Sources: National Ready Mixed Concrete Association, Alexandria, Va.; CP staff
Data behind a new NRMCA life cycle assessment report for finished concrete shows how ready mixed producers, through more efficient use of portland cement, have cut the respective carbon footprints of 4,000 psi and 8,000 psi orders by 13 percent and 20 percent since 2014. The association surveyed 155 member producers representing 1,954 ready mixed plants, analyzing data on material throughput and other metrics reflecting net energy consumption in slabs or structures.
“This represents a significant step towards meeting our carbon reduction goal,” says NRMCA Executive Vice President for Structures and Sustainability Lionel Lemay. “Members established sustainability goals to reduce environmental impact early on and are truly leading by example in this very important industry-wide initiative.”
The American Institute of Architects-aligned Architecture 2030 initiative announced the Challenge for Products in 2011, setting a goal for building or construction materials interests to halve their carbon footprint over a two-decade period. NRMCA became one of the first industry groups to adopt the 2030 Challenge in 2012 and, following Architecture 2030 protocol, published its carbon footprint benchmarks in 2014.
Cement optimization underlying the footprint reduction noted in the 2019 benchmark follow up report parallels NRMCA’s promotion of performance-based versus prescriptive specifications for public or private building and nonbuilding construction. Prescriptive specifications tend to drive up carbon intensity by setting minimum cement contents, along with water-cement ratios below thresholds necessary to attain targeted concrete performance.
The latest carbon footprint figures represent averages across the industry. Some NRMCA members realize even better metrics by publishing Product Specific Environmental Product Declarations or incorporating supplementary cementitious materials, low-carbon cements or carbon capture methods for certain projects.
“NRMCA’s commitment to establishing industry baselines and product reporting has accelerated movement toward meeting the 2030 Challenge,” affirms President Michael Philipps. “This is inspiring innovations that hold incredible promise for reducing concrete’s carbon footprint by more than 50 percent today. One growing technology, carbon capture, can even create a net negative carbon footprint in the manufacturing of concrete.”