proceedings of the International Conference on SustainableBuilding Oslo Norway April 2002
[14] N D Oikonomou ldquoRecycled concrete aggregatesrdquoCement and Concrete Composites vol 27 no 2 pp 315ndash318 2005
[15] Instituto Nacional de Ecologıa Inventario Nacional de Emi-siones de Gases de Efecto Invernadero 1990-2002 InstitutoNacional de Ecologıa Mexico 2004
[16] L F Jimenez Torrez Durabilidad del concreto con agregadoreciclado de alta absorcion PhD dissertation UniversidadAutonoma de Yucatan Merida Mexico 2015
[17] Secretarıa del Medio Ambiente y Recursos Naturales RegistroNacional de Emisiones Secretarıa delMedio Ambiente y RecursosNaturales Mexico 2015
[18] Comision Nacional para el Uso Eficiente de la EnergıaEstudio Integral de Sistemas de Bombeo de Agua PotableMunicipal Comision Nacional para el Uso Eficiente de laEnergıa Mexico 2011
[19] CEMEX SAB de CV Informe de Desarrollo SustentableCEMEX San Pedro Garza Garcıa Mexico 2013
[20] Oko-Institut ldquoApproximated EU GHG inventory proxyGHG emission estimates for 2013rdquo EEA Technical Report 16Oko-Institut Germany 2013
[21] Association Technique des Liants Hydrauliques Environ-mental Inventory of French Cement Production AssociationTechnique des Liants Hydrauliques Paris France 2012
[22] J S Damtoft J Lukasik D Hertfort D Sorrentino andE M Gartner ldquoSustainable development and climate changeinitiativesrdquo Cement and Concrete Research vol 38 no 2pp 115ndash127 2008
[23] A Josa A Aguado A Heino E Byars and A CardimldquoComparative analysis of available life cycle inventories ofcement in the EUrdquo Cement and Concrete Research vol 34no 8 pp 1313ndash1320 2004
[24] S Marincovic V Radonjanin M Malesev and I IgnjatovicldquoComparative environmental assessment of natural andrecycled aggregate concreterdquo Waste Management vol 30no 11 pp 2255ndash2264 2010
[25] T H Kim C U Chae G H Kim and H J Jang ldquoAnalysis ofCO2 emission characteristics of concrete used at constructionsitesrdquo Sustainability vol 8 no 4 p 348 2016
[26] M Goedkoop and R Spriensma 9e Eco-Indicator 99 ADamage Oriented Method for Life Cycle Impact Assessment
Methodology Report PRe Consultants Amersfoort Nether-lands 3rd edition 2011
[27] Mexicorsquos National Council of Population CONAPO De-mographic Dynamics 1990ndash2010 and Population Projections2010ndash2030 Mexicorsquos National Council of Population Mexico2014
Chemical EngineeringInternational Journal of Antennas and
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Navigation and Observation
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Submit your manuscripts atwwwhindawicom
during the life cycle of manufactured products However asthe global warming problem became a priority on the in-ternational agenda the concept and method of carbonfootprint have changed it no longer represents an area butthe amount of greenhouse gases (GHGs) associated witha product or service throughout its life cycle ena productrsquos carbon footprint consists of the LCA limited tothe emissions that have an eect on climate change eproperty often referred to as carbon footprint is the weightin kilograms or tons of GHG emissions per person productor activity for which an emissions inventory is required [7]
Several authors around the world have reported theadvantages of using recycled materials in the reduction ofGHG In Taiwan LCA in the rehabilitation of pavementsusing recycled materials was evaluated e conventionalmaterials replaced by recycled materials were crushed stone(67) sand (50) and asphalt cement (70) e resultsrevealed GHG reductions of 16 to 23 [8] In a study de-veloped in Hong Kong GHG reductions ranged from 6 to17 in the construction of concrete buildings using variousrecycled materials such as recovered stone aggregates bricksand concrete blocks plastics asphalts and galvanized steelsamong others [9] In Australia a GHG reduction about10 was determined when geopolymers replaced ordinaryportland concrete (OPC) in the manufacture of concrete[10] Recently in the USA Asutosh and Nawari [11] rep-orted that the use of recycled materials in pavement con-struction reduces GHG emissions about 12
In spite of this evidence great care must be taken in thedevelopment of this kind of studies since small variations inthe goals and objectives denition data gathering frominventories and the election of the impact analysis meth-odology may cause important dierences in the environ-mental qualication obtained during the interpretation ofresults phase According to all of the above the main ob-jective of the present work was to evaluate the environmentalsustainability of a concrete produced with both virgin andrecycled aggregates through the comparison of its carbonfootprint expecting that CO2 emissions decrease when theamount of recycled coarse aggregate in the mix increasesduring the concrete manufacturing process
2 Materials and Methods
In the present study the concretersquos carbon footprint in-volved the quantication of the GHG released throughoutthe manufacturing process including material supply eGHGs were mainly carbon dioxide (CO2) methane (CH4)and nitrous oxide (N2O) which have impact on globalwarming In this work the environmental impact was cal-culated from eld data and from the data obtained in dif-ferent inventories following the internationally recognizedstandard ISO 14064-1 [12] In this way it was possible toknow the carbon dioxide equivalent mass (CO2-e) originatedduring the concrete manufacturing process e study wasperformed according to the framework shown in Figure 1
Objectives and scope included both the exact denitionof the system under study and the depth of the study In-ventory analysis consisted in the data collection to quantify
material and energy inputs and outputs of the studied systemImpact and damage assessment was related to the identi-cation characterization and quantication of the eects ofthe studied system on the environment In the interpretationof results phase signicant points were identied based on theoutcomes from the previous phases corroborating theirintegrity sensitivity and coherence sustaining the conclu-sions and recommendations of the study on the base of theinherent limitations of the work
21 Scope and System Limits e analysis was focused onthe aggregate production for the concrete manufacture neand coarse aggregate coming from crushed virgin lime-stone and recycled coarse aggregate obtained from thetrituration and classication of concrete debris Limestone isthe most common in the study region (Yucatan Mexico)Five concrete mixes were produced with a watercementratio (wc) of 05 and other ve mixes with a wc of 07 Fivereplacement rates of virgin coarse aggregate by recycledcoarse aggregate (R) were used 0 25 50 75 and 100OPC was used in all mixtures and its production processwas considered independently from the rest of the materials
e material was collected selectively in CDW landllsleaving it free of undesirable residues such as steel and plasticsamong others CDWcomposition is very diverse from one placeto another and depends on the construction processes availablematerials and population customs e most common com-ponents of CDW are concrete and mortar masonry ceramicbrvbaroors wood plastics and metals Dierent authors in severalparts of the world agree that the rst three predominate whichare the main raw material for recycling processes reachingbetween 30 and 40 of total waste [13 14]
In this research only debris from structural elements suchas slabs beams and columns was selected Subsequentlyreinforcement steel wires ducts and other electric materialwere dismantled and the material was brushed to cleanimpurities such as earth and vegetable remains e extractedrawmaterial was taken to an impact mill plant for grinding sothat coarse recycled aggregate could be obtained In the sameplant the virgin material coming from a bank was crushed toobtain the ne and coarse aggregates and then the tests werecarried out In Tables 1 and 2 aggregate properties andmixture design are indicated
Objectives and scope
Inventory analysis
Impact and damage assessment
Result interpretation
Figure 1 Framework for carbon footprint assessment
2 Advances in Civil Engineering
Figure 2 shows the CO2-e emission system for theproduction of 1m3 of concrete (both regular and recycled)Raw material refers to limestone and water e differencebetween both concrete types is that in order to produce therecycled aggregate mix concrete debris extracted fromCDW is also used
22 Inventory Analysis is phase involved data collectionand calculation procedures to quantify the systemrsquos inputsand outputs Data collection was classified into two levels
221 Level 1 In this level energy consumption and otherresources are obtained from the operating facilitiesrsquo pro-cessing logs which include yields and resource consumptionrates at the time of the facilityrsquos operation activities ey aretypically derived from the use of a fossil fuel (diesel) for theraw material transport In this case it refers to vehicle fuelconsumption for the transportation of the materials as wellas the limestonersquos exploitation rates and volumes use ofexplosives and water that generate CO2-e emissions
222 Level 2 In this level CO2-e emission factors formaterialproduction were determined ey are induced indirectly bythe activity under analysis not emitted in the place where theactivity was carried out since they were derived from sourcesnot directly controlled In this case these were associated withcement production energy consumption and utilization ratesof materials for the manufacture of concrete ey were col-lected from different databases as indicated in Table 3
Table 3 shows an average emission factor of 745 kgCO2-eton for OPC average [15] e value of 612 kg CO2-
eton reported in 2013 by the main cement producer inMexico [19] was rejected because in that report thecompany does not indicate the methodology used for theemission factor calculation and on the contrary it differsmarkedly from what is reported in other countries witha higher degree of industrialization and technologicalprogress where the estimated emission factor ranges from800 to 850 kg CO2-eton of cement as in GermanyFrance Denmark and other European Union countries[20ndash23] Total amount of CO2-em3 emissions of concretecorresponded to the sum of the emissions from cementproduction aggregates water casting and concrete place-mentese components required the use of limestone waterelectricity diesel fuel and explosives e latter refers toamixture of low-density explosive agents and other additionalelements such as fulminant and wicks used during blastingwork
3 Results and Discussion
Carbon footprint assessment for each concrete mixexpressed in kg CO2-em3 is summarized in Table 4 whichincludes total cement aggregates and other nonsignificantemissions such as the use of water and explosive agents
Calculations were made from the following equation
where Q corresponds to the material quantity or input usedand F represents the emission factor for the production of1m3 of concrete Also in Table 4 the results of compressivestrength (Fc) for each concrete mixture expressed in MPahave been included to show their relationship with CO2-eemissions
In the Partial column of Table 2 the sum of emissions isregistered excluding the cement contribution since thismaterial generates most of the total emissions when com-pared to the rest of the elements with more than 80(Figure 3) similar to what was reported by Marincovic et al[24]
On the contrary the influence of fine and coarse ag-gregates has been compared in Figure 4 where it can beappreciated that recycled coarse aggregate has a slight lowercontribution than virgin gravel with a difference of 3
As expected because of the difference in the cementcontent the carbon footprint of the mix with 05 wc was25 higher than that of the mix with 07 wc e carbonfootprint of all the analyzed mixes decreased to a smallextent as the coarse aggregate R increased For the case ofthe concrete with 05 wc the values fluctuated between 347and 351 kg of CO2-em3 slightly lower than that reported byTurner and Collins [10] under similar conditions (354 kg ofCO2-em3 for a 06 wc) and than that reported by Kim et al(356 kg of CO2-em3 for a concrete with compressivestrength of 30MPa) [25]
Since the carbon footprint itself is an intermediate as-sessment point the impacts were converted to damage tohuman health is was determined considering that 1 kgCO2-e represents 21times 10minus7 DALY (disability-adjusted life
year) which expresses the number of years lost as a result oflack of health disability or premature death [26] Applyingthis conversion factor the obtained DALY values rangedfrom 729 to 736times10minus5 (about 385 minutes) for 05 wc andfrom 549 to 556times10minus5 (about 29 minutes) for 07 wc
ese results may seem insignicant at the global level asthey would need to be standardized and weighted consid-ering other impact categories such as eutrophicationacidication and land use change which is beyond the scopeof this research
Finally the construction industry generates a largeamount of waste either by the construction process itself orby demolition in fact it is the largest source of industrial
waste in developed countries which have been estimated ina range of 520 and 760 kgpersonyear without taking intoaccount wars or natural disasters [4] of this large volumeconcrete is the most abundant since it represents 67by weight If we consider an average of 640 kgpersonyearand the Yucatan Peninsula population of 417 million in-habitants by the year 2010 [27] theMexican region in whichmost of the limestone aggregates in the country are pro-duced a total concrete waste is 179 million tons per yearthat is around 744751 cubic meters per year If suchquantity were recycled this would imply that approximately22343 tons of CO2-e would cease to be emitted per year inthis region
Table 3 Inventory of CO2-e energy and materials
Input Factor Unit Context ReferenceCement 0745 kg CO2-ekg Mexico 2004 [15]ExplosivesYield 0465 kg productm3 Mexico 2014 [16]Emission 0440 kg CO2-ekg Australia 2013 [10]
DieselYield 3000 kmL Mexico 2014 [16]Emission 2680 kg CO2-eL Australia 2013 [10]
CoarseYield for normal 1320 m3 stone1000 kg Mexico 2014 [16]Yield for recycled 0002 m3 debriskg Mexico 2014 [16]Emission 0041 kg CO2-ekg Australia 2013 [10]
FineYield 1120 m3 stone1000 kg Mexico 2014 [16]Emission 0014 kg CO2-ekg Australia 2013 [10]
Electricity 0458 kg CO2-eKWH Mexico 2015 [17]Water 0540 KWHm3 Mexico 2011 [18]ConcreteCasting and laying 0012 kg CO2-ekg Australia 2013 [10]
CO2-e
Electricity
Diesel
Transport
ExplosivesCement
Coarse
Fine
Casting and laying
Concrete (1 m3)
Raw material
System boundary
Figure 2 CO2-e emission system for the concrete production
4 Advances in Civil Engineering
4 Conclusions
Specic conclusions of the present work are drawn basedupon the experimental results
(i) It was determined that CO2-e emissions decreaseslightly by increasing the percentage of recycledcoarse aggregates in the concretemixtures indicatingthat the use of this material has little inbrvbaruence on thereduction of the carbon footprint in the concretemanufacturing process
(ii) It was also conrmed that cement is the materialwith the greatest inbrvbaruence on greenhouse gasemissions in the production of concrete
(iii) If we consider the per capita generation average ofconcrete waste from the construction industry andthe population of the region where most of thelimestone aggregates in Mexico are produced therecycling of concrete waste would imply that ap-proximately 22343 tons of CO2-e would cease to beemitted annually in this region
(iv) Regarding the use of recycled aggregates in concreteproduction although the progress has been made inthe study of the physical mechanical and durabilityproperties of the material there is still a large area ofopportunity in the research of the environmentalimpacts involved Future research avenues shouldconsider the contributions of other cementitiousmaterials within a broader LCA framework in-cluding both the use stage and the nal disposal ofbuildings besides the construction stage
Conflicts of Interest
e authors declare that there are no conbrvbaricts of interestregarding the publication of this paper
Acknowledgments
e authors are very grateful to Triturados y Carpetas delSureste S A de C V for their support in the crushing ofstone material and measurement of energy consumption atits industrial plant in Yucatan Mexico
References
[1] R Reham and M Nehdi ldquoCarbon dioxide emissions andclimate change policy implications for cement industryrdquoEnvironmental Science and Policy vol 8 no 2 pp 105ndash1142005
[2] S Talukdar S T Islam and N Banthia ldquoDevelopment ofa lightweight low-carbon footprint concrete containing recy-cled waste materialsrdquo Advances in Civil Engineering vol 2011Article ID 594270 8 pages 2011
[3] L F Jimenez and E I Moreno ldquoDurability indicators in highabsorption recycled aggregate concreterdquo Advances in MaterialsScience and Engineering vol 2015 Article ID 5054238 pages2015
[4] J A Domınguez Lepe E Martınez Lobeck and V VillanuevaCuevas ldquoHormigones reciclados una alternativa sustentabley rentablerdquo Hormigon vol 867 pp 10ndash21 2004
[5] P Van den Heede and N De Belie ldquoEnvironmental impactand life cycle assessment (LCA) of traditional and lsquogreenrsquoconcretes literature review and theoretical calculationsrdquoCement and Concrete Composites vol 34 no 4 pp 431ndash4422012
[6] C Meyer ldquoe greening of the concrete industryrdquo Cementand Concrete Composites vol 31 no 8 pp 601ndash605 2009
[7] T Wiedmann and J Minx ldquoA denition of carbon footprintrdquoin Ecological Economics Research Trends Chapter 1C C Pertsova Ed pp 1ndash11 Nova Science PublishersHauppauge NY USA 2008
[8] C-T Chiu T-H Hsu andW-F Yang ldquoLife cycle assessmenton using recycled materials for rehabilitating asphalt pave-mentsrdquo Resources Conservations and Recycling vol 52 no 3pp 545ndash556 2008
[9] C K Chau W K Hui W Y Ng and G Powell ldquoAssessmentof CO2 emissions reduction in high-rise concrete officebuildings using different material use optionsrdquo ResourcesConservations and Recycling vol 61 pp 22ndash34 2012
[10] L K Turner and F G Collins ldquoCarbon dioxide equivalent(CO2-e) emissions a comparison between geopolymer andOPC cement concreterdquo Construction and Building Materialsvol 43 pp 125ndash130 2013
[11] A T Asutosh and N O Nawari ldquoIntegration of recycledindustrial wastes into pavement design and construction fora sustainable futurerdquo Journal of Sustainable Developmentvol 10 no 1 pp 9ndash23 2017
[12] International Organization for Standardization ISO 14064-1International Organization for Standardization GenevaSwitzerland 2006
[13] S C Angulo L F R Miranda and V M John ldquoConstructionand demolition waste its variability and recycling in Brazilrdquoin Proceedings of the International Conference on SustainableBuilding Oslo Norway April 2002
[14] N D Oikonomou ldquoRecycled concrete aggregatesrdquoCement and Concrete Composites vol 27 no 2 pp 315ndash318 2005
[15] Instituto Nacional de Ecologıa Inventario Nacional de Emi-siones de Gases de Efecto Invernadero 1990-2002 InstitutoNacional de Ecologıa Mexico 2004
[16] L F Jimenez Torrez Durabilidad del concreto con agregadoreciclado de alta absorcion PhD dissertation UniversidadAutonoma de Yucatan Merida Mexico 2015
[17] Secretarıa del Medio Ambiente y Recursos Naturales RegistroNacional de Emisiones Secretarıa delMedio Ambiente y RecursosNaturales Mexico 2015
[18] Comision Nacional para el Uso Eficiente de la EnergıaEstudio Integral de Sistemas de Bombeo de Agua PotableMunicipal Comision Nacional para el Uso Eficiente de laEnergıa Mexico 2011
[19] CEMEX SAB de CV Informe de Desarrollo SustentableCEMEX San Pedro Garza Garcıa Mexico 2013
[20] Oko-Institut ldquoApproximated EU GHG inventory proxyGHG emission estimates for 2013rdquo EEA Technical Report 16Oko-Institut Germany 2013
[21] Association Technique des Liants Hydrauliques Environ-mental Inventory of French Cement Production AssociationTechnique des Liants Hydrauliques Paris France 2012
[22] J S Damtoft J Lukasik D Hertfort D Sorrentino andE M Gartner ldquoSustainable development and climate changeinitiativesrdquo Cement and Concrete Research vol 38 no 2pp 115ndash127 2008
[23] A Josa A Aguado A Heino E Byars and A CardimldquoComparative analysis of available life cycle inventories ofcement in the EUrdquo Cement and Concrete Research vol 34no 8 pp 1313ndash1320 2004
[24] S Marincovic V Radonjanin M Malesev and I IgnjatovicldquoComparative environmental assessment of natural andrecycled aggregate concreterdquo Waste Management vol 30no 11 pp 2255ndash2264 2010
[25] T H Kim C U Chae G H Kim and H J Jang ldquoAnalysis ofCO2 emission characteristics of concrete used at constructionsitesrdquo Sustainability vol 8 no 4 p 348 2016
[26] M Goedkoop and R Spriensma 9e Eco-Indicator 99 ADamage Oriented Method for Life Cycle Impact Assessment
Methodology Report PRe Consultants Amersfoort Nether-lands 3rd edition 2011
[27] Mexicorsquos National Council of Population CONAPO De-mographic Dynamics 1990ndash2010 and Population Projections2010ndash2030 Mexicorsquos National Council of Population Mexico2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Navigation and Observation
International Journal of
Hindawi
wwwhindawicom Volume 2018
Advances in
Multimedia
Submit your manuscripts atwwwhindawicom
Figure 2 shows the CO2-e emission system for theproduction of 1m3 of concrete (both regular and recycled)Raw material refers to limestone and water e differencebetween both concrete types is that in order to produce therecycled aggregate mix concrete debris extracted fromCDW is also used
22 Inventory Analysis is phase involved data collectionand calculation procedures to quantify the systemrsquos inputsand outputs Data collection was classified into two levels
221 Level 1 In this level energy consumption and otherresources are obtained from the operating facilitiesrsquo pro-cessing logs which include yields and resource consumptionrates at the time of the facilityrsquos operation activities ey aretypically derived from the use of a fossil fuel (diesel) for theraw material transport In this case it refers to vehicle fuelconsumption for the transportation of the materials as wellas the limestonersquos exploitation rates and volumes use ofexplosives and water that generate CO2-e emissions
222 Level 2 In this level CO2-e emission factors formaterialproduction were determined ey are induced indirectly bythe activity under analysis not emitted in the place where theactivity was carried out since they were derived from sourcesnot directly controlled In this case these were associated withcement production energy consumption and utilization ratesof materials for the manufacture of concrete ey were col-lected from different databases as indicated in Table 3
Table 3 shows an average emission factor of 745 kgCO2-eton for OPC average [15] e value of 612 kg CO2-
eton reported in 2013 by the main cement producer inMexico [19] was rejected because in that report thecompany does not indicate the methodology used for theemission factor calculation and on the contrary it differsmarkedly from what is reported in other countries witha higher degree of industrialization and technologicalprogress where the estimated emission factor ranges from800 to 850 kg CO2-eton of cement as in GermanyFrance Denmark and other European Union countries[20ndash23] Total amount of CO2-em3 emissions of concretecorresponded to the sum of the emissions from cementproduction aggregates water casting and concrete place-mentese components required the use of limestone waterelectricity diesel fuel and explosives e latter refers toamixture of low-density explosive agents and other additionalelements such as fulminant and wicks used during blastingwork
3 Results and Discussion
Carbon footprint assessment for each concrete mixexpressed in kg CO2-em3 is summarized in Table 4 whichincludes total cement aggregates and other nonsignificantemissions such as the use of water and explosive agents
Calculations were made from the following equation
where Q corresponds to the material quantity or input usedand F represents the emission factor for the production of1m3 of concrete Also in Table 4 the results of compressivestrength (Fc) for each concrete mixture expressed in MPahave been included to show their relationship with CO2-eemissions
In the Partial column of Table 2 the sum of emissions isregistered excluding the cement contribution since thismaterial generates most of the total emissions when com-pared to the rest of the elements with more than 80(Figure 3) similar to what was reported by Marincovic et al[24]
On the contrary the influence of fine and coarse ag-gregates has been compared in Figure 4 where it can beappreciated that recycled coarse aggregate has a slight lowercontribution than virgin gravel with a difference of 3
As expected because of the difference in the cementcontent the carbon footprint of the mix with 05 wc was25 higher than that of the mix with 07 wc e carbonfootprint of all the analyzed mixes decreased to a smallextent as the coarse aggregate R increased For the case ofthe concrete with 05 wc the values fluctuated between 347and 351 kg of CO2-em3 slightly lower than that reported byTurner and Collins [10] under similar conditions (354 kg ofCO2-em3 for a 06 wc) and than that reported by Kim et al(356 kg of CO2-em3 for a concrete with compressivestrength of 30MPa) [25]
Since the carbon footprint itself is an intermediate as-sessment point the impacts were converted to damage tohuman health is was determined considering that 1 kgCO2-e represents 21times 10minus7 DALY (disability-adjusted life
year) which expresses the number of years lost as a result oflack of health disability or premature death [26] Applyingthis conversion factor the obtained DALY values rangedfrom 729 to 736times10minus5 (about 385 minutes) for 05 wc andfrom 549 to 556times10minus5 (about 29 minutes) for 07 wc
ese results may seem insignicant at the global level asthey would need to be standardized and weighted consid-ering other impact categories such as eutrophicationacidication and land use change which is beyond the scopeof this research
Finally the construction industry generates a largeamount of waste either by the construction process itself orby demolition in fact it is the largest source of industrial
waste in developed countries which have been estimated ina range of 520 and 760 kgpersonyear without taking intoaccount wars or natural disasters [4] of this large volumeconcrete is the most abundant since it represents 67by weight If we consider an average of 640 kgpersonyearand the Yucatan Peninsula population of 417 million in-habitants by the year 2010 [27] theMexican region in whichmost of the limestone aggregates in the country are pro-duced a total concrete waste is 179 million tons per yearthat is around 744751 cubic meters per year If suchquantity were recycled this would imply that approximately22343 tons of CO2-e would cease to be emitted per year inthis region
Table 3 Inventory of CO2-e energy and materials
Input Factor Unit Context ReferenceCement 0745 kg CO2-ekg Mexico 2004 [15]ExplosivesYield 0465 kg productm3 Mexico 2014 [16]Emission 0440 kg CO2-ekg Australia 2013 [10]
DieselYield 3000 kmL Mexico 2014 [16]Emission 2680 kg CO2-eL Australia 2013 [10]
CoarseYield for normal 1320 m3 stone1000 kg Mexico 2014 [16]Yield for recycled 0002 m3 debriskg Mexico 2014 [16]Emission 0041 kg CO2-ekg Australia 2013 [10]
FineYield 1120 m3 stone1000 kg Mexico 2014 [16]Emission 0014 kg CO2-ekg Australia 2013 [10]
Electricity 0458 kg CO2-eKWH Mexico 2015 [17]Water 0540 KWHm3 Mexico 2011 [18]ConcreteCasting and laying 0012 kg CO2-ekg Australia 2013 [10]
CO2-e
Electricity
Diesel
Transport
ExplosivesCement
Coarse
Fine
Casting and laying
Concrete (1 m3)
Raw material
System boundary
Figure 2 CO2-e emission system for the concrete production
4 Advances in Civil Engineering
4 Conclusions
Specic conclusions of the present work are drawn basedupon the experimental results
(i) It was determined that CO2-e emissions decreaseslightly by increasing the percentage of recycledcoarse aggregates in the concretemixtures indicatingthat the use of this material has little inbrvbaruence on thereduction of the carbon footprint in the concretemanufacturing process
(ii) It was also conrmed that cement is the materialwith the greatest inbrvbaruence on greenhouse gasemissions in the production of concrete
(iii) If we consider the per capita generation average ofconcrete waste from the construction industry andthe population of the region where most of thelimestone aggregates in Mexico are produced therecycling of concrete waste would imply that ap-proximately 22343 tons of CO2-e would cease to beemitted annually in this region
(iv) Regarding the use of recycled aggregates in concreteproduction although the progress has been made inthe study of the physical mechanical and durabilityproperties of the material there is still a large area ofopportunity in the research of the environmentalimpacts involved Future research avenues shouldconsider the contributions of other cementitiousmaterials within a broader LCA framework in-cluding both the use stage and the nal disposal ofbuildings besides the construction stage
Conflicts of Interest
e authors declare that there are no conbrvbaricts of interestregarding the publication of this paper
Acknowledgments
e authors are very grateful to Triturados y Carpetas delSureste S A de C V for their support in the crushing ofstone material and measurement of energy consumption atits industrial plant in Yucatan Mexico
References
[1] R Reham and M Nehdi ldquoCarbon dioxide emissions andclimate change policy implications for cement industryrdquoEnvironmental Science and Policy vol 8 no 2 pp 105ndash1142005
[2] S Talukdar S T Islam and N Banthia ldquoDevelopment ofa lightweight low-carbon footprint concrete containing recy-cled waste materialsrdquo Advances in Civil Engineering vol 2011Article ID 594270 8 pages 2011
[3] L F Jimenez and E I Moreno ldquoDurability indicators in highabsorption recycled aggregate concreterdquo Advances in MaterialsScience and Engineering vol 2015 Article ID 5054238 pages2015
[4] J A Domınguez Lepe E Martınez Lobeck and V VillanuevaCuevas ldquoHormigones reciclados una alternativa sustentabley rentablerdquo Hormigon vol 867 pp 10ndash21 2004
[5] P Van den Heede and N De Belie ldquoEnvironmental impactand life cycle assessment (LCA) of traditional and lsquogreenrsquoconcretes literature review and theoretical calculationsrdquoCement and Concrete Composites vol 34 no 4 pp 431ndash4422012
[6] C Meyer ldquoe greening of the concrete industryrdquo Cementand Concrete Composites vol 31 no 8 pp 601ndash605 2009
[7] T Wiedmann and J Minx ldquoA denition of carbon footprintrdquoin Ecological Economics Research Trends Chapter 1C C Pertsova Ed pp 1ndash11 Nova Science PublishersHauppauge NY USA 2008
[8] C-T Chiu T-H Hsu andW-F Yang ldquoLife cycle assessmenton using recycled materials for rehabilitating asphalt pave-mentsrdquo Resources Conservations and Recycling vol 52 no 3pp 545ndash556 2008
[9] C K Chau W K Hui W Y Ng and G Powell ldquoAssessmentof CO2 emissions reduction in high-rise concrete officebuildings using different material use optionsrdquo ResourcesConservations and Recycling vol 61 pp 22ndash34 2012
[10] L K Turner and F G Collins ldquoCarbon dioxide equivalent(CO2-e) emissions a comparison between geopolymer andOPC cement concreterdquo Construction and Building Materialsvol 43 pp 125ndash130 2013
[11] A T Asutosh and N O Nawari ldquoIntegration of recycledindustrial wastes into pavement design and construction fora sustainable futurerdquo Journal of Sustainable Developmentvol 10 no 1 pp 9ndash23 2017
[12] International Organization for Standardization ISO 14064-1International Organization for Standardization GenevaSwitzerland 2006
[13] S C Angulo L F R Miranda and V M John ldquoConstructionand demolition waste its variability and recycling in Brazilrdquoin Proceedings of the International Conference on SustainableBuilding Oslo Norway April 2002
[14] N D Oikonomou ldquoRecycled concrete aggregatesrdquoCement and Concrete Composites vol 27 no 2 pp 315ndash318 2005
[15] Instituto Nacional de Ecologıa Inventario Nacional de Emi-siones de Gases de Efecto Invernadero 1990-2002 InstitutoNacional de Ecologıa Mexico 2004
[16] L F Jimenez Torrez Durabilidad del concreto con agregadoreciclado de alta absorcion PhD dissertation UniversidadAutonoma de Yucatan Merida Mexico 2015
[17] Secretarıa del Medio Ambiente y Recursos Naturales RegistroNacional de Emisiones Secretarıa delMedio Ambiente y RecursosNaturales Mexico 2015
[18] Comision Nacional para el Uso Eficiente de la EnergıaEstudio Integral de Sistemas de Bombeo de Agua PotableMunicipal Comision Nacional para el Uso Eficiente de laEnergıa Mexico 2011
[19] CEMEX SAB de CV Informe de Desarrollo SustentableCEMEX San Pedro Garza Garcıa Mexico 2013
[20] Oko-Institut ldquoApproximated EU GHG inventory proxyGHG emission estimates for 2013rdquo EEA Technical Report 16Oko-Institut Germany 2013
[21] Association Technique des Liants Hydrauliques Environ-mental Inventory of French Cement Production AssociationTechnique des Liants Hydrauliques Paris France 2012
[22] J S Damtoft J Lukasik D Hertfort D Sorrentino andE M Gartner ldquoSustainable development and climate changeinitiativesrdquo Cement and Concrete Research vol 38 no 2pp 115ndash127 2008
[23] A Josa A Aguado A Heino E Byars and A CardimldquoComparative analysis of available life cycle inventories ofcement in the EUrdquo Cement and Concrete Research vol 34no 8 pp 1313ndash1320 2004
[24] S Marincovic V Radonjanin M Malesev and I IgnjatovicldquoComparative environmental assessment of natural andrecycled aggregate concreterdquo Waste Management vol 30no 11 pp 2255ndash2264 2010
[25] T H Kim C U Chae G H Kim and H J Jang ldquoAnalysis ofCO2 emission characteristics of concrete used at constructionsitesrdquo Sustainability vol 8 no 4 p 348 2016
[26] M Goedkoop and R Spriensma 9e Eco-Indicator 99 ADamage Oriented Method for Life Cycle Impact Assessment
Methodology Report PRe Consultants Amersfoort Nether-lands 3rd edition 2011
[27] Mexicorsquos National Council of Population CONAPO De-mographic Dynamics 1990ndash2010 and Population Projections2010ndash2030 Mexicorsquos National Council of Population Mexico2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Navigation and Observation
International Journal of
Hindawi
wwwhindawicom Volume 2018
Advances in
Multimedia
Submit your manuscripts atwwwhindawicom
year) which expresses the number of years lost as a result oflack of health disability or premature death [26] Applyingthis conversion factor the obtained DALY values rangedfrom 729 to 736times10minus5 (about 385 minutes) for 05 wc andfrom 549 to 556times10minus5 (about 29 minutes) for 07 wc
ese results may seem insignicant at the global level asthey would need to be standardized and weighted consid-ering other impact categories such as eutrophicationacidication and land use change which is beyond the scopeof this research
Finally the construction industry generates a largeamount of waste either by the construction process itself orby demolition in fact it is the largest source of industrial
waste in developed countries which have been estimated ina range of 520 and 760 kgpersonyear without taking intoaccount wars or natural disasters [4] of this large volumeconcrete is the most abundant since it represents 67by weight If we consider an average of 640 kgpersonyearand the Yucatan Peninsula population of 417 million in-habitants by the year 2010 [27] theMexican region in whichmost of the limestone aggregates in the country are pro-duced a total concrete waste is 179 million tons per yearthat is around 744751 cubic meters per year If suchquantity were recycled this would imply that approximately22343 tons of CO2-e would cease to be emitted per year inthis region
Table 3 Inventory of CO2-e energy and materials
Input Factor Unit Context ReferenceCement 0745 kg CO2-ekg Mexico 2004 [15]ExplosivesYield 0465 kg productm3 Mexico 2014 [16]Emission 0440 kg CO2-ekg Australia 2013 [10]
DieselYield 3000 kmL Mexico 2014 [16]Emission 2680 kg CO2-eL Australia 2013 [10]
CoarseYield for normal 1320 m3 stone1000 kg Mexico 2014 [16]Yield for recycled 0002 m3 debriskg Mexico 2014 [16]Emission 0041 kg CO2-ekg Australia 2013 [10]
FineYield 1120 m3 stone1000 kg Mexico 2014 [16]Emission 0014 kg CO2-ekg Australia 2013 [10]
Electricity 0458 kg CO2-eKWH Mexico 2015 [17]Water 0540 KWHm3 Mexico 2011 [18]ConcreteCasting and laying 0012 kg CO2-ekg Australia 2013 [10]
CO2-e
Electricity
Diesel
Transport
ExplosivesCement
Coarse
Fine
Casting and laying
Concrete (1 m3)
Raw material
System boundary
Figure 2 CO2-e emission system for the concrete production
4 Advances in Civil Engineering
4 Conclusions
Specic conclusions of the present work are drawn basedupon the experimental results
(i) It was determined that CO2-e emissions decreaseslightly by increasing the percentage of recycledcoarse aggregates in the concretemixtures indicatingthat the use of this material has little inbrvbaruence on thereduction of the carbon footprint in the concretemanufacturing process
(ii) It was also conrmed that cement is the materialwith the greatest inbrvbaruence on greenhouse gasemissions in the production of concrete
(iii) If we consider the per capita generation average ofconcrete waste from the construction industry andthe population of the region where most of thelimestone aggregates in Mexico are produced therecycling of concrete waste would imply that ap-proximately 22343 tons of CO2-e would cease to beemitted annually in this region
(iv) Regarding the use of recycled aggregates in concreteproduction although the progress has been made inthe study of the physical mechanical and durabilityproperties of the material there is still a large area ofopportunity in the research of the environmentalimpacts involved Future research avenues shouldconsider the contributions of other cementitiousmaterials within a broader LCA framework in-cluding both the use stage and the nal disposal ofbuildings besides the construction stage
Conflicts of Interest
e authors declare that there are no conbrvbaricts of interestregarding the publication of this paper
Acknowledgments
e authors are very grateful to Triturados y Carpetas delSureste S A de C V for their support in the crushing ofstone material and measurement of energy consumption atits industrial plant in Yucatan Mexico
References
[1] R Reham and M Nehdi ldquoCarbon dioxide emissions andclimate change policy implications for cement industryrdquoEnvironmental Science and Policy vol 8 no 2 pp 105ndash1142005
[2] S Talukdar S T Islam and N Banthia ldquoDevelopment ofa lightweight low-carbon footprint concrete containing recy-cled waste materialsrdquo Advances in Civil Engineering vol 2011Article ID 594270 8 pages 2011
[3] L F Jimenez and E I Moreno ldquoDurability indicators in highabsorption recycled aggregate concreterdquo Advances in MaterialsScience and Engineering vol 2015 Article ID 5054238 pages2015
[4] J A Domınguez Lepe E Martınez Lobeck and V VillanuevaCuevas ldquoHormigones reciclados una alternativa sustentabley rentablerdquo Hormigon vol 867 pp 10ndash21 2004
[5] P Van den Heede and N De Belie ldquoEnvironmental impactand life cycle assessment (LCA) of traditional and lsquogreenrsquoconcretes literature review and theoretical calculationsrdquoCement and Concrete Composites vol 34 no 4 pp 431ndash4422012
[6] C Meyer ldquoe greening of the concrete industryrdquo Cementand Concrete Composites vol 31 no 8 pp 601ndash605 2009
[7] T Wiedmann and J Minx ldquoA denition of carbon footprintrdquoin Ecological Economics Research Trends Chapter 1C C Pertsova Ed pp 1ndash11 Nova Science PublishersHauppauge NY USA 2008
[8] C-T Chiu T-H Hsu andW-F Yang ldquoLife cycle assessmenton using recycled materials for rehabilitating asphalt pave-mentsrdquo Resources Conservations and Recycling vol 52 no 3pp 545ndash556 2008
[9] C K Chau W K Hui W Y Ng and G Powell ldquoAssessmentof CO2 emissions reduction in high-rise concrete officebuildings using different material use optionsrdquo ResourcesConservations and Recycling vol 61 pp 22ndash34 2012
[10] L K Turner and F G Collins ldquoCarbon dioxide equivalent(CO2-e) emissions a comparison between geopolymer andOPC cement concreterdquo Construction and Building Materialsvol 43 pp 125ndash130 2013
[11] A T Asutosh and N O Nawari ldquoIntegration of recycledindustrial wastes into pavement design and construction fora sustainable futurerdquo Journal of Sustainable Developmentvol 10 no 1 pp 9ndash23 2017
[12] International Organization for Standardization ISO 14064-1International Organization for Standardization GenevaSwitzerland 2006
[13] S C Angulo L F R Miranda and V M John ldquoConstructionand demolition waste its variability and recycling in Brazilrdquoin Proceedings of the International Conference on SustainableBuilding Oslo Norway April 2002
[14] N D Oikonomou ldquoRecycled concrete aggregatesrdquoCement and Concrete Composites vol 27 no 2 pp 315ndash318 2005
[15] Instituto Nacional de Ecologıa Inventario Nacional de Emi-siones de Gases de Efecto Invernadero 1990-2002 InstitutoNacional de Ecologıa Mexico 2004
[16] L F Jimenez Torrez Durabilidad del concreto con agregadoreciclado de alta absorcion PhD dissertation UniversidadAutonoma de Yucatan Merida Mexico 2015
[17] Secretarıa del Medio Ambiente y Recursos Naturales RegistroNacional de Emisiones Secretarıa delMedio Ambiente y RecursosNaturales Mexico 2015
[18] Comision Nacional para el Uso Eficiente de la EnergıaEstudio Integral de Sistemas de Bombeo de Agua PotableMunicipal Comision Nacional para el Uso Eficiente de laEnergıa Mexico 2011
[19] CEMEX SAB de CV Informe de Desarrollo SustentableCEMEX San Pedro Garza Garcıa Mexico 2013
[20] Oko-Institut ldquoApproximated EU GHG inventory proxyGHG emission estimates for 2013rdquo EEA Technical Report 16Oko-Institut Germany 2013
[21] Association Technique des Liants Hydrauliques Environ-mental Inventory of French Cement Production AssociationTechnique des Liants Hydrauliques Paris France 2012
[22] J S Damtoft J Lukasik D Hertfort D Sorrentino andE M Gartner ldquoSustainable development and climate changeinitiativesrdquo Cement and Concrete Research vol 38 no 2pp 115ndash127 2008
[23] A Josa A Aguado A Heino E Byars and A CardimldquoComparative analysis of available life cycle inventories ofcement in the EUrdquo Cement and Concrete Research vol 34no 8 pp 1313ndash1320 2004
[24] S Marincovic V Radonjanin M Malesev and I IgnjatovicldquoComparative environmental assessment of natural andrecycled aggregate concreterdquo Waste Management vol 30no 11 pp 2255ndash2264 2010
[25] T H Kim C U Chae G H Kim and H J Jang ldquoAnalysis ofCO2 emission characteristics of concrete used at constructionsitesrdquo Sustainability vol 8 no 4 p 348 2016
[26] M Goedkoop and R Spriensma 9e Eco-Indicator 99 ADamage Oriented Method for Life Cycle Impact Assessment
Methodology Report PRe Consultants Amersfoort Nether-lands 3rd edition 2011
[27] Mexicorsquos National Council of Population CONAPO De-mographic Dynamics 1990ndash2010 and Population Projections2010ndash2030 Mexicorsquos National Council of Population Mexico2014
Chemical EngineeringInternational Journal of Antennas and
Propagation
International Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Navigation and Observation
International Journal of
Hindawi
wwwhindawicom Volume 2018
Advances in
Multimedia
Submit your manuscripts atwwwhindawicom
4 Conclusions
Specic conclusions of the present work are drawn basedupon the experimental results
(i) It was determined that CO2-e emissions decreaseslightly by increasing the percentage of recycledcoarse aggregates in the concretemixtures indicatingthat the use of this material has little inbrvbaruence on thereduction of the carbon footprint in the concretemanufacturing process
(ii) It was also conrmed that cement is the materialwith the greatest inbrvbaruence on greenhouse gasemissions in the production of concrete
(iii) If we consider the per capita generation average ofconcrete waste from the construction industry andthe population of the region where most of thelimestone aggregates in Mexico are produced therecycling of concrete waste would imply that ap-proximately 22343 tons of CO2-e would cease to beemitted annually in this region
(iv) Regarding the use of recycled aggregates in concreteproduction although the progress has been made inthe study of the physical mechanical and durabilityproperties of the material there is still a large area ofopportunity in the research of the environmentalimpacts involved Future research avenues shouldconsider the contributions of other cementitiousmaterials within a broader LCA framework in-cluding both the use stage and the nal disposal ofbuildings besides the construction stage
Conflicts of Interest
e authors declare that there are no conbrvbaricts of interestregarding the publication of this paper
Acknowledgments
e authors are very grateful to Triturados y Carpetas delSureste S A de C V for their support in the crushing ofstone material and measurement of energy consumption atits industrial plant in Yucatan Mexico
References
[1] R Reham and M Nehdi ldquoCarbon dioxide emissions andclimate change policy implications for cement industryrdquoEnvironmental Science and Policy vol 8 no 2 pp 105ndash1142005
[2] S Talukdar S T Islam and N Banthia ldquoDevelopment ofa lightweight low-carbon footprint concrete containing recy-cled waste materialsrdquo Advances in Civil Engineering vol 2011Article ID 594270 8 pages 2011
[3] L F Jimenez and E I Moreno ldquoDurability indicators in highabsorption recycled aggregate concreterdquo Advances in MaterialsScience and Engineering vol 2015 Article ID 5054238 pages2015
[4] J A Domınguez Lepe E Martınez Lobeck and V VillanuevaCuevas ldquoHormigones reciclados una alternativa sustentabley rentablerdquo Hormigon vol 867 pp 10ndash21 2004
[5] P Van den Heede and N De Belie ldquoEnvironmental impactand life cycle assessment (LCA) of traditional and lsquogreenrsquoconcretes literature review and theoretical calculationsrdquoCement and Concrete Composites vol 34 no 4 pp 431ndash4422012
[6] C Meyer ldquoe greening of the concrete industryrdquo Cementand Concrete Composites vol 31 no 8 pp 601ndash605 2009
[7] T Wiedmann and J Minx ldquoA denition of carbon footprintrdquoin Ecological Economics Research Trends Chapter 1C C Pertsova Ed pp 1ndash11 Nova Science PublishersHauppauge NY USA 2008
[8] C-T Chiu T-H Hsu andW-F Yang ldquoLife cycle assessmenton using recycled materials for rehabilitating asphalt pave-mentsrdquo Resources Conservations and Recycling vol 52 no 3pp 545ndash556 2008
[9] C K Chau W K Hui W Y Ng and G Powell ldquoAssessmentof CO2 emissions reduction in high-rise concrete officebuildings using different material use optionsrdquo ResourcesConservations and Recycling vol 61 pp 22ndash34 2012
[10] L K Turner and F G Collins ldquoCarbon dioxide equivalent(CO2-e) emissions a comparison between geopolymer andOPC cement concreterdquo Construction and Building Materialsvol 43 pp 125ndash130 2013
[11] A T Asutosh and N O Nawari ldquoIntegration of recycledindustrial wastes into pavement design and construction fora sustainable futurerdquo Journal of Sustainable Developmentvol 10 no 1 pp 9ndash23 2017
[12] International Organization for Standardization ISO 14064-1International Organization for Standardization GenevaSwitzerland 2006
[13] S C Angulo L F R Miranda and V M John ldquoConstructionand demolition waste its variability and recycling in Brazilrdquoin Proceedings of the International Conference on SustainableBuilding Oslo Norway April 2002
[14] N D Oikonomou ldquoRecycled concrete aggregatesrdquoCement and Concrete Composites vol 27 no 2 pp 315ndash318 2005
[15] Instituto Nacional de Ecologıa Inventario Nacional de Emi-siones de Gases de Efecto Invernadero 1990-2002 InstitutoNacional de Ecologıa Mexico 2004
[16] L F Jimenez Torrez Durabilidad del concreto con agregadoreciclado de alta absorcion PhD dissertation UniversidadAutonoma de Yucatan Merida Mexico 2015
[17] Secretarıa del Medio Ambiente y Recursos Naturales RegistroNacional de Emisiones Secretarıa delMedio Ambiente y RecursosNaturales Mexico 2015
[18] Comision Nacional para el Uso Eficiente de la EnergıaEstudio Integral de Sistemas de Bombeo de Agua PotableMunicipal Comision Nacional para el Uso Eficiente de laEnergıa Mexico 2011
[19] CEMEX SAB de CV Informe de Desarrollo SustentableCEMEX San Pedro Garza Garcıa Mexico 2013
[20] Oko-Institut ldquoApproximated EU GHG inventory proxyGHG emission estimates for 2013rdquo EEA Technical Report 16Oko-Institut Germany 2013
[21] Association Technique des Liants Hydrauliques Environ-mental Inventory of French Cement Production AssociationTechnique des Liants Hydrauliques Paris France 2012
[22] J S Damtoft J Lukasik D Hertfort D Sorrentino andE M Gartner ldquoSustainable development and climate changeinitiativesrdquo Cement and Concrete Research vol 38 no 2pp 115ndash127 2008
[23] A Josa A Aguado A Heino E Byars and A CardimldquoComparative analysis of available life cycle inventories ofcement in the EUrdquo Cement and Concrete Research vol 34no 8 pp 1313ndash1320 2004
[24] S Marincovic V Radonjanin M Malesev and I IgnjatovicldquoComparative environmental assessment of natural andrecycled aggregate concreterdquo Waste Management vol 30no 11 pp 2255ndash2264 2010
[25] T H Kim C U Chae G H Kim and H J Jang ldquoAnalysis ofCO2 emission characteristics of concrete used at constructionsitesrdquo Sustainability vol 8 no 4 p 348 2016
[26] M Goedkoop and R Spriensma 9e Eco-Indicator 99 ADamage Oriented Method for Life Cycle Impact Assessment
Methodology Report PRe Consultants Amersfoort Nether-lands 3rd edition 2011
[27] Mexicorsquos National Council of Population CONAPO De-mographic Dynamics 1990ndash2010 and Population Projections2010ndash2030 Mexicorsquos National Council of Population Mexico2014
Chemical EngineeringInternational Journal of Antennas and
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International Journal of
Hindawiwwwhindawicom Volume 2018
Hindawiwwwhindawicom Volume 2018
Navigation and Observation
International Journal of
Hindawi
wwwhindawicom Volume 2018
Advances in
Multimedia
Submit your manuscripts atwwwhindawicom
[8] C-T Chiu T-H Hsu andW-F Yang ldquoLife cycle assessmenton using recycled materials for rehabilitating asphalt pave-mentsrdquo Resources Conservations and Recycling vol 52 no 3pp 545ndash556 2008
[9] C K Chau W K Hui W Y Ng and G Powell ldquoAssessmentof CO2 emissions reduction in high-rise concrete officebuildings using different material use optionsrdquo ResourcesConservations and Recycling vol 61 pp 22ndash34 2012
[10] L K Turner and F G Collins ldquoCarbon dioxide equivalent(CO2-e) emissions a comparison between geopolymer andOPC cement concreterdquo Construction and Building Materialsvol 43 pp 125ndash130 2013
[11] A T Asutosh and N O Nawari ldquoIntegration of recycledindustrial wastes into pavement design and construction fora sustainable futurerdquo Journal of Sustainable Developmentvol 10 no 1 pp 9ndash23 2017
[12] International Organization for Standardization ISO 14064-1International Organization for Standardization GenevaSwitzerland 2006
[13] S C Angulo L F R Miranda and V M John ldquoConstructionand demolition waste its variability and recycling in Brazilrdquoin Proceedings of the International Conference on SustainableBuilding Oslo Norway April 2002
[14] N D Oikonomou ldquoRecycled concrete aggregatesrdquoCement and Concrete Composites vol 27 no 2 pp 315ndash318 2005
[15] Instituto Nacional de Ecologıa Inventario Nacional de Emi-siones de Gases de Efecto Invernadero 1990-2002 InstitutoNacional de Ecologıa Mexico 2004
[16] L F Jimenez Torrez Durabilidad del concreto con agregadoreciclado de alta absorcion PhD dissertation UniversidadAutonoma de Yucatan Merida Mexico 2015
[17] Secretarıa del Medio Ambiente y Recursos Naturales RegistroNacional de Emisiones Secretarıa delMedio Ambiente y RecursosNaturales Mexico 2015
[18] Comision Nacional para el Uso Eficiente de la EnergıaEstudio Integral de Sistemas de Bombeo de Agua PotableMunicipal Comision Nacional para el Uso Eficiente de laEnergıa Mexico 2011
[19] CEMEX SAB de CV Informe de Desarrollo SustentableCEMEX San Pedro Garza Garcıa Mexico 2013
[20] Oko-Institut ldquoApproximated EU GHG inventory proxyGHG emission estimates for 2013rdquo EEA Technical Report 16Oko-Institut Germany 2013
[21] Association Technique des Liants Hydrauliques Environ-mental Inventory of French Cement Production AssociationTechnique des Liants Hydrauliques Paris France 2012
[22] J S Damtoft J Lukasik D Hertfort D Sorrentino andE M Gartner ldquoSustainable development and climate changeinitiativesrdquo Cement and Concrete Research vol 38 no 2pp 115ndash127 2008
[23] A Josa A Aguado A Heino E Byars and A CardimldquoComparative analysis of available life cycle inventories ofcement in the EUrdquo Cement and Concrete Research vol 34no 8 pp 1313ndash1320 2004
[24] S Marincovic V Radonjanin M Malesev and I IgnjatovicldquoComparative environmental assessment of natural andrecycled aggregate concreterdquo Waste Management vol 30no 11 pp 2255ndash2264 2010
[25] T H Kim C U Chae G H Kim and H J Jang ldquoAnalysis ofCO2 emission characteristics of concrete used at constructionsitesrdquo Sustainability vol 8 no 4 p 348 2016
[26] M Goedkoop and R Spriensma 9e Eco-Indicator 99 ADamage Oriented Method for Life Cycle Impact Assessment
Methodology Report PRe Consultants Amersfoort Nether-lands 3rd edition 2011
[27] Mexicorsquos National Council of Population CONAPO De-mographic Dynamics 1990ndash2010 and Population Projections2010ndash2030 Mexicorsquos National Council of Population Mexico2014
