Legislators in New York and New Jersey are considering bills that would promote the use of low-carbon concrete on state projects.
Both legislative houses in New York have approved a measure that would require the Office of General Services to set guidelines sourcing concrete with lower embodied carbon for state contracts. Contractors would be mandated to follow the guidelines and certify that the concrete they use is in compliance.
In New Jersey, the legislature is deliberating a bill that would establish a discount rate for contractors using low-carbon concrete when they submit bids for state projects. The bidding advantage would be based on the global warming potential values for concrete. The discount could be as much as 8% of the total cost of the project.
The production of cement is estimated to be responsible for as much as 7% of total global carbon emissions. Cement manufacturers have developed portland-limestone cement, a blend with higher limestone content and lower carbon. Another lower carbon manufacturing process uses fly ash to replace as much as 50% of the portland cement in concrete. A third alternative involves injecting carbon dioxide into ready-mix concrete at the batch plant.