Large-scale concrete and steel structures have become potent symbols for human development. But the paradox of modern construction is that by shaping the environment to be hospitable to our needs, it has also contributed towards making the planet a much more dangerous place to live.
Steel and concrete, the world’s top two building materials, together contribute around 12 percent of global emissions – roughly as much as the oil and gas industry does.
The construction industry must rapidly find alternatives to the current material mix and an unexpected alternative may be bamboo. As a hollow, tubular grass, it seems an unlikely candidate to replace concrete and steel in modern buildings. However, studies show its tensile strength is similar to that of steel. When combined with other biomass and additives, it can form composites that approach mined materials configurations for strength and durability.
Another advantage of bamboo is that it grows very quickly, meaning that it can be logged every two years while other species require longer to mature. The high growth rate means it has the potential to provide structural fibre at a rate of five to six times faster than wood.
Green shoots: new startups bringing bamboo to building projects
Two very young companies are leading the way in bringing bamboo structural components to the construction industry. Hemboo, founded in 2020, is an early stage Danish startup proving that this ancient building material can hold its own in the construction sector. Their product is a prefabricated wall panel made from a blend of hemp and bamboo, which the company claims can replace concrete and mineral wool for even large-scale projects.
Like many bio-business, one of Hemboo’s biggest challenges is ensuring that clients can make the switch to unfamiliar products at minimal cost. To ease the transition, the company builds their bamboo walls so they can slot into existing prefabrication and installation methods. Fitted to project specifications before being transported to the construction site, they are ready to be joined to other building parts as soon as they arrive.
Widuz, a Singaporean startup founded in 2019, is also bringing modified bamboo to market. Its flagship product is Bamboo Veneer Lumber, which can go into anything from structural beams and walls to skateboards and skis. This is a composite that blends bamboo with resin, resulting in a material that is 3 times stronger than timber. The resin additive reduces the decay common in woody biomaterials.
BamCore’s carbon-neutral bamboo
Bamboo’s big sustainability sell is that it can lay claim to being carbon negative. This is one better than carbon neutrality. It means that over the entire life of the product from felling to processing, the bamboo absorbs more carbon from the atmosphere than it releases.
Peer-reviewed studies into the carbon negative potential of bamboo are still limited but one was published in 2019 that calculated that over the whole production process including transport, production and packing, a particular bamboo flooring brand came out to a -14.89kg carbon footprint.
This was based on estimates that the plant absorbed 267.54 kg of carbon dioxide as it grew. Emissions from the industrial processes that turned it into a product were 14.89 kg less than this figure.
BamCore was founded in 2008, making them one of the older bamboo building materials companies. Their leading product is the BamCore Prime wall which they claim is the first carbon negative structural framing material on the market. The hybrid lumber combines eucalyptus and other woods that optimises for heat efficiency and insulation. Eucalyptus is another wood famous for efficiently storing carbon.
Unusually for a bamboo materials company, BamCore also offers a product specifically for use in mid- to high-rise buildings – the Mass Timber Bamboo, which is designed to cut concrete use in large-scale projects.
Building strength does not just depend on the physical properties of construction materials. The way that components are fitted together is another facet of making durable structures. BamCore uses a ‘Load Optimised Biogenic Industrialised Construction’ method for low-rise buildings. It allows planners to decide exactly where structural panels made from BamCore’s different bamboo-based materials should be placed.
Currently, Bamcore’s uses a 40% / 60% bamboo to wood mix in their hybrid materials but are working on upping the bamboo content further. In 2023, the company was awarded $2,30,060 by the US Advanced Research Projects Agency-Energy (ARPA-E) to advance a 90+% bamboo content hollow wall system for constructing carbon negative low to mid rise buildings.
Bamboo in infrastructure
Historically, bamboo has not just been used for buildings but for infrastructure too. In China, archaeologists have found natural gas transportation pipes dating from 400 BC made from bamboo wrapped in waxed fabrics.
Bamboo may be returning to large-scale public infrastructure now that the Chinese government’s latest five year economic plan earmarked the bamboo composite sector as one to support.
The objective is to develop and scale cost-effective bamboo-based materials for urban projects like pipes as China tries to maintain economic growth while setting its industries on a renewable footing.
China’s official interest in bamboo will be a windfall for domestic companies like Bamboo-based Composites Technology Co. that has been selling bamboo products for irrigation, drainage, and sewage systems since the mid-2000s. They now plan to make materials for railway carriages, storage tanks, and houses.
Western interest in bamboo infrastructure still lags far behind but researchers at the University of California Davis may change this with their mycelium-bamboo composite for wind turbines.
The material is designed to replace balsa wood and fibreglass in wind turbines, which are notoriously difficult to recycle. In June 2023, they will test their renewable materials out on a commercial 1-kilowatt turbine set up near an energy research centre in Davis.
The one drawback of bamboo in infrastructure is that in its natural form, the fibres absorb water which speeds degradation and structural weakening. However, researchers at the University of British Columbia, supported by NetZero Enterprises, have discovered that dehydrating bamboo within biocomposites can reduce moisture uptake. The invention could extend the material into further heavy duty applications.
Bamboo biocomposites have proven uses in carbon mitigation but it could also be a tool in climate adaptation. With extreme weather set to become the norm, the ability to construct infrastructure rapidly from readily available bio-materials will be a massive advantage to urban authorities and NGOs.
Already, bamboo has been used by the Red Cross to build post-disaster building shelters for its strength, versatility, and abundance. But its uses in more permanent structures are becoming apparent. In Bangladesh, the Mayalansian company edotco and the Bangladesh University of Engineering constructed a 100% bamboo cell tower in the Bangladeshi capital. It took 12 days to build and can withstand winds of up to 130 mph, with an expected lifespan of 10 years.
Sustainable scaling
Modern buildings are among the most materially intensive technologies that we rely on. However, the importance of the construction industry means that it presents an enormous strategic opportunity for the bio-based sector. This opportunity is both a financial one but also a wider societal one, in terms of offering a space in which bio-businesses could quickly become a key actor in laying the foundations of a sustainable economy.
At the same time, conscious effort has to be made to construct a viable but sustainable bamboo value chain.
Bamboo’s carbon negative potential stems from how quickly it grows as well as the fact that it requires relatively little need for pesticides or fertilisers. However, the overall environmental impacts of bamboo products do not flow automatically. It depends heavily on the way industrial-scale plantations are set up.
Scaling always entails ecological costs and keeping these impacts to a minimum means making strategic choices about where to plant feedstock crops. For example, bamboo plantations must not replace land formerly rich in biodiversity and carbon-sequestering potential, which could eat into its climate mitigation benefits.
Although expanded bamboo production could easily pose ecological problems, the supply chain could also become part of regenerative forestry projects. This is because bamboo can easily coexist with other plants, opening the potential to set up diverse plots that harbour many different kinds of species and limiting the ecosystem impacts of higher industrial demand. Bamboo plantations could also help restore land destroyed by flood or deforestation.
New bamboo biocomposite value chains must be carefully planned in order to realise the sustainability potential of the industry. Policymakers need to work with industry on where and how best to boost volumes of bamboo feedstock in ways that enhance its ability to serve carbon mitigation and ecological goals at each step of the supply chain.
