Punching Above its Weight: Life Cycle Energy Accounting and Environmental Assessment of Vanadium Microalloying in Reinforcement Bar Steel
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The manuscript presents a detailed analysis of embodied energy and carbon footprint reduction enabled by microalloying of steel, thereby providing a rich global perspective of the (outsized) role of chemical elements added in trace concentrations on the overall footprint of the construction industry. As such, the manuscript addresses an important and timely topic at the intersection of materials criticality, structural performance, life cycle assessment, and policy interventions.
The United Nations estimates that the worldwide energy consumption of buildings accounts for 30—40% of global energy production, underlining the importance of the judicious selection of construction materials. Much effort has focused on the use of high-strength low-alloy steels in reinforcement bars whose economy of materials use is predicated upon improved yield strengths in comparison to low-carbon steels. While microalloying is known to allow for reduced steel consumption, a sustainability analysis in terms of embodied energy and CO 2 has not thus far been performed. Here we calculate the impact of supplanting lower grade reinforcement bars with higher strength vanadium microalloyed steels on embodied energy and carbon footprint. We find that the increased strength of vanadium microalloyed steel translates into substantial material savings over mild steel thus reducing the total global fossil carbon footprint by as much as 0.385%. A more granular analysis pegs savings for China and the European Union at 1.01 and 0.19%, respectively, of their respective emissions.