CemWeek looks into the green construction landscape and explores the role of the cement industry in shifting the conversation away from cost by creating a virtuous cycle
As society has begun to see the initial calamitous aftereffects of climate change as predicted by legions of scientist for decades, there has been a concerted but ill-organized scramble to cut emissions across industrial and economic activities on a large scale. The construction industry, in particular, is coming under increased scrutiny, with resource- and emission-heavy cement and concrete coming first in a long list of concerns to address.
Cement manufacturing is one of the industries that contributes the most to greenhouse gas emissions, about eight percent of the annual total, according to Chatham House, the Royal Institute of International Affairs, an independent policy institute based in London. Nevertheless, the building material is also one of our most used resources, second only to water. With a rising global population, the need for resilient housing and infrastructure in the wake of increasingly temperamental weather due to climate change is ever more pressing. But what to do when the solution is also a large part of the problem?
While some alternative materials to cement exist, their cost, durability or performance efficiency when compared to the material still fall short of the widely available construction product. And while certain manufacturing and mixing techniques or equipment are used to minimize the impact of its production on our atmosphere, they may not be the most accessible, either monetarily or logistically, in the developing markets, which account for a larger share of the global production.
Source: CW Research
However, according to many companies, customers are still slow to embrace the new products, due to “limited sensitivity for carbon emissions in the construction of a building,” according to Jens Diebold, head of sustainability at LafargeHolcim. Diebold stressed that the company had once launched a carbon-free product, but customers did not show much interest as it was more expensive and used a different production process.
The industry is nonetheless now more aware of these problems and is continuously working to reduce their impact on climate and carbon emissions through more sustainable practices, innovation, and research. It is estimated that the use of clinker alternatives and of other cementitious materials could help to cut emissions of greenhouse gases by 25 to 35 percent, while the use of waste materials in concrete manufacturing could also enable power and material savings for the industry.
New methods, new equipment
In its 2018 Sustainability Report, LafargeHolcim highlighted how it has been able to slash its net carbon emissions per ton by 25 percent since 1990, increase processing of waste at its mills by six percent when compared to 2017, and reduce overall water withdrawal at its plants by 7.5 percent. While these efforts are commendable, especially for one of the largest global cement producers, they may do little to meet the Paris Agreement goals of “keeping a global temperature rise this century well below 2 degrees Celsius above pre-industrial levels and to pursue efforts to limit the temperature increase even further to 1.5 degrees Celsius”, according to the United Nations. That is because cement production facilities are mostly located in countries or regions with fewer emission regulations, and smaller companies may not be able to invest in equipment or projects to reduce their impact on the environment.
However, breakthroughs in research for new production methods and materials could make construction materials, cement in particular, more environmentally-friendly. A particularly recent development has garnered interest in the industry, as researchers from the Massachusetts Institute of Technology (MIT) have created a new production method for cement using electrolysis that removes all carbon emissions in the process, and also allows for reuse or sale of the resources utilized in the process.
Source: CW Research
One of the most important ways to achieve a greener product is also to reduce the amount of non-renewable resources utilized during the manufacturing process, or to use alternative materials. Co-incineration in particular has become the industry’s go-to solution for this challenge, as it allows the processing of waste – with used rubber tires being one of the most used materials – into fine cement powder, replacing clinker and offsetting some of the production process impacts. Other solutions are also popular, particularly in the concrete-making phase, and include replacing part of the cement mix with fly ash, or aggregates such as sand with microplastics or other types of waste, even construction waste.
India was one of the leaders in mixing waste during concrete production, as well as in the overall cement production process. In the 1996-1997 fiscal year, the country introduced new regulations to tackle the growing fly ash piles at the new coal-powered power plants, which sprouted from the government’s efforts to industrialize and modernize over several decades. Among the top uses directed for this waste material from coal burning was cement and concrete production, with fly ash being blended with both materials during their respective manufacturing phase without compromising the performance of the final product.
The initiative boosted much research into fly ash and other waste products, such as granulated slag, a byproduct from the steelmaking process, all over the world. Scientists have also begun looking into materials such as plastic polymers to mix with cement instead of aggregates and sand to produce concrete, as well as construction waste, thus reducing the impact of the final product on the environment.
Furthermore, the main contribution of concrete to the green trend lies in its capacity to reabsorb part of the carbon it emits into the atmosphere during its making, known as recarbonation. Many in the industry have started to look at this as their starting point to develop carbon-neutral policies and/or carbon capture and storage (CCS) projects, such as HeidelbergCement, which is researching the feasibility of its full-scale carbon capture and storage project at its subsidiary’s, Lehigh Cement, Canadian facility. HeidelbergCement has also recently signed a memorandum of understanding with Norwegian energy group Equinor to expand its CCS projects in the region, as well as its transportation and use. Meanwhile, LafargeHolcim has also focused on carbon capture in Canada, partnering with the CO2MENT project to capture and reuse CO2 from its cement plant in Richmond, British Columbia.
In addition to already-established cement manufacturers’ CCS undertakings, initiatives such as Australia’s Mineral Carbonation International (MCI) seek to transform CO2 emissions into valuable products for use in advanced materials and in building products such as cements and plasterboards. In July 2018, MCI completed a five- year research pilot plant program funded by Australian Governments and Industry. Currently, with solid techno/economic validation of the technology, the company is developing partnerships and investment for global commercial opportunities.
“What these developments and initiatives have shown is that environmental challenges are not limited to a particular set of countries, but rather require a global approach,” notes Prashant Singh, CW Group’s Associate Director.
“However, sustainability issues are in effect more of a concern to emerging and developing economies, which need to push for immediate and large-scale adoption of these products and policies to mitigate the impact that climate change is likely to have on the most vulnerable populations,” Singh adds.
Demand for green solutions in the construction industry is growing steadily, particularly in developed markets, where consumer awareness regarding these issues is stronger. As policy makers at a global scale are enforcing more sustainable practices in line with goals set forth by international movements, the appetite for green construction materials and production methods is only expected to intensify over the coming years. Therefore, companies are expected to ramp up their research and development on the topic, with many of them already offering “green cement” products in key markets, such as Votorantim’s Verdera brand, which offers co-processing services to Brazil’s industry, and LafargeHolcim’s wide range of green cement products, including CEMII, LEED, BREEAM, and HQE, used across many markets according to its clients’ needs.
“Despite the above, the main challenge in front of the industry is the fact this debate has been framed as a push-pull conversation rather than a pull-push approach,” assesses Singh. “In essence, the industry needs to help change the paradigm of how its customers see its products, and this will then push for more changes, leading to a virtuous cycle. As long as consumers do not purchase these products, their concerns driven primarily by a pricing approach, all the new substitutes and products are of little use. The conversation needs to change from why consumers should use these products to why they need to, with costs a part of the conversation, not the defining quotient.”
With human impact on climate change a constant topic both for discussion and action, the industry is under scrutiny to change its practices. There still is a long way before the road to green construction evolves from what is still perceived as a niche into a widespread cornerstone of contemporary and future quality of life. However, policy makers are also under pressure to promote transformation, which could come sooner rather than later as grassroots movements and consumers’ increased awareness of their influence on the industry and its products are better understood.
This article originally appeared on CemWeek Magazine #52