Speaker
Description
The global drive towards decarbonization places a significant emphasis on industries such as the construction sector, which still accounts for 37% of emissions. For countries to achieve their climate change mitigation goals, particularly in regions such as Morocco, which is experiencing significant infrastructure development, the concrete industry must undergo a radical transformation. The challenge is no longer to achieve incremental efficiency gains; rather, it is to transform a primary carbon source into a reliable source of carbon capture and storage. Our research directly addresses this challenge. We recognized the need for a comprehensive evaluation of the various proposed carbon capture, utilization, and storage (CCUS) technologies for concrete. The goal was to go beyond individual technology studies and develop a comparative framework to identify the most practical and effective decarbonization pathways for the industry.
To build this framework, we surveyed the current landscape, focusing specifically on emerging or less-conventional technologies that have not been widely discussed. We looked for these approaches across academic papers, recent patents, and industry reports. We identified nine distinct CCUS approaches and grouped them into three main categories to facilitate a more comprehensive comparison of their fundamentals: direct mineral sequestration (e.g., carbonating olivine), bio-based additives (e.g., pre-treated biochar or microalgae), and engineered systems (e.g., including electrochemical processes or the use of carbonated water in the mix). Each pathway was then evaluated against a set of critical metrics for industrial transition: What is its actual CO₂ sequestration efficiency? How does it impact the concrete's mechanical strength and long-term durability? And, what are the barriers to scalability and energy efficiency?
Our analysis suggests a complex, yet not insurmountable, trade-off between sequestration potential and performance. There isn't one perfect solution. For instance, we found that integrating washout-pretreated biochar presents a compelling middle ground. It offers a substantial carbon uptake (around 150-200 kg of CO₂ per cubic meter) while maintaining a compressive strength (27.6 MPa) that is viable for many typical structural applications. This suggests a feasible route for near-term industrial mitigation. Other approaches, such as those involving enzymatic biomineralization, resulted in stronger concrete but had a much lower ceiling for carbon removal, making them less impactful from a pure decarbonization standpoint.
The key takeaway from our work is that a single, perfect solution for decarbonizing concrete probably doesn't exist. Instead, the most effective strategy for sectoral mitigation will likely involve a portfolio of solutions. This could mean combining partial cement substitution with the targeted use of different CCUS admixtures depending on the specific performance requirements. For this to happen, however, it requires more than just materials science; it demands a supportive policy environment that can de-risk investment and help scale up supply chains for things like certified biochar. Our findings provide a roadmap that can inform both industrial strategy and policy-making, highlighting how a coordinated approach can help the construction sector not only meet but exceed its mitigation targets, turning our built environment into a key asset in the fight against climate change.
Keywords: Sectoral Decarbonization; Climate Mitigation; Carbon Capture Utilization and Storage (CCUS); Sustainable Construction; Carbon-Negative Concrete.
