The building industry is one of the biggest generators of carbon emissions, with some estimates suggesting that 38% percent of all CO2 emissions are linked to this field. As a response to the current crisis, architects, designers, and researchers are taking measures to reduce their carbon footprint during and after construction. Many initiatives and research teams are looking at building materials to find low-carbon solutions and reduce the impact of building materials during production.
One of the most prominent fields of research is concerned with biofacture, the type of process that involves using biological organisms to manufacture materials. By understanding the abilities of organisms such as algae of fungi, alternatives to widely used materials can become carbon neutral or even carbon negative. Other initiatives are researching novel ways to use untapped, yet readily available resources such as desert sand, soil, or waste from demolitions.
Below, we present ten innovative materials that offer sustainable alternatives to common building materials.
The most common type of cement, Portland cement, is made with quarried limestone, which is burnt at high temperatures. This process accounts for a large part of the material’s greenhouse emissions. To address this problem, researchers from the University of Colorado Boulder have created a biologically grown limestone that could potentially make cement production carbon neutral, or even carbon negative. The idea is inspired by coral reefs, which can grow their own durable structures from calcium carbonate, the main component of limestone. The Living Materials Laboratory at CU Boulder, led by Wil V. Srubar, began to cultivate single-celled algae that, through photosynthesis, can sequester and store CO2 in mineral form. Because the method involves using concrete as we know it, it can already be used in structural applications on a mass scale.
Indus is a bio-integrated wall designed to help developing communities in India treat polluted water. The wall is a living skin made of tiles layered with microalgae get that treat contaminated water as it trickles on its surface. Each tile has a biomimetic pattern inspired by the veins of a leaf, a design adapted to direct water where it is needed most. The tiles can be created on-site using regional materials like clay and laterite. To obtain the pattern, researchers developed 3D-printed molds to be distributed to the communities. Each mold is tailored by the design team, researchers at the Bio-Integrated Design Lab at the Bartlett School of Architecture, UCL, to suit the type of pollutants identified on site.
Ecovative is a company specializing in growing complete structures with mycelium. By upcycling the products of agriculture, these materials have the potential to replace unsustainable products of the building industry. To demonstrate this potential, the company collaborated with The Living studio in New York and ARUP as structural consultants to develop the Hy-Fi pavilion, built as an installation built in the yard of MoMA PS1. The circular tower is constructed with mycelium bricks, developed and grown in less than a week. To produce them, a substrate and fungi are combined in a solution and inserted into molds. After about 5 days of growth in favorable conditions, the material is solidified into the desired shape and stabilized by deactivating the microorganisms.
Karen Kerstin Poulain explores the possibilities of building with soil by proposing a new method of working with it: pouring it. The result is a concrete-like composite that is resistant to compression and cracking. The composite is made from tepetate, water and rice husks are producing it requires little energy input. Besides replacing concrete, an energy-intensive material responsible for eight percent of global CO2 emissions, Karen Kerstin Poulain’s alternative has the added benefit of reducing agricultural waste.
Carbon Craft uses the inevitable byproducts of industries as raw material to fabricate tiles made out of “carbon black”, a waste material that is generated during the combustion of fossil fuels. In the industrial process, this material is discarded or further burnt. The innovative venture led by architect Tejas Sidnal uses technology and craftsmanship to repurpose this byproduct, preventing further combustion and locking it into a decorative element. The tiles are made by shaping, cutting, and mixing carbon black with cement. The craft of cement tile manufacturing has a 200-year-old history. Local artisans were involved in defining the production method. The result is an economically viable product that upcycles waste material and empowers the artisan community.
Cracks and crevices can endanger the mechanical qualities of concrete by allowing water to penetrate the material. TU Delft is developing a prototype of concrete that can regenerate and heal its hairline fractures due to the addition of bacteria in its composition. Added into the concrete from the beginning, the water-activated bacteria would feed on calcium lactate provided in the mix and produce limestone, a material that would patch up small holes and cracks in the concrete.
Mycelium-based materials are carbon-negative and compostable materials grown by combining mycelium and organic by-products. Myco-materials can potentially replace plastics and problematic composites while valorizing other industries’ leftovers. Myceen is a research and design entity focused on developing this technology. They are focused on exploring the qualities of mycelium materials and applying them to create interior products such as acoustic panels or furniture. In addition to being cost-effective and biodegradable, these materials also have high acoustic absorption, low thermal conductivity, and high fire resistance.
The type of sand regularly used in construction is one of the most extracted solid materials in the world, making sand depletion a global issue. Desert sand is a readily available resource, but it is unusable in regular concrete, as the grains are too smooth to bind together. Finite is a material developed by post-graduate students Carolyn Tam, Hamza Oza, Matteo Maccario, and Saki Maruyama at the Imperial College London. It is a composite material created with organic binders and desert sand rather than beach sand. Due to its material properties, Finite can be remolded for multiple lifecycle uses.
“Breathe Bricks” are an effective alternative to conventional bricks, developed by Ar. Carmen Trudell, an assistant professor at Cal Poly San Luis Obispo’s School of Architecture. These bricks follow the principle of air filtration inspired by “cyclone filtration” used in vacuum cleaners. They separate the pollutants and dust in the air and transfer them to the interior of the material. The bricks are shaped as porous concrete blocks with interior shafts. The faceted design helps direct airflow inside the unit.
Mineral wool is a fibrous material formed by the spinning or extracting of minerals or molten rocks, such as slag and ceramics. After demolition, this voluminous material ends up in landfills. The WOOL2LOOP project aims to use mineral wool waste in products such as façade panels, and acoustic sheets, exploring the material’s potential for circularity. The process starts by separating mineral wool residues, grinding them, and using them as products through alkaline activation, also known as geopolymerization. This results in a ceramic or concrete-like material. Geopolymers are considered good alternatives for traditional Portland cement (OPC), mainly due to comparable mechanical properties, while releasing a fraction of the carbon dioxide.
This article is part of the ArchDaily Topics: The Future of Construction Materials. Every month we explore a topic in-depth through articles, interviews, news, and projects. Learn more about our ArchDaily topics. As always, at ArchDaily we welcome the contributions of our readers; if you want to submit an article or project, contact us.
Editor's Note: This article was originally published on September 01, 2022.