Abstract Manager

It is widely accepted that the concentration of CO₂ in Earth’s atmosphere must be limited to limit the rate of climate change.  Regardless of carbon reduction advancements that have been made in recent years, atmospheric concentrations of CO₂ continue to increase and will soon reach unacceptable levels unless measures are undertaken to capture and sequester many gigatons of CO2₂ annually.

More concrete is produced each year than any other human made material.  Worldwide, over ten billion tons of concrete are annulally produced, which is more than a ton of concrete for every person on Earth.  The manufacturing of Portland cement, the key ingredient in concrete, accounts for approximately 8% of global CO₂ emissions.

Many strategies can be implemented to reduce the impact of concrete on climate change, including sequestration of CO₂ in concrete. Concrete structures are enormous reservoirs for permanent storage of massive quantities of captured CO₂ caused by human activities.

Establishment of a common baseline for quantification of the embodied carbon of concrete mixtures is needed. A traditional life cycle carbon assessment (LCCA) for every mix of concrete is rarely performed or available to owners,designers, or contractors.  Development of EPDs for concrete mixes is infrequently undertaken as concrete mix proportions are continually being optimized to account for variability inherent to concrete performance and production as well as frequent changes to materials sources. The carbon intensity of the individual components of concrete (cement, fly ash, slag, sand, gravel, admixtures, etc.) can be known. Accordingly, a LCCA can be produced for each; however, there is currently no universal and accurate methodology for calculating the carbon intensity of various concrete mixes to facilitate comparison.

The presentation will present an overview of work in progress by WSP for the quantification and comparison of concrete mixes for  design of lower embodied carbon structures which will be used by WSP clients and project stakeholders for concrete procurement decisions. The work has developed a straightforward means of providing each concrete mixture with a readily calculated embodied carbon value that directly corresponds to the net sequestered CO₂ and emitted CO₂ for each unique concrete mix. The quantification process is future ready and adaptable for the emergence of new materials and innovative technologies.

WSP currently has ongoing project work for development of the procurement strategy for low carbon intensity concrete mixtures for major projects for federal government infrastructure as well as other Canadian provincial government agencies.