Cradle-to-gate life cycle assessment of CFRP reinforcement for concrete structures: Calculation basis and exemplary application

The building industry accounts for a significant amount of CO2 emissions worldwide, at which the building material concrete with its binder cement is responsible for a considerable share. Consequently, it is inevitable to strive for solutions to reduce the amount of concrete used in the building industry. One possible approach is to use reinforcement made of carbon fiber-reinforced polymers (CFRP) combined with appropriate new structural design approaches to reduce the dimensions and thus the weight of concrete building components. CFRP reinforcement is characterized by a higher tensile strength and favorable properties regarding corrosion resistance compared to conventional steel reinforcement. However, the production of carbon fibers is resource- and energy-intense. This research study evaluates the environmental performance of CFRP reinforcement in concrete structures in accordance with the current state of data availability and standardization. A cradle-to-gate life cycle assessment is conducted. Design values allowing for a preliminary estimation of the environmental performance of CFRP reinforcement are provided, at which maximum transparency regarding the identification process and the consulted environmental data is set as top priority. The addressed impact categories include the abiotic depletion of fossil resources (ADPf), the acidification potential (AP) and the global warming potential (GWP). A comparison of CFRP and conventional steel reinforcement shows the comparatively high environmental impact of CFRP reinforcement amongst all considered impact categories. A subsequent assessment by means of considering the superstructure (deck and railing) of built pedestrian bridge examples including a carbon concrete bridge, a conventional reinforced concrete bridge and a mild steel bridge, indicates otherwise: Due to a significant reduction in self-weight, the GWP and ADPf of the carbon concrete bridge show the comparatively lowest values. These results prove the economic potential of using CFRP as reinforcement based on a quantitative evaluation of the ecologic impact. (C) 2020 The Author(s). Published by Elsevier Ltd.

Automated summary

The building industry is a significant contributor to global CO2 emissions, particularly due to the use of concrete with cement binder. Utilizing carbon fiber-reinforced polymers (CFRP) as reinforcement can reduce the amount of concrete used in building components, thus decreasing environmental impact.