Port Authority NYNJ caps carbon factor in concrete mix designs
Sources: Port Authority of New York and New Jersey; CP staff
Infrastructure and building project concrete schedules for the United States’ top local agency will soon reflect maximum carbon dioxide emissions limits—equivalent to a 25 percent or greater reduction in portland cement content—plus portland limestone cement and ground glass pozzolans allowances. The new CO2 threshold and conditional binder specifications are the latest measures in a three-year old Port Authority of New York and New Jersey program geared to “dramatically reduce the embodied carbon of concrete mixes approved for use in agency projects” and abide a commitment to achieving net-zero emissions by 2050.
Two years of testing and analysis have positioned the Port Authority to identify 18 concrete mix designs that can reduce emissions by up to 37 percent when measured against currently approved low carbon concretes. “This is a true win-win, achieving better environmental outcomes while maintaining our high standards for concrete performance and safety,” says Executive Director Rick Cotton. “The update of our concrete technical requirements is a milestone as we continue aggressive efforts to drive down the embodied carbon of major building materials.”
The revised concrete specifications have evolved through internal and external channels. The latter include work with faculty and students at New York University, New Jersey Institute of Technology and two Garden State neighbors, Princeton University and Rutgers University. “The Port Authority is committed to researching sustainable practices for our infrastructure to improve the quality of life for communities we serve,” affirms Chairman Kevin O’Toole. “We are proud to partner with students and faculty in initiating change towards a cleaner future.”
The agency will soon enter the final phase of research into even more sustainable concrete, he adds, testing the performance select mixes at Port Authority facilities. The agency and academic partners plan to disseminate pilot program findings to ensure that other entities across the country can incorporate such research into their own practices.