ReefCem: Low-Carbon Cementitious Materials for Artificial Reefs

This project aims to develop carbon-neutral (or negative) and durable cementitious composites via CO2 sequestration for artificial reef application. A Texas-based small business firm ? The International Consulting Engineers (ICE) will develop funded subcontracts with the University of Texas at Arlington (UT Arlington) and Texas A&M University, Kingsville (TAMUK) to accomplish this project. The majority portion of the work will be performed by the ICE, where they will be responsible for material preparation and testing. Dr. Ashraf at UT Arlington will provide the necessary expertise for the development of durable and carbon-neutral cementitious materials. Dr. Rajib from TAMUK will coordinate small-scale Phase I field testing at Baffin Bay, Texas and assist in securing necessary permits through local authroties. To ensure a coordinated, robust effort targeting potential future Phase II installations and testing, the project team will also form unfunded collaboration with a team of licensed professional engineers from Texas and Louisiana, with expertise on marine structural engineering, coastal aquatic restoration, shoreline protection, underwater monitoring, and remote sensing. Successful execution of the proposed Phase I tasks will lead to the development of a material that can be used to construct durable artificial reefs while also permanently sequestrating a significant volume of CO2 under the sea. Two different CO2 sequestration approaches will be followed: (i) accelerated carbonation curing of cementitious composites and (ii) utilization of solid carbon powders.  Additionally, we will incorporate a high volume of recycled materials (e.g., dredged material, and recycled concrete aggregates) to further reduce the environmental impact of the produced composites. One interesting aspect of CO2-cured cementitious composites is that the primary binding phase of these materials is calcium carbonate. The suitability of this category of material for reef structures has not been explored in the past. However, knowing that the primary building blocks of oyster and coral reefs are also calcium carbonate, the application of our proposed material can offer superior compatibility with those living organisms. Accordingly, the primary goal of this Phase I SBIR project is to evaluate the feasibility of using CO2-sequestering cementitious materials to construct artificial reefs, and create a pathway of commercializing this material for national coastal resilience and defense needs.