https://doi.org/10.14311/APP.2022.33.0020 Acta Polytechnica CTU Proceedings 33:20–26, 2022 © 2022 The Author(s). Licensed under a CC-BY 4.0 licence Published by the Czech Technical University in Prague USING AN ANALYSIS OF CONCRETE AND CEMENT EPD: VERIFICATION, SELECTION, ASSESSMENT, BENCHMARKING AND TARGET SETTING Jane Anderson∗, Alice Moncaster Open University, Walton Hall, Milton Keynes, Keynes MK7 6AA, UK ∗ corresponding author: jane.anderson@open.ac.uk Abstract. The carbon embodied in buildings is an important proportion of our emissions and needs to be radically reduced in order to support climate change mitigation. The highest proportion of embodied carbon is usually emitted during the product stage, and within the structural elements. Therefore, reducing the carbon embodied in the structural materials is likely to have a major impact. In most buildings, the majority of embodied carbon comes from steel and concrete. But although there are now hundreds of registered Environmental Product Declarations (EPD) for cements and concretes, there has been very limited independent published information comparing the embodied carbon of different concrete mixes and raw materials. This lack of comparative data limits the potential to make appropriate decisions at early design stages leading to low carbon buildings. The authors have recently conducted a review of verified EPD for concrete mixes and for concrete’s key constituents, including cement, identifying the range of carbon coefficients. This paper provides guidance on making use of the coefficient ranges provided in that research: to support the verification of EPD for concrete and its raw materials; in material selection; in assessing building level embodied carbon; in benchmarking; and in the setting of reduction targets. Keywords: Benchmarking, embodied carbon, EPD, LCA, methodology. 1. Introduction and theoretical background The carbon embodied in buildings, from the use of construction materials which produce Carbon Diox- ide and other greenhouse gases during their life cy- cle, is an important proportion of our carbon emis- sions. International Energy Agency (IEA) estimate that embodied carbon accounted for 11% of global CO2 emissions in 2017, most of this from cement and steel manufacture [1]. IEA and the World Busi- ness Council for Sustainable Development Cement Sustainability Inititive (WBCSD-CSI) estimate the greenhouse gases emissions from cement manufacture are already 7% of our total global emissions [2]. IEA also note that cement demand has nearly doubled between 2000 and 2016, mainly due to increased de- mand in China, and latterly, India [1]. With almost all cement used in concrete, it is clear that concrete has a major influence on global greenhouse gas emis- sions. Environmental Product Declarations (EPD) are standardised presentations of the environmental im- pact of products. ISO 21930:2007 [3] was widely used by many of the EPD Programmes across Europe, but EN 15804 [4] has been developed following a man- date from the European Commission to harmonise the provision of EPD for construction products across Europe, ensuring that EPD to EN 15804 have a com- mon methodological approach to LCA and provision of environmental impacts. ISO 21930 was updated in 2017 to closely align with EN 15804 [5]. Construc- tionLCA’s infographic [6] shows that the numbers of EPD using EN 15804 have risen rapidly with over 7000 EPD available globally at the start of 2020. As a significant construction material, EPD have been produced for both cement and concrete prod- ucts, including both ready-mix concrete and precast concrete. As detailed in their paper [7], Anderson and Moncaster made a systematic review and analysis of all the published EPD globally for ready-mix concrete and its constituent materials (cement, aggregates and admixtures) at the end of 2019. They found 252 EPD for ready-mix concrete reporting data for over 2000 individual products, 108 EPD for cement and cemen- titious materials covering 118 products, 88 EPD for aggregates covering 117 products and 9 EPD for spe- cialist aggregates, and 16 EPD for admixtures coming from 25 EPD programmes in total. These EPD all represent products available in the market - includ- ing both national and regional industry average data provided by trade associations and manufacturer spe- cific data for both average and specific products, and many of these EPD, especially those for ready-mix concrete, provided individual data for more than one product, in some cases providing data for over 100 individual products in one EPD. These EPD were reviewed in terms of the data on "cradle to gate" embodied carbon coefficients (the Global Warming Potential Impact Indicator for Mod- 20 https://doi.org/10.14311/APP.2022.33.0020 https://creativecommons.org/licenses/by/4.0/ https://www.cvut.cz/en vol. 33/2022 Analysis of Concrete and Cement EPD ules A1-A3 within EPD) and their embodied energy (the Primary Energy and Secondary Energy Resource Indicators for Modules A1-A3 within EPD), together with other data such as clinker and cementitious con- tent for cements and 28-day strength for concretes, where they are provided. This paper describes how the information reported in the Systematic Review and Analysis can be used in EPD verification, materi- als selection, Embodied Carbon assessment at build- ing level, in benchmarking and in setting Improve- ment targets. 2. Previous Studies Hammond and Jones provided an overview of the embodied energy and carbon coefficients reported in academic and industry literature in their Inventory of Carbon and Energy database (ICE database) [8]. They found 112 datapoints for ready-mix concrete, 92 datapoints for cement and 36 datapoints for ag- gregate, though in relation to embodied carbon they note that "there is often an absence of such data". Damineli et al. reviewed 156 randomly selected papers from 1988-2009, 59 from Brazil (covering 604 concretes) and 97 International (covering 981 con- cretes), considering the embodied carbon of different concretes together with binder content, and 28 day compressive strength [9], and this work was updated by Scrivener et al. including examples of recent de- velopments, including data from concretes formulated with up to 70% replacement of binder by filler [10]. The ICE database was updated in 2011 [11] us- ing only 3 new datapoints for cement, aggregates and ready-mix concrete. the ICE database was updated again in 2019 [12] using embodied carbon data from published EPD. This version used 22 datapoints for ready-mix concrete (16 ready-mix sources listed), 14 datapoints for cement (4 sources listed) and 164 dat- apoints for aggregate (22 sources listed). Pomponi and Moncaster reviewed carbon coeffi- cients for cement and concrete in academic litera- ture, identifying 58 coefficients across the two prod- ucts [13]. Van Den Heede and De Belie similarly identified 12 datapoints for cement [14], Salas et al., reviewed the literature on LCA for cement and iden- tified 16 embodied carbon datapoints [15], Ganassali et al. identified 32 EPD for cement [16], Kurda, Sil- vestre and de Brito identified 17 cement datapoints and 20 aggregate datapoints [17] and Braga, Silvestre and de Brito identified 16 concrete datapoints [18]. Passer et al. have written about how EPD are be- ing used in the European Market [19] and Jelse and Peerens about how they can be used for Green Pub- lic Procurement [20]. Ganassali et al. discuss how they produced benchmark values for cement using 32 EPD, using the median value of the range for the reference value, with limit and target values set using the boundaries of the upper and lower quartiles of the range distribution [16]. Jones has developed embod- ied carbon benchmarks using the arithmetic mean of datapoints from selected EPD and others sources for each product [12]. 3. Description of the Systematic Review and Analysis of EPD and Summary of its Results 3.1. Methodology The review was conducted at the end of 2019. Dur- ing the data collection phase, EPD were downloaded from all the known EPD programmes, using EcoPlat- form [21] and the North American PCR Catalogue [22] and a general literature search. In the categori- sation phase, EPD were categorised into cement, dif- ferent concrete mixes, aggregates, and dividing the EPD which report multiples into a set of individual results. In the third phase, the data was extrapolated from the EPD cataloguing and tabulating like with like. The data included the embodied carbon coeffi- cients (GWP for A1-A3) together with other relevant data for all the separate products contained within each product group. In the fourth phase, visualisa- tions were developed and in the fifth phase, the re- sults were checked and verified. 3.2. Cement Embodied Carbon Coefficients Figure 1, taken from Anderson and Moncaster [7] which explains some of the reasons for variation, shows the embodied carbon coefficients for all the identified cement EPD plotted on a graph against clinker content. The types of cement (e.g., CEM I, CEM II etc) are differentiated using colour. 3.3. Ready-mix Concrete Embodied Carbon Coefficients Figure 2 from the same source [7], shows the ranges for Embodied Carbon coefficients for all the identi- fied products within ready-mix concrete EPD plot- ted against the 28-day strength where it has been provided. EPD ranges are identified based on the country of concrete production, with average EPD produced by national trade associations highlighted as a shaded range, labelled, e.g., "French Generic". This clearly shows that the ranges of impact vary significantly between countries, with French and Ger- man industry generic EPD having much lower im- pacts for the same 28-day strength than the corre- sponding US and Canadian; and all EPD from Mex- ico and Saudi Arabia having much higher impacts than those EPD from Australia and the U.A.E. for example. 4. Using the Embodied Carbon Coefficient Ranges for Cement and Concrete In the process of verifying the results, the authors found in several cases datasets which were significant 21 Jane Anderson, Alice Moncaster Acta Polytechnica CTU Proceedings outliers, and in these instances contacted the EPD programmes to check if there were possible errors in the data provided. In these cases, several errors were identified and EPD have been reissued. This led the authors to consider how the data collected in the Sys- tematic Review and Analysis could be used. 4.1. In EPD Verification The above example clearly illustrates how the Sys- tematic Review and Analysis can be used to check EPD for cement, concrete and aggregates to identify if the results are reasonable. For cement EPD, Figure 1 can be used to check the clinker content and embodied carbon are within the expected region of the graph, especially for CEM I, II, III and IV cements. The Systematic Review Anal- ysis also provided a box and whisker graph showing the range of embodied carbon for EPD by Country of Production and by type of cement (CEM I, CEM II etc), not included here, allowing verifiers to check the plausibility of embodied carbon results. Additional graphs are provided in the systematic review [7], but not included here, for CEM I and CEM II cement EPD showing the embodied carbon broken down by CO2 from calcination and from fuel use, and the pri- mary and secondary fuels use, broken down by re- newable and non-renewable sources, which again can be used to consider the plausibility of data provided in the EPD for verification. For concrete EPD for verification, we recommend checking them against Figure 3 which provides the embodied carbon ranges (mean and upper and lower quartile) for different countries and 28-day strengths to see that the embodied carbon is in the expected region of the graph. This graph also shows how many EPD results were included in each grouping. 4.2. In Material Selection Cement selection must be considered alongside the functionality of the concrete that is required. Figure 3 shows that that there is great variation in impact reported for any given strength, but that generally, there is an increase in embodied carbon per m3 as the 28-day strength of the concrete is increased. However Purnell cautions against the selection of low strength concretes over high strength concretes on the basis of their reduced embodied carbon, highlighting that significantly more of a low strength concrete may be required to fulfil a particular function [23]. A similar conclusion was drawn by Damineli et al. who showed that assessing CO2 per m3 and per unit of structural performance (kgCO2e/m3/MPa) suggested that C50 concrete was the optimal choice ide greater savings in embodied carbon (20-35%) than those achieved by replacing cement with pulverised fuel ash (10-25%) for example [23]. Carbon Intensities for ready-mix concretes with 28-day compressive strength over 10 MPa (from [7]) are shown in Figure 4. Many manufacturers are now able to provide EPD for the range of concretes that they product, for ex- ample using national tools such as the French BETie EPD tool [24] or industry association tools such as the CSI EPD Tool developed for WBCSD CSI [25] or that developed for the Norwegian Ready Mixed Con- crete Association, FABEKO. There is also the EPD tool developed by BASF for manufacturers to assess concretes [26] and other manufacturer specific EPD tools such as that for Tarmac [27]. Therefore, when selecting a concrete, we recom- mend that specifiers do the following: (1) consider the range of embodied carbon impacts shown in Fig- ure 3; (2) ask local concrete producers if they are able to provide information on the embodied carbon (car- bon footprint or EPD) for their concretes; (3) look for a producer able to provide a concrete at the lower end of the embodied carbon range for its strength; and (4) make sure that any impacts from extended transport distances do not outweigh the benefits of reduced embodied carbon in production - provided in Module A4 of EPD. 4.3. In Building LCA During early design stages, we recommend using re- gional generic data for concrete where available, as at this stage in the design this is the type of data recommended by EN 15978 [28]. If generic data is not available for a particular region, then we recom- mend identifying a region with similar technology for cement and concrete production and using Figure 2 to pick an appropriate embodied carbon value (from an industry generic EPD if available, or from the me- dian of the range otherwise). Ganassali recommends the median as it is not sensitive to the outliers in a sample composed of a small number of data [16]. At later stages of the design, it is recommended to use specific data, e.g., from manufacturer specific EPD based on the products you have chosen to use in the building (see section on material selection). 4.4. In Benchmarking Benchmarks can be provided for a product generally (e.g., cement or concrete) or for a specific product, such as CEM I cement or C30 concrete. Specify- ing benchmarks at the more specific level will en- sure that the products meeting the benchmark are not just lower carbon products, but products which have lower carbon impacts than other products with similar functionality. For concretes, it is important that the functionality is considered in defining the benchmark. Concretes with lower embodied carbon per m3 may have lower compressive strength, and this may lead to a requirement to use more con- crete which could have an adverse environmental impact. For situations where compressive strength is relevant, we recommend using Carbon Intensity (CO2eq/m3.MPa) as shown in Figure 4 to set bench- marks. 22 vol. 33/2022 Analysis of Concrete and Cement EPD Figure 1. Graph showing relationship of Embodied Carbon for cements by clinker content, source [7]. Figure 2. Embodied carbon per m3 concrete by compressive strength, shown for each country, source [7]. 23 Jane Anderson, Alice Moncaster Acta Polytechnica CTU Proceedings Figure 3. Box and Whisker graph showing mean, upper and lower quartiles of Embodied Carbon for ready-mix concretes from concrete EPD, by 28-day strength, source [7]. Figure 4. Box and Whisker Graph showing mean, upper and lower quartiles for Carbon Intensity ready-mix concretes, source [7]. 24 vol. 33/2022 Analysis of Concrete and Cement EPD In setting benchmarks, the geographical and re- lated technological situation should also be consid- ered - ideally a regional benchmark should ensure that at least some of the production achieves the benchmark, whilst also stretching producers adopt- ing "business as usual". 4.5. In Setting Reduction Targets The lower quartile ranges in Figure 3 and Figure 4 show the best performance shown by 25% and 50% of products with existing EPD, and therefore what should be achievable in setting long-term reduction targets for the majority of the market. This is also important information for manufacturers who wish to stay competitive in the carbon-aware market. 5. Conclusion This paper has demonstrated how the analysis of existing EPD for cement and concrete can pro- vide multiple useful information for Verifiers, Spec- ifiers, Designers, Building Assessors and Manufac- turers, including for EPD verification, material se- lection, building LCA, benchmarking and target set- ting. A similar detailed analysis of many other prod- ucts groups from the construction sector, particularly other materials and products with major impacts, would be useful for the construction industry as a whole. Acknowledgements The authors are very grateful to the Whitbybird Foun- dation for funding J. A.’s initial work on the origi- nal paper [7]; and to the Open-Oxford-Cambridge Arts and Humanities Research Council (AHRC grant number AH/R012709/1) Doctoral Training Partnership for fund- ing the continued project. Funding for A. M. came from the School of Engineering and Innovation at the Open University References [1] International Energy Agency (IEA). 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