PFI-TT: Bio-inspired enhancement of concrete for carbon sequestration and longevity

The broader impact of this Partnerships for Innovation - Technology Translation (PFI-TT) project is to develop novel bio-inspired additives that will enhance carbon sequestration, mechanical performance, and the longevity of concrete. Ordinary Portland Cement (OPC) is one of the most energy-intensive manufacturing industries in the U.S. and is responsible for nearly 8% of global anthropogenic carbon emissions. Due to the high carbon footprint of OPC, a variety of alternative low-carbon cementitious materials have been developed in the past decade, many of which rely on carbon dioxide (CO2) curing. However, the potential chemical admixtures, that can enable controlling the performances of this new generation of CO2-cured concrete have not been well-explored yet, primarily due to the lack of understanding of the hardening mechanism of these materials. This project focuses on designing and resolving the upscaling challenges of bio-inspired additives specifically formulated for CO2-cured concrete. The bio-inspired additives will improve the functionality of CO2-cured concrete and therefore, expand the application sector for such low-carbon technologies. The application of such low-carbon technologies will enable the U.S. government’s goal of reaching Net Zero emissions by 2050. The proposed project aims to upscale and evaluate the commercialization potential of bio-inspired additives via following four tasks: (i) evaluate the compatibility of bio-inspired additives with traditional chemical admixtures that are typically used to control different performances of concrete, (ii) investigate the effectiveness of bio-inspired additives at different length scales and environmental conditions with variable CO2 concentration levels, (iii) investigate the durability performances of concrete prepared using bio-inspired additives, and (iv) perform environmental impact assessment and techno-economic assessment of producing and using bio-inspired additives in the production of carbonation cured cementitious composites. Calcium carbonate (CaCO3) mineral is the primary binding phase that controls the strength as well as the CO2 sequestration capacity of carbonation-cured cementitious composites. A series of bio-inspired additives were found to be able to control the CaCO3 precipitation and polymorph conversion kinetics in carbonation-cured cementitious composites. By doing so, these additives can enhance the mechanical performance, CO2 sequestration capacity, and durability of carbonation-cured cementitious composites. To mitigate the potential risks of upscaling and commercialization of these bio-inspired additives, their performance and cost-effectiveness for different cementitious material systems, length scales, and environmental conditions will be evaluated in this project. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.