Increasing Concrete Strength using Biochar-derived Graphene Products for Reduction of Embodied Carbon

Concrete is the most widely used human-made substance on the planet. Production of Portland cement, a major component of concrete, produces large amounts of CO2 and is the reason the concrete industry contributes 8% of global CO2 emissions. These emissions result in high embodied carbon for construction projects. A potential route to lowering embodied carbon is to reduce the overall amount of concrete needed for projects by improving its strength. A promising method for increasing concrete strength is the addition of graphene oxide, which even at concentrations as low as 0.05 wt% of cement, has shown compressive and flexural strength improvements of over 20% and 50% respectively. This is due in part to the chemistry of the graphene oxide which improves adhesion, but also the morphology which offers structural support within the cement matrix. In the U.S. alone, a 20% reduction in concrete usage would equate to 13.4 million metric tons of CO2 avoided annually, but the barrier against widespread adoption of graphene oxide to achieve this has historically been cost. Graphene oxide is typically a high-cost product, used in specialized applications and in small volumes. It is often produced using graphite, which has no domestic production, and is made using an expensive process and multiple harsh reagents. This project will utilize a newly developed, low-cost method to produce graphene oxide products from biochar, which is produced from wood waste, a plentiful and renewable resource that is also a carbon sink. The patented synthesis method, developed at the University of Wyoming, uses a single reagent to convert chars to graphene oxide products. In addition, the reagent is more environmentally friendly and has high recoverability and reusability. Preliminary work using graphene oxide in concrete has been performed using this method with coal char, yielding promising results, but the use of biochar is a cleaner alternative. Therefore, this Phase I project is crucial for demonstrating proof of concept, feasibility, and commercialization potential of biochar-derived graphene oxide concrete additives. The concrete market is vast with a global value of over $617 billion and it is predicted to surpass $972 billion by 2030 which offers enormous commercial potential. When the aforementioned technologies are assembled in this project, the result will be demonstration of a low-cost concrete additive, derived from renewable resources, which can add strength, reduce overall material requirements, and lower embodied carbon in construction projects.