A Complex Landscape – Part 1/2
Innovations in building materials are far from being a straightforward topic. In the architectural, construction, and engineering industries, the adoption of new materials and construction solutions varies greatly across different building elements. Some construction materials have been in use for decades, if not centuries, without significant changes, while the market for finishing materials, on the other hand, is more flexible and open to innovations, regardless of technical or economic reasons.
In the World of Innovative Building Materials
In the realm of innovative materials, low-emission options have emerged as key players in today’s industry. Regulations such as the new European Taxonomy & EBPD (European Commission & Joint Research Centre., 2019) have begun to mandate carbon dioxide emissions reporting throughout the entire life cycle of assets. This means that investors must understand the impact of their material choices not only during a building’s operational phase but also before the material even arrives at the construction site. The method behind these calculations is life cycle analysis, with a key metric being a material’s potential to contribute to the greenhouse effect, commonly referred to simply as carbon.
This is where materials of biological origin come into play—those derived from plants, such as wood, tree bark, cellulose fibers, or even from fungi used for thermal insulation boards for example (Berge, 2009). Throughout their life cycle, they have the ability to capture carbon from the atmosphere, even if they require industrial processing that reduces this benefit. In the concept of circular life, where we aim to prevent the release of carbon from materials at the end of their life, we can consider both the technical and biological cycles of these materials (Barungart et al., 2008). The technical cycle involves the dismantling of materials and processing for reuse, while the biological cycle considers the possibility of biodegradation, the breakdown of biological materials, and their transformation into nutrients for the growth of new biological materials. This cycle closes at the level of “life,” rather than at a factory.
Certainly, the ideal approach would be to endlessly reuse and recycle materials that have served as sources for construction and are components of existing buildings. However, the majority of these materials have not been designed for longevity or reusability. Many are connected with chemical adhesives or combined in a manner that makes it impossible to grant them a second life. In this article, we will shift our attention to bio-based alternatives—materials that we can integrate into the circular flow of construction materials.
However, materials of biological origin are not the only low-emission solutions. Many traditional construction techniques, dating back to the early 20th century and before, rely on using any material available on the construction site with minimal or zero industrial processing. This typically results in minimal carbon emissions released into the atmosphere. In this article, we discuss innovative materials, their applications, and the challenges associated with them. They are innovative, but that doesn’t always mean they are entirely new. Some of them are traditional solutions that have been displaced by newer, cheaper, and more universal approaches to construction, which often have detrimental effects on the planet and human well-being.
Bio-based materials as an alternative to concrete, steel, and plasterboard.
Today buildings are primarily made of concrete. Although it’s a material known and used since ancient times, it was composed differently back then. The Romans used a mixture of lime mortar and volcanic ash, known as “pulvis puteolanus,” as their cement. Modern concrete composition was improved with the introduction of Portland cement in the early 19th century, and since then, it has become widely popular, largely replacing native materials.
Each year, 4 billion tons of cement are produced, contributing to up to 8 percent of global annual CO2 production (Habert et al., 2020). The most toxic process occurs during the breakdown of limestone and clay into oxides at temperatures of 1400-1500 degrees Celsius, emitting over half of the carbon dioxide emissions associated with cement production.
However, limestone has played a significant role in the development of construction. Natural binders are used, among other things, for the production of mortar and plaster. Ideally, construction materials should be as minimally processed as possible, with low embedded energy. Wooden elements typically fulfill the structural role in a building due to their strength and low carbon footprint. According to Life Cycle Assessment (LCA) studies, hydraulic mortars based on Natural Hydraulic Lime (NHL) contain at least 15 percent less embedded carbon than cement mortars (Brás & Faria, 2017). In the long-term analysis, NHL-based mortars have a significantly smaller impact on the entire building’s lifespan due to the risk of leaching of NHL mortars. Without wood-based structural components, they are not necessarily less emission-intensive than cement mortars.
In the next part of the article, we are going to bring more details on rammed earth and hempcrete. Two bio-based materials with great potential, used on a small scale by cutting-edge architectural practices and vernacular builders. Learning from the past will be a common denominator of some future materials.
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Barungart, Michael., Hoye, Stephen., & McDonough, W. (2008). Cradle to Cradle. Tantor Media;
Berge, B. (2009). The Ecology of Building Materials. Elsevier.
Brás, A., & Faria, P. (2017). Effectiveness of mortars composition on the embodied carbon long-term impact. Energy and Buildings, 154, 523–528. https://doi.org/10.1016/j.enbuild.2017.08.026
European Commission, & Joint Research Centre. (2019). Achieving the cost-effective energy transformation of Europe’s buildings: Combinations of insulation and heating & cooling technologies renovations : methods and data. Publications Office. https://data.europa.eu/doi/10.2760/278207
Habert, G., Miller, S. A., John, V. M., Provis, J. L., Favier, A., Horvath, A., & Scrivener, K. L. (2020). Environmental impacts and decarbonization strategies in the cement and concrete industries. Nature Reviews Earth & Environment, 1(11), 559–573. https://doi.org/10.1038/s43017-020-0093-3
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