Reinventing CEMENT: Carbonation-Enabled Mineralization to Engender Novel Technology
Cement is one of the most important building materials in the world and consequently has become the second most energy intensive industrial sector in the U.S. (after electricity production). Producing one ton of ordinary Portland cement (OPC) requires extremely high temperatures (~2642ºF) typically generated using 60-130 kg of fuel oil and110 kWh of electricity, resulting in one ton of CO2 from the calcination of limestone (CaCO3) alone. Globally, this translates to the consumption of 10–11 exajoules of energy each year (~3% of global energy use) and is responsible for over 7% of global CO2 emissions. There is an urgent need to develop new approaches for producing cementitious materials using less energy and producing lower greenhouse gas emissions.
Project Innovation + Advantages:
The University of Virginia (U.Va.), in collaboration with C-Crete Technologies, is developing a new approach for making cement by leveraging the ways in which certain mineral silicates react with carbon dioxide and water. These reactions produce mineral phases that are much stronger and more stable than commercial cements, thereby reducing CO2 emissions and energy use over time. Chemically, the products of these reactions share more in common with ancient Roman cements than they do with OPC. Because of the temperatures and pressures required to make these materials, the project will initially target the pre-cast structures market, which represents 10-20% of the global cement market. This project's objectives are to identify inexpensive mineral feedstocks and industrial waste materials (e.g., flue gas from coal-fired power production, fly ash, and slag from municipal solid waste incineration) to produce these novel cementitious materials at scale, and optimize their reaction and curing conditions to result in strong, durable pre-cast structures.
U.Va. aims to produce high-performance cements for the manufacture of pre-cast concrete products using a fraction of the energy needed to make conventional cement.
The strength and durability of these carbonated silicate materials far exceeds that of conventional OPC and so there is a large potential to deploy these materials in a variety of harsh environments. By using fundamental chemical pathways, desirable properties, such as low permeability, will be engineered into the materials by design.
By exploiting novel chemical pathways for incorporating waste materials such as fly ash into the synthesis of these materials, they could also cost less, use feedstocks more efficiently and cut down on maintenance and/or replacement, saving energy, CO2 footprint, and materials to produce new concrete. The cements’ lower processing temperatures will save on costs and CO2 emissions.
The precast concrete market has been growing rapidly over the past several years. The development of high performance and low environmental impact materials in this market, the products from this work will have a large potential for scale-up and adoption.