Reduction of Embodied Carbon in Concrete via Strength Enhancing Biochar-derived Graphene Products

As the most widely used human-made substance on the planet, concrete is a significant producer of CO2. 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 materials, which have been proven as strength enhancers even at concentrations as low as 0.05 wt% of cement. The chemistry of graphene oxide improves cement hydration, and selected morphology can improve structural characteristics 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 patented, 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 process uses a single reagent to convert chars to graphene oxide products. In addition, the reagent is more environmentally friendly and has high recoverability and recyclability. Previous results showed significant gain in compressive strength of 16.4%, and this project will develop these additives further to improve both compressive and flexural strength. 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.