EPD-IES-0029341:001

CEM II/A-LL 42.5 R

In line with our commitment to continuous improvement and meeting user needs, we have developed CEM II/A-LL 42,5 R. In addition to its strength class of 42,5 MPa, this cement belongs to the high early strength class (R). The presence of fine ground limestone enhances the plasticity and cohesion of concrete mixes. It improves flow properties, making pumping and placement easier, especially in high-rise buildings. Additionally, it has a reduced water cement ratio, which enhances the overall durability of the structure. The addition of limestone (LL) reduces the clinker content, which simultaneously has a positive impact on global CO₂ emissions compared to CEM I (ordinary Portland cement). Our cements comply with the MKC EN 197-1 harmonized European standard and are subject to assessment and performance verification procedures by a third party (an EU authorized body under System 1+ for assessment and verification of consistency of performance). The CE mark is affixed to the packaging and to the shipping documents in accordance with the Construction Products Regulation.

General information

EPD OwnerTITAN Usje AD Skopje
Registration numberEPD-IES-0029341:001
EPD typeEPD of a single product from a manufacturer/service provider
StatusValid
Version date2026-06-24
Validity date2031-06-23
Standards conformanceISO 14025:2006, EN 15804:2012+A2:2019/AC:2021
Geographical scopeGlobal
An EPD may be updated or depublished if conditions change. This is the latest version of the EPD.

Programme information

ProgrammeInternational EPD System
AddressEPD International AB Box 210 60 SE-100 31 Stockholm Sweden
Websitewww.environdec.com
E-mailsupport@environdec.com

Product category rules

CEN standard EN 15804 serves as the Core Product Category Rules (PCR)
Product Category Rules (PCR)2019:14 Construction products (EN 15804+A2) (version 2.0.1) 2.0.1
PCR review was conducted byThe Technical Committee of the International EPD System. See www.environdec.com for a list of members. Review chair: Rob Rouwette (chair), Noa Meron (co-chair). The review panel may be contacted via the Secretariat www.environdec.com/support.
Complementary Product Category Rules (c-PCR)PCR 2019:14-c-PCR-001 Being updated - Cement and building lime (EN 16908) (c-PCR to PCR 2019:14) (1.0.0) Version: 1.0.0
c-PCR review was conducted byThe Technical Committee of the International EPD System

Verification

Independent third-party verification of the declaration and data, according to ISO 14025:2006, via
Third-party verifierEUROCERT S.A.
Accredited byHellenic Accreditation System ESYD
Accredited certification body addressGreece
Procedure for follow-up of data during EPD validity involves third party verifier
*EPD Process Certification involves an accredited certification body certifying and periodically auditing the EPD process and conducting external and independent verification of EPDs that are regularly published. More information can be found in the General Programme Instructions on www.environdec.com.

Ownership and limitation on use of EPD

Limitations

EPDs within the same product category but published in different EPD programmes, may not be comparable. For two EPDs to be comparable, they shall be based on the same PCR (including the same first-digit version number) or be based on fully aligned PCRs or versions of PCRs; cover products with identical functions, technical performances and use (e.g. identical declared/functional units); have identical scope in terms of included life-cycle stages (unless the excluded life-cycle stage is demonstrated to be insignificant); apply identical impact assessment methods (including the same version of characterisation factors); and be valid at the time of comparison.

Ownership

The EPD Owner has the sole ownership, liability, and responsibility for the EPD.

Information about EPD Owner

EPD OwnerTITAN Usje AD Skopje
Contact person nameNatasha Bakreska, Ph.D. Environmental and Alternative Fuels Manager
Contact person e-mailnatasab@usje.mk
Organisation addressBul. Boris Trajkovski br.94 1000 Skopje North Macedonia
LCA PractitionerFrosina Dimoska, FrosinaD@usje.mk

Description of the organisation of the EPD Owner

Building materials manufacturer

Organisation images

Organisation logo

Product information

Product nameCEM II/A-LL 42.5 R
Product identificationCompressive Strength 28 days (MPa): ≥ 42,5 R
Product descriptionIn line with our commitment to continuous improvement and meeting user needs, we have developed CEM II/A-LL 42,5 R. In addition to its strength class of 42,5 MPa, this cement belongs to the high early strength class (R). The presence of fine ground limestone enhances the plasticity and cohesion of concrete mixes. It improves flow properties, making pumping and placement easier, especially in high-rise buildings. Additionally, it has a reduced water cement ratio, which enhances the overall durability of the structure. The addition of limestone (LL) reduces the clinker content, which simultaneously has a positive impact on global CO₂ emissions compared to CEM I (ordinary Portland cement). Our cements comply with the MKC EN 197-1 harmonized European standard and are subject to assessment and performance verification procedures by a third party (an EU authorized body under System 1+ for assessment and verification of consistency of performance). The CE mark is affixed to the packaging and to the shipping documents in accordance with the Construction Products Regulation.
Technical purpose of productThis cement is widely used in the construction of standard structures for any purpose (infrastructure, industry, housing, etc.), both for reinforced concrete and mass concrete structures. Ready-mix concrete plants are the largest users of this cement for concrete strength grades up to C40/50. Its balanced properties (hardness, setting time, heat during hydration) make this cement applicable in all climates and aggressive exposure classes. All standard concrete additives (retarders, plasticizers, etc.) can be used with our CEM II/B-P 42,5 R.
Manufacturing or service provision descriptionThe production of cement consists of several phases in which the main inputs are raw materials, fuel, water and energy, while the outputs consist of the finished products and waste. Cement Production Clinker, along with limestone, gypsum, fly ash, and pozzolana, is used to produce cement according to specific recipes. The process is monitored by mill operators and process control software. Clinker is stored in a silo, with three adjacent bunkers holding limestone (or clinker), gypsum, and tuff. Fly ash is stored in separate silos. Materials are fed into the cement mill either manually or automatically via weigh feeders. Milling produces cement, which is transferred by elevator to a classifier. Fine particles proceed to storage silos via air slides and another elevator, while coarse particles return to the mill. De-dusted exhaust gases are released into the atmosphere, and collected dust is returned to the process. Chemical additives are introduced to enhance grinding efficiency and product quality. Cement Packaging and Dispatch Finished cement is stored in silos, ready for dispatch either in bulk or in paper bags. For bagged cement, empty paper bags are loaded into the packing machine, which fills them with cement and "Usjemal" automatically. Each bag is weighed, and any bag not meeting the weight standard is rejected, torn, and the cement recycled back into the machine. Filled bags are cleaned using pressurized air, transported via belt conveyors to the palletizer, then to the stretching machine. Damaged bags are removed and replaced before loading.
Material propertiesVolumetric mass density: 3120 kg/m3
Volumetric mass density:
3120 kg/m3
Manufacturing siteTITAN Usje Bul. Boris Trajkovski br.94 1000 Skopje, Kisela Voda North Macedonia
UN CPC code3744. Portland cement, aluminous cement, slag cement and similar hydraulic cements, except in the form of clinkers
Geographical scopeGlobal

Product images

Content declaration

Hazardous and toxic substancesThe product does not contain any substances from the SVHC candidate list in concentrations exceeding 0.1% of its weight.
Product content
Content nameMass, kgPost-consumer recycled material, mass-% of productBiogenic material, mass-% of productBiogenic material1, kg C/declared unit
Clinker content750000
Other materials250000
Total1000000
Note 11 kg biogenic carbon is equivalent to 44/12 kg of CO2
Packaging materials
Material nameMass, kgMass-% (versus the product)Biogenic material1, kg C/declared unit
Paper bag0.0870.003
Wooden pallet0.2810.011
Stretch hood0.0070
Cover foil0.0020
Cover0.0010
Total0.3780.0140
Note 11 kg biogenic carbon is equivalent to 44/12 kg of CO2

LCA information

EPD based on declared or functional unitDeclared unit
Declared unit and reference flowCEM II/A-LL 42.5 R Mass: 1000 kg
Conversion factor to mass1
Are infrastructure or capital goods included in any upstream, core or downstream processes?
Datasources used for this EPDecoinvent database (general) ecoinvent 3.5 database Other database GCCA Industry EPD Tool for Cement and Concrete and Ecoinvent database (v5.2)
LCA SoftwareGCCA Industry EPD Tool v5.2
Additional information about the underlying LCA-based information

Cut-off rules: Cut-off criteria were employed to include all the environmental impact sources while ensuring the study to be complete, relevant, accurate and consistent. Cut-off criteria considered for this study are below:

• Mass – For mass flow less than 0.5% of the total mass flow environmental impact source may be eliminated with the stipulation that impact would be marginal.

• Energy – For energy flow less than 0.5% of the total energy flow environmental impact source may be eliminated under that condition that environmental impact is not a concern.

• Environment – For those flows (mass or energy flow) less than 0.5% of the total respective flow with significant environmental concern impact source must be included for the study.

Allocation: The allocation has been avoided where that was possible. Production was split into two sub-processes, clinker and cement, and the associated input and output data for each sub-process were recorded. When data could not be directly attributed to a specific product, they were assigned physical properties (mass). No by-products occur during clinker and cement production; therefore, there is no need for allocations in by-products. For water (consumed and recycled), waste and emissions allocation, the “clinker to cement ratio” was used for allocating the volumes to clinker or cement respectively. Since the rule pertaining to allocation applies only when there are two or more by-products produced from a single stream, the allocation rule was not considered in this study, as the operation in TITAN Usje cement production Plant resulted in no more than one product from each stream.

Assumptions and approximations: The cradle to gate study approach was adopted. In this study, an assumption was made on the data for the specific usage of solar electrical energy produced on site. The rest of the data considered for this study was obtained from primary sources. Another assumption was made for road and sea transportation. A >32 metric ton lorry, EURO6 and bulk carrier for dry goods were used respectively. The cement recipe (materials percentage participation) was defined by the pre-verified and automated ERP system (SAP) that the company uses. An approximation was made when calculating the packaging waste, as the data was taken from a packaging normative created to describe the packaging of all the products individually.

Version of the EN 15804 reference packageEF Reference Package 3.1
Characterisation methodsLCI results are classified into impact categories, each with a category indicator (ISO 14044:2006). In the present study, the environmental indicators (impact categories) are reported according to the PCR 2019:14 “Construction products”, c-PCR-001 “Cement and building lime (EN 16908:2017)" and EN 15804:2012+A2/AC:2021.
Technology description including background systemThe product considered is Portland cement according to MKC EN 197. The product consists of Portland cement clinker, limestone, gypsum and natural pozzolana. The raw materials (other than clinker) content is between 20 and 30 % (mass).
Scrap (recycled material) inputs contribution levelLess than 10% of the GWP-GHG results in modules A1-A3 come from scrap inputs

Data quality assessment

Description of data quality assessment and reference yearsIn terms of data collection and quality requirements ISO 14044 was applied. The data concerning the modules A1 (raw material supply), A2 (transportation) and A3 (product manufacturing) were provided by Titan Usje and involved all input and output materials to the plant, the consumed utilities (energy, water) and the distances and means of transport for each input stream. Regarding the electricity mix, the default values in GCCA's Industry EPD Tool for Cement and Concrete LCA database (v 5.2) were used. This web-based tool, developed by the Global Cement and Concrete Association, is a calculation tool for EPDs of clinker, cement, concrete, and precast elements. The GCCA EPD tool is developed by Quantis https://quantis-intl.com/ and verified by Studio Fieschi http://www.studiofieschi.it/en. The International EPD® System, which provides the framework to develop and publish EPDs based on I1SO 14025 and EN 15804, gives the final approval of the tool's compliance with the rules. As a part of the study, data authentication was carried out to understand the assurance level provided by the collected data. This authentication process enabled TITAN Usje to avoid any ambiguities that may encircle in the future. The GCCA EPD Tool database was used for the missing data. Generic data used in this study relate to: - CO2 emission factors for different transportation ways - Specific emission factor of used energy mix (kg CO2/kWh) The required data were sourced from several reliable sources: - The company’s ERP system (SAP), - Flow meters monitoring water consumption and recycling, - Continuously recorded emissions data obtained from monitoring systems installed at each cement plant (MEAC). The monitored emissions include Dust, NOx and SO2. Reference period: February - May 2025
Electricity data
Electricity used in the manufacturing process in A3 (A5 for services)
Type of electricity mixSpecific electricity mix as generated, or purchased from an electricity supplier, demonstrated by a contractual instrument
Energy sourcesHydro14.8%
Wind9.3%
Solar3%
Biomass4%
Geothermal0.4%
Waste1.2%
Nuclear22.5%
Natural gas20.9%
Coal22.3%
Oil1.6%
Peat0%
Other0%
GWP-GHG intensity (kg CO2 eq./kWh)0.95 kg CO2 eq./kWh
CO2 uptake associated with carbonation and its assumptions
Production stage (module A)Excluded
Use stage (module B)Excluded
End-of-Life stage (module C)Excluded
Beyond product life cycle (Module D)Excluded

System boundary

Description of the system boundarya) Cradle to gate with modules C1-C4 and module D (A1-A3 + C + D).
Excluded modulesYes, there is an excluded module, or there are excluded modules
Justification for the omission of modulesThe scope of this study is “Cradle to gate” covering the product stage (modules A1-A3), since the product fulfils the three conditions required by EN 15804:2012+A2:2019, about the exclusion of modules C1-C4 and D. The EPD covers the product stage (“cradle to gate”, A1-A3), since the three criteria of EN 15804 are met for the exclusion of stages B1-B7, C1-C4 and D. Modules C1–C4 and D are not included in this EPD, and the environmental impacts of the end-of-life stage are therefore not covered.

Declared modules

Product stageConstruction process stageUse stageEnd of life stageBeyond product life cycle
Raw material supplyTransportManufacturingTransport to siteConstruction installationUseMaintenanceRepairReplacementRefurbishmentOperational energy useOperational water useDe-construction demolitionTransportWaste processingDisposalReuse-Recovery-Recycling-potential
ModuleA1A2A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
Modules declaredXXXNDNDNDNDNDNDNDNDNDNDNDNDNDND
GeographyGlobalGlobalRepublic of North MacedoniaN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/AN/A
Share of specific data100%--------------
Variation - products--------------
Variation - sites--------------
DisclaimerThe share of specific/primary data and both variations (products and sites) refer to GWP-GHG results only.

Description of the process flow diagram(s)

Process flow diagram of the product system, divided into the life-cycle stages and modules (or other division of the product life cycle, if defined in the PCR), showing the main processes included and the system boundary of the LCA. The diagram shall make it clear when the end-of-waste state is reached for main input flows of reused/recycled materials and recovered energy, and for output flows of reused/recycled materials and recovered energy exiting the end-of-life stage.

Process flow diagram(s) related images

Default scenario

Name of the default scenarioThe LCl results for CEM II/A-LL 42.5 R for the reference period
Description of the default scenarioThe LCI results (calculated by GCCA EPD tool) are presented as environmental indicators according to the EN 15804.

Additional scenario 1

Name of the additional scenario50% increase in solar energy input in the energy mix for the production of cement
Description of the additional scenarioIncreasing the share of solar energy in the electricity mix by 50% decreases the emitted CO2eq by 0,283 kg.

Environmental performance

The estimated impact results are only relative statements, which do not indicate the endpoints of the impact categories, exceeding threshold values, safety margins and/or risks.

Mandatory environmental performance indicators according to EN 15804

Impact categoryIndicatorUnitA1-A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
Climate change - totalGWP-totalkg CO2 eq.7.79E+2NDNDNDNDNDNDNDNDNDNDNDNDNDND
Climate change - fossilGWP-fossilkg CO2 eq.7.79E+2NDNDNDNDNDNDNDNDNDNDNDNDNDND
Climate change - biogenicGWP-biogenickg CO2 eq.5.14E-1NDNDNDNDNDNDNDNDNDNDNDNDNDND
Climate change - land use and land-use changeGWP-luluckg CO2 eq.1.05E-1NDNDNDNDNDNDNDNDNDNDNDNDNDND
Ozone depletionODPkg CFC-11 eq.5.51E-6NDNDNDNDNDNDNDNDNDNDNDNDNDND
AcidificationAPmol H+ eq.1.95E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
Eutrophication aquatic freshwaterEP-freshwaterkg P eq.4.80E-2NDNDNDNDNDNDNDNDNDNDNDNDNDND
Eutrophication aquatic marineEP-marinekg N eq.2.59E-1NDNDNDNDNDNDNDNDNDNDNDNDNDND
Eutrophication terrestrialEP-terrestrialmol N eq.6.42E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
Photochemical ozone formationPOCPkg NMVOC eq.2.07E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
Depletion of abiotic resources - minerals and metalsADP-minerals&metals1kg Sb eq.2.28E-3NDNDNDNDNDNDNDNDNDNDNDNDNDND
Depletion of abiotic resources - fossil fuelsADP-fossil1MJ, net calorific value5.43E+3NDNDNDNDNDNDNDNDNDNDNDNDNDND
Water useWDP1m3 world eq. deprived4.33E+1NDNDNDNDNDNDNDNDNDNDNDNDNDND
AcronymsGWP-fossil = Global Warming Potential fossil fuels; GWP-biogenic = Global Warming Potential biogenic; GWP-luluc = Global Warming Potential land use and land use change; ODP = Depletion potential of the stratospheric ozone layer; AP = Acidification potential, Accumulated Exceedance; EP-freshwater = Eutrophication potential, fraction of nutrients reaching freshwater end compartment; EP-marine = Eutrophication potential, fraction of nutrients reaching marine end compartment; EP-terrestrial = Eutrophication potential, Accumulated Exceedance; POCP = Formation potential of tropospheric ozone; ADP-minerals&metals = Abiotic depletion potential for non-fossil resources; ADP-fossil = Abiotic depletion for fossil resources potential; WDP = Water (user) deprivation potential, deprivation-weighted water consumption
Disclaimer 1The results of this environmental impact indicator shall be used with care as the uncertainties of these results are high or as there is limited experience with the indicator

Additional mandatory environmental performance indicators

Impact categoryIndicatorUnitA1-A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
Climate change - GWP-GHGGWP-GHG1kg CO2 eq.7.79E+2NDNDNDNDNDNDNDNDNDNDNDNDNDND
AcronymsGWP-GHG = Global warming potential greenhouse gas.
Disclaimer 1The GWP-GHG indicator is termed GWP-IOBC/GHG in the ILCD+EPD+ data format. The indicator accounts for all greenhouse gases except biogenic carbon dioxide uptake and emissions and biogenic carbon stored in the product. As such, the indicator is identical to GWP-total except that the CF for biogenic CO2 is set to zero.

Additional voluntary environmental performance indicators according to EN 15804

Impact categoryIndicatorUnitA1-A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
Particulate matter emissionsPMDisease incidence2.63E-5ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Ionizing radiation - human healthIRP1kBq U235 eq.1.02E+1ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Eco-toxicity - freshwaterETP-fw2CTUe1.09E+3ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Human toxicity - cancer effectsHTP-c2CTUh1.58E-6ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Human toxicity - non-cancer effectsHTP-nc2CTUh3.24E-5ND ND ND ND ND ND ND ND ND ND ND ND ND ND
Land-use related impacts/soil qualitySQP2Dimensionless4.02E+3ND ND ND ND ND ND ND ND ND ND ND ND ND ND
AcronymsPM = Potential incidence of disease due to particulate matter emissions; IRP = Potential human exposure efficiency relative to U235; ETP-fw = Potential comparative toxic unit for ecosystems; HTP-c = Potential comparative toxic unit for humans; HTP-nc = Potential comparative toxic unit for humans; SQP = Potential soil quality index.
Disclaimer 1This impact category deals mainly with the eventual impact of low dose ionizing radiation on human health of the nuclear fuel cycle. It does not consider effects due to possible nuclear accidents, occupational exposure nor due to radioactive waste disposal in underground facilities. Potential ionizing radiation from the soil, from radon and from some construction materials is also not measured by this indicator.
Disclaimer 2The results of this environmental impact indicator shall be used with care as the uncertainties of these results are high or as there is limited experience with the indicator.

Resource use indicators according to EN 15804

IndicatorUnitA1-A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
PEREMJ, net calorific value2.48E+2NDNDNDNDNDNDNDNDNDNDNDNDNDND
PERMMJ, net calorific value2.62E+2NDNDNDNDNDNDNDNDNDNDNDNDNDND
PERTMJ, net calorific value5.10E+2NDNDNDNDNDNDNDNDNDNDNDNDNDND
PENREMJ, net calorific value5.42E+3NDNDNDNDNDNDNDNDNDNDNDNDNDND
PENRMMJ, net calorific value1.53E+1NDNDNDNDNDNDNDNDNDNDNDNDNDND
PENRTMJ, net calorific value5.43E+3NDNDNDNDNDNDNDNDNDNDNDNDNDND
SMkg3.21E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
RSFMJ, net calorific value2.89E+1NDNDNDNDNDNDNDNDNDNDNDNDNDND
NRSFMJ, net calorific value2.66E+1NDNDNDNDNDNDNDNDNDNDNDNDNDND
FWm32.19E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
AcronymsPERE = Use of renewable primary energy excluding renewable primary energy resources used as raw materials; PERM = Use of renewable primary energy resources used as raw materials; PERT = Total use of renewable primary energy resources; PENRE = Use of non-renewable primary energy excluding non-renewable primary energy resources used as raw materials; PENRM = Use of non-renewable primary energy resources used as raw materials; PENRT = Total use of non-renewable primary energy re-sources; SM = Use of secondary material; RSF = Use of renewable secondary fuels; NRSF = Use of non-renewable secondary fuels; FW = Use of net fresh water.

Waste indicators according to EN 15804

IndicatorUnitA1-A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
HWDkg5.47E-3NDNDNDNDNDNDNDNDNDNDNDNDNDND
NHWDkg6.57E-2NDNDNDNDNDNDNDNDNDNDNDNDNDND
RWDkg1.91E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
AcronymsHWD = Hazardous waste disposed; NHWD = Non-hazardous waste disposed; RWD = Radioactive waste disposed.

Output flow indicators according to EN 15804

IndicatorUnitA1-A3A4A5B1B2B3B4B5B6B7C1C2C3C4D
CRUkg0.00E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
MFRkg3.61E-1NDNDNDNDNDNDNDNDNDNDNDNDNDND
MERkg0.00E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
EEEMJ, net calorific value0.00E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
EETMJ, net calorific value0.00E+0NDNDNDNDNDNDNDNDNDNDNDNDNDND
AcronymsCRU = Components for re-use; MFR = Materials for recycling; MER = Materials for energy recovery; EEE = Exported electrical energy; EET = Exported thermal energy.

Abbreviations

Not applicable 

References

a) General Programme Instructions of International EPD System. Version. 5.0.1 

b) PCR 2019:14.. Version 2.0.1 N Product Category rules | Construction products | The International EPD System ame 

c) ISO 14040:2006 Environmental management - Life Cycle Assessment - Principles and framework 

d) ISO 14044:2006 Environmental management - Life Cycle Assessment - Requirements and guidelines 

e) EN 16908:2017+A1:2022 Cement and building lime - Environmental product declarations - Product category rules complementary to EN 15804 

f) ISO 14025:2006 Environmental labels and declarations - Type IIl environmental declarations - Principles and procedures 

g) EN 197-1:2012 - Part 1: Composition, specifications and conformity criteria for common cements 

h) Industry EPD Tool for Cement and Concrete (https://concrete-epd-tool.org/)

- User Guide (v5.2, International version, 24 June 2025)

- LCA Model (v5.2, International version, 17 July 2025) 

- LCA Database (v5.2, 24 June 2025) 

Version history

Version 1, 2026-06-24

Original version of the EPD