Carbon footprint case study on Proxxima system-based composite rebar
ExxonMobil Technology and Engineering Company (EMTEC) conducted an ISO 14067 life cycle assessment (LCA) study comparing Proxxima systems-based glass fiber reinforced polymer (Proxxima GFRP) rebar to steel reinforcement bar, completed in May 2025. The 2025 comparative study serves as an illustrative example of the relative global warming potential (GWP) of a Proxxima systems-based composite part vs. a similar part made from steel.
System boundaries from the 2023 and 2025 LCA studies
1For additional information on the Cradle-to-Proxxima™ resin system manufacturing gate (boundary 1), please refer to the 2023 LCA study summary here.
2For additional information on the Cradle-to-Proxxima GFRP rebar manufacturing gate (boundary 2) and Cradle-to-Proxxima GFRP rebar End-of-Life (boundary 3), please refer to the 2025 LCA study summary here.
Proxxima GFRP rebar has a carbon footprint of product (CFP) estimate ~70% lower than the reference steel rebar case**
*Source: Carbon Footprint of Product of Reinforcing Bars: Steel and ProxximaTM Resin containing Glass Fiber Reinforced Polymer (GFRP) in Construction Applications, May 2025, prepared by ExxonMobil Technology and Engineering Company. The study was conducted to be in accordance with ISO 14067:2018 (Greenhouse gases – Carbon footprint of products – Requirements and guidelines for quantification). The study was confirmed to be conducted according to and in compliance with ISO 14067:2018 by an independent third party (Sphera Solutions, Inc.) critical review which followed ISO 14071:2024 to support comparative environmental footprint communications as defined in ISO 14026:2018.
**Sphera Solutions, Inc., "Process data set: Steel rebar; blast furnace route and electric arc furnace route; production mix, at plant; 1kg (en)," [Online]. Available: https://lcadatabase.sphera.com/2024/xml-data/processes/7f2946df-be83-4dad-a34f-1be5f9845121.xml. [Accessed 14 4 2025].
For additional information, please refer to the LCA study summary here.
Proxxima GFRP rebar’s estimated CFP is ~40% lower than steel rebar from the scrap-EAF steel production route
Proxxima GFRP rebar’s estimated CFP is ~80% lower than steel rebar from the BF-BOF steel production route (majority of global steel production)
*Source: Carbon Footprint of Product of Reinforcing Bars: Steel and ProxximaTM Resin containing Glass Fiber Reinforced Polymer (GFRP) in Construction Applications, May 2025, prepared by ExxonMobil Technology and Engineering Company. The study was conducted to be in accordance with ISO 14067:2018 (Greenhouse gases – Carbon footprint of products – Requirements and guidelines for quantification). The study was confirmed to be conducted according to and in compliance with ISO 14067:2018 by an independent third party (Sphera Solutions, Inc.) critical review which followed ISO 14071:2024 to support comparative environmental footprint communications as defined in ISO 14026:2018.
For additional information, please refer to the LCA study summary here.
Cradle-to-end-of-life CFP estimates for installed rebar in industrial applications show that Proxxima GFRP has a potentially lower GWP than installed steel rebar‡
‡Cradle-to-end-of-life estimation assumes equivalent areas of steel and Proxxima GFRP rebar provide the same function (both products were installed with the same concrete mixture and thickness).
**Sphera Solutions, Inc., "Process data set: Steel rebar; blast furnace route and electric arc furnace route; production mix, at plant; 1kg (en)," [Online]. Available: https://lcadatabase.sphera.com/2024/xml-data/processes/7f2946df-be83-4dad-a34f-1be5f9845121.xml. [Accessed 14 4 2025].
For additional information, please refer to the LCA study summary here.
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Disclaimers:
- THE INFORMATION PROVIDED CONSTITUES ESTIMATES ONLY. THE SYSTEM BOUNDARIES ARE AS FOLLOWS:
- BOUNDARY 1: THE BOUNDARY FOR THE CARBON FOOTPRINT ESTIMATES IS CRADLE TO GATE. THIS IS NOT A FULL PRODUCT LIFE CYCLE (CRADLE TO GRAVE) ASSESSMENT.
- BOUNDARY 2: THE BOUNDARY FOR THE CARBON FOOTPRINT ESTIMATES IS CRADLE-TO-PROXXIMA™ GFRP REBAR MANUFACTURING GATE. THIS IS NOT A FULL LIFE CYCLE (CRADLE TO GRAVE) ASSESSMENT.
- BOUNDARY 3: THE BOUNDARY FOR THE CARBON FOOTPRINT ESTIMATES IS CRADLE-TO-PROXXIMA™ GFRP REBAR END-OF-LIFE.
- The Carbon Footprint of Product (CFP) estimates are represented in units corresponding to the CO2 equivalent per declared unit (boundary 1: per liter, boundary 2: per 100 feet of rebar, boundary 3: per square meter of concrete pad or per mile of lane), utilizing the Intergovernmental Panel on Climate Change (IPCC) emissions metrics of Global Warming Potential (GWP) under the 100 year time horizon. The GWP metric, used by policy makers, is intended to quantify and communicate potential global warming impacts of different substances and emissions relative to that of CO2. The emissions estimates are relative expressions only and do not predict actual impacts, the exceeding of threshold, safety margins, or risks.
- Third party sources may impose their own disclaimers and limitations. The estimates and other information provided are intended for a business audience. Recipients of this information (“Recipients”) should not rely upon the estimate(s) or other information provided herein; rather, Recipients should conduct their own due diligence. We (and our affiliates) disclaim all liabilities and warranties, express or implied, regarding the information provided, including as to the accuracy, completeness or fitness for a particular purpose, and disclaim any obligation to provide any updates. Recipients assume all risk in use of the estimate(s) and other information provided, including compliance with any applicable laws.
- Exxon Mobil Corporation, of which ExxonMobil Product Solutions Company is a division, has numerous affiliates. For convenience and simplicity, terms such as Materia, ExxonMobil, Esso, Corporation, company, EM, our, we, and its are sometimes used as abbreviated references to specific affiliates or affiliate groups. Abbreviated references describing global or regional operational organizations, and global or regional business lines are also sometimes used for convenience and simplicity. Nothing contained herein or in other documents or information provided is intended to override the corporate separateness of affiliated companies.
- Any use of the estimates or other information provided is subject to the terms above.
- ©2025 ExxonMobil Product Solutions Company, a division of Exxon Mobil Corporation. ExxonMobil, the ExxonMobil logo, the interlocking “X” device, PROXXIMA, PROXXIMA Logo and X Logo and other product or service names used herein are trademarks of ExxonMobil, unless indicated otherwise.
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