Fostering a circular economy and carbon sequestration for construction materials workshop report:

Abstract

The construction sector is increasingly focused on improving energy and material efficiency to reduce its environmental impact. One promising approach gaining traction is the shift from a traditional linear economic model (extract, make, use, discard) to a circular model. In a circular economy (CE), materials are designed to have lower environmental impacts and are retained in the economy for as long as possible, thereby reducing resource depletion, environmental impact, and waste generation, while creating new business opportunities and jobs. Concrete, a widely used construction material, is a significant contributor to CO2 emissions due to cement production. Efforts are underway to transition the cement and concrete industries to a CE. Strategies include infrastructure design to optimize concrete use and enable repair and reuse, as well as advanced material design such as the use of alternative cementitious materials, improved energy efficiency in production, and carbon capture from production and sequestration in concrete. However, challenges hinder the transition to a CE, including the industry's established technologies and supply chains, the need for demonstrated reliability of new materials, and lack of a trained workforce capable of designing and constructing with lowcarbon materials. To overcome these challenges requires a collaborative, systems-level approach, with clear goals, harmonized metrics, robust assessment tools, standards development, workforce training, and coordinated regulatory efforts. The U.S. National Institute of Standards and Technology (NIST) can support the transition to a CE by advancing measurement science, developing data resources and modeling tools, participating in standards development, and convening necessary stakeholders to facilitate collaborative engagement.