Cement MFA

Methodology

Stock extrapolation

The stock extrapolation method for cement resembles largely the methodology represented in the Model overview. The stock projection was obtained by fitting a logistic funtion on the logarithm of GDP, independently for each region and stock type. To decrease the degrees of freedom, function parameters were set or bounded. Saturation levels were estimated from historic trends and expert judgement. Stock expansion rates in low-stock regions are limited through an upper bound set as the observed stock growth rate of China. Similarly, the point where the logistic function reaches 50 percent of saturation is constrained through a lower bound informed by historic Chinese stock expansion dynamics.

Processes

The following table lists the processes that are modelled in the cement MFA.

Name
System environment
Production: Clinker
Production: Cement
Production: Product
Use phase
End of life
Atmosphere
Carbonation

Dimensions

The following table presents the dimensions over which parameters and variables (stocks and flows incl. trades) are defined in the cement MFA.

Name Letter
Time t
Region r
Stock Type s
Historic Time h
Product Material m
Product Application a
Waste Type w
Waste Size p
Carbonation Location c

Stocks

The following table presents the processes that are modelled as stocks in the cement MFA with their respective dimensions and the lifetime model that is employed. The historic_cement_in_use stock represents the weight of cement in the historic in-use stock. The in_use stock represents the weight of the final product, i.e., the weight of both concrete and mortar. Cement contents of this stock can be inferred by applying a cement-to-product ratio.

Dimensions Name Process Stock Type Lifetime Model
t, r, s, m, a in_use Use phase StockDrivenDSM LogNormalLifetime
t, r, m, a, s End of life End of life InflowDrivenDSM FixedLifetime
t, r, m, s Atmosphere Atmosphere SimpleFlowDrivenStock
t, r, m, c, s carbonated_co2 Carbonation InflowDrivenDSM FixedLifetime

Flows

The following table presents all flows in the cement MFA with their respective dimensions and the processes that they connect.

Dimensions Origin Process Destination Process
t, r, m, s System environment Production: Clinker
t, r, m, s Production: Clinker Production: Cement
t, r, m, s Production: Clinker System environment
t, r, m, s System environment Production: Cement
t, r, m, s Production: Cement Production: Product
t, r, m, s Production: Cement System environment
t, r, m, s System environment Production: Product
t, r, s, m, a Production: Product Use phase
t, r, m, a, s Use phase End of life
t, r, m, a, s End of life System environment
t, r, m, s Production: Clinker Atmosphere
t, r, m, c, s Atmosphere Carbonation

Parameters

The following table presents all exogenous parameters in the cement MFA with their respective dimensions and the sources of the respective input data. If no input data source is specified, the parameter is currently estimated based on expert judgement.

Dimensions Name Description Sources
r, s stock_type_split Split of cement production into different stock types. (Andrew, 2025)1, (Xi et al., 2016)2
h, r cement_production Historic cement production volume for each region and year. (Andrew, 2025)1
h, r cement_trade Historic net cement trade flows per region and year. (Andrew, 2025)1, (House, 2024)3, (Division, 2025)4, (U. S. Geological Survey, 2024)5
h, r clinker_ratio Historic clinker-to-cement ratio for each region. (Andrew, 2025)1, (House, 2024)3, (Division, 2025)4, (U. S. Geological Survey, 2024)5
h, r, s use_lifetime_mean Mean lifetime of historic cement stocks by region and stock type. (Andrew, 2025)1, (Posted, 2025)6, (Hatayama et al., 2010)7, (Cao et al., 2017)8, (Cao et al., 2021)9, (Hosseinijou & Mansour, 2021)10, (Deetman et al., 2020)11, (Kapur et al., 2008)12
nan use_lifetime_rel_std Relative standard deviation of lifetime of cement in buildings and infrastructure.
t, r population Historic and projected population for each region and model year. (International Monetary Fund, 2021)13, (India Department of Economic Affairs, n.d.)14, (India Ministry of Health, 2019)15, (IIASA, 2024)16, (James et al., 2012)17, (Arujo et al., 2021)18, (World Bank, 2023a)19, (IIASA, 2024)16, (Crespo Cuaresma, 2017)20, (Dellink et al., 2017)21, (KC et al., 2024)22, (United Nations, Department on Economic and Social Affairs, Population Division, 2022)23, (World Bank, 2023b)24, (Gapminder, n.d.)25, (James et al., 2012)17, (Bolt et al., 2014)26
t, r gdppc Historic and projected GDP per capita for each region and model year. (International Monetary Fund, 2021)13, (India Department of Economic Affairs, n.d.)14, (India Ministry of Health, 2019)15, (IIASA, 2024)16, (James et al., 2012)17, (Arujo et al., 2021)18, (World Bank, 2023a)19, (IIASA, 2024)16, (Crespo Cuaresma, 2017)20, (Dellink et al., 2017)21, (KC et al., 2024)22, (United Nations, Department on Economic and Social Affairs, Population Division, 2022)23, (World Bank, 2023b)24, (Gapminder, n.d.)25, (Bolt et al., 2014)26, (James et al., 2012)17, (Bolt et al., 2014)26
nan cement_losses Share of cement lost during cement production. (Kaufmann et al., 2024)27
nan clinker_losses Share of clinker lost during clinker production. (Kaufmann et al., 2024)27
m product_density Material density associated with each product.
r, a product_application_split Share of product output allocated to each application by region. (Andrew, 2025)1, (Kaufmann et al., 2024)27
r, m product_material_split Share of product output allocated to each material by region. (Andrew, 2025)1, (Kaufmann et al., 2024)27
m, a product_material_application_transform Transformation matrix linking product materials to applications.
a product_cement_content Cement content per cubic meter of product application. (Kaufmann et al., 2024)27
r stock_saturation_level Saturation level of in-use cement stock in each region. (Andrew, 2025)1
r industrialized_regions List of regions considered industrialized for stock extrapolation. (Andrew, 2025)1
nan clinker_cao_ratio Mass fraction of CaO contained in clinker. (Kaufmann et al., 2024)27
m cao_carbonation_share Share of CaO that is available for carbonation per material. (Kaufmann et al., 2024)27
nan cao_emission_factor Process CO2 emission factor from producing CaO.
nan ckd_cao_ratio CaO content ratio present in cement kiln dust. (Kaufmann et al., 2024)27
nan ckd_landfill_share Share of cement kiln dust disposed to landfill. (Kaufmann et al., 2024)27
r, a carbonation_rate Carbonation rate for exposed stocks by region and application. (Andrew, 2025)1, (Kaufmann et al., 2024)27
r, a carbonation_rate_buried Carbonation rate for buried stocks by region and application. (Andrew, 2025)1, (Kaufmann et al., 2024)27
nan carbonation_rate_coating Carbonation rate modifier factoring in coated cement products. (Andrew, 2025)1, (Kaufmann et al., 2024)27
nan carbonation_rate_co2 Carbonation rate modifier factoring in increased atmospheric CO2 concentrations. (Andrew, 2025)1, (Kaufmann et al., 2024)27
nan carbonation_rate_additives Carbonation rate modifier factoring in cement additives. (Andrew, 2025)1, (Kaufmann et al., 2024)27
a product_thickness Average thickness assumed for each product application. (Kaufmann et al., 2024)27
r, w waste_type_split Share of end-of-life cement flows by waste type and region. (Andrew, 2025)1, (Kaufmann et al., 2024)27
r, w, p waste_size_share Share of waste distributed across size classes per region and type. (Andrew, 2025)1, (Kaufmann et al., 2024)27
w, p waste_size_min Minimum particle size represented for each waste type and class.
w, p waste_size_max Maximum particle size represented for each waste type and class.

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