Can we save the planet by replacing steel with microwaved bamboo?

Posted by Derek Mason

22nd December 2020

Photo credit: Eleonora Albasi on Unsplash

In the not-too-distant future, skyscrapers, cars and aeroplanes could be built from microwaved bamboo. It sounds far-fetched, but scientists have been looking at how to strengthen bamboo. And they’ve come up with a unique method that involves microwaving the fast-growing plant to improve its mechanical properties.

Bamboo is already used in construction. Its relatively low cost has led to it being used to build flood resistant houses in Vietnam, homes for earthquake victims in Nepal and temporary accommodation for Burmese refugees in Thailand.

A clear advantage of the substance is that it is more sustainable than the popular options of steel, concrete and brick. If those materials are used less, this will reduce greenhouse gas emissions – a key part in tackling climate change.

But bamboo in its natural state is flawed. Although it has high tensile strength, it also has a high water content. Untreated bamboo is prone to attack by insects, and long-term durability can be an issue. This is where microwaving comes in.

Scientists have developed a two-step manufacturing process that drives water out of the bamboo, leading to a significant volume reduction of 28.9%. Despite this large reduction, the bamboo’s structural integrity is maintained.

The two-step process is as follows:

  1. The bamboo undergoes partial delignification (chemical treatment to extract lignin), making the cell walls of the bamboo softer.
  2. The bamboo is then heated evenly using microwaves. This almost doubles tensile strength, enhances toughness by 3.2 times, and doubles bending strength compared with natural bamboo.

After this process, the modified bamboo is able to outperform steel in terms of tensile strength. Since this is a rapidly and easily scalable process, and the bamboo is a readily available resource, this makes the material a strong, lightweight option in construction.

While we are likely to be some way off from using this material in our buildings in the UK, it’s reassuring to note that so many scientists are working to come up with renewable resources that have practical applications.

With governments and the construction industry as a whole all committed to net zero carbon by 2050, and some more ambitious firms like Barrett Developments with 2040 in their sights, we will all need to be open to new methods for reducing our footprint, and encouraging our clients to do the same. Especially since 10% of emissions in the UK are estimated to be directly associated with the construction industry.

Meanwhile, if you need assistance with the structural elements of an upcoming project – with or without microwaved bamboo – please do get in touch.

We would like to wish you all a very Merry Christmas and a Happy New Year, despite the difficult restrictions.

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