Farshid Bonakdar is a Principal Engineering Consultant at RSK Group’s Materials and Structures company
The high carbon footprint of Portland cement means that finding alternatives remains a priority. However, the high durability and flexible workability of Portland cement-based concrete present a considerable challenge for the immediate future.
Given the challenge of finding a suitable substitute for cement, along with efforts to reduce CO2 emissions from cement manufacturing (according to the United Nations Economic Commission for Europe, the cement industry alone was responsible for nearly 7 percent of global emissions), we must also take a scientific approach to how we build.
“We need to carefully consider whether new construction is really necessary”
We need to carefully consider whether new construction is really necessary and whether concrete is the only suitable material for the job. If so, what are the options to reduce or eliminate the portland cement content? In addition, honest consideration should be given to exploring options for the rehabilitation or restoration of existing buildings.
Restoration and reconditioning
Where we can, we should restore, retrofit and reuse existing structures, maximizing creativity and architectural innovation. Following the methodologies described in ISO 14067:2013, whole life cycle carbon analyzes can be implemented to provide scientific and evidence-based answers to these questions, with the aim of reducing greenhouse gas (GHG) emissions.
However, from a wider sustainability point of view, it is essential to consider the life cycle assessment of any built environment which must be carried out in accordance with the recommendations outlined in ISO 14044, to fully understand all the potential environmental impacts of our activities, whether we are building new or changing the use of existing structures.
Life cycle assessment is a methodology for assessing the environmental impacts (such as GHG emissions) associated with all stages of a product or structure’s life cycle. A reliable life cycle assessment includes all upstream and downstream processes specifically associated with the product throughout its entire useful life. In the built environment, this means everything from the extraction and processing of raw materials, through the manufacture, distribution, use and maintenance of the product, to the practicable end-of-life scenarios that could be conservatively considered, be it replacement, disposal, reuse or recycling.
Be specific to the project in the evaluation
Each of these elements requires the input of specialists in relevant disciplines, such as structural engineers, materials specialists and energy assessors, to acquire data on potential alternatives that could be considered and can satisfy the technical criteria. The result is a project-specific life-cycle assessment with a set of data related to a specific system in a specific location, taking into account the specific materials, suppliers and construction processes for all alternatives in order to select the one most compatible with the full-life carbon and performance objectives.
Unfortunately, these tools are not always used as they should be, and were originally intended to serve policy makers and decision makers. Due to the large number of parameters that contribute to a product’s lifetime carbon footprint and the complex interrelated nature of systems within the product life cycle, commercial shortcuts have become readily available. Universal life cycle assessment inventories that provide initial data to perform the necessary calculations during a product or system assessment have gained great popularity among practitioners and environmental professionals because they provide simple and quick answers to such a complex problem.
Life cycle assessments and carbon footprints are powerful tools that can help us in this difficult period, but only if they are fed with the right information.
Beware of the easy checkbox fix
For many, it is too much to consider, so despite its built-in power and potential, life cycle assessment has sometimes been left as a luxury approach that appears in certain projects, mainly for marketing purposes. This runs the risk of analytics being practiced using preset universal datasets for quick and easy numbers, to tick boxes rather than being used to make strategic decisions.
Just as we realized that without a legally supported design code, our built environments could not provide an adequate, safe and secure asset for a 21St human century, we must also recognize the equal importance of choosing construction techniques, materials and development plans that minimize environmental impacts and ensure the immediate implementation of this crucial aspect in construction practices.
To get to this point, society and governments need to see professionals, practitioners, asset owners and developers acting as role models, performing life cycle assessment during critical decision-making phases. Governments around the world need to see us interested and committed to the most sustainable solutions. The more this approach can be properly demonstrated in meaningful projects, the more important it is that it is legally applied, ultimately creating its own cradle to move forward with sufficient workable arguments.
