Formwork which is constructed out of knitted wool may emerge as an eco-friendly alternative to traditional construction formwork if new research proves to be successful.

Researchers are experimenting with wool forms to create formwork that is used to construct concrete columns.

The product will be an alternative to traditional formwork which is constructed of metal, timber and fibreglass.

According to the researchers, regular formwork is often discarded as construction waste after a single use.

However, formwork that is constructed out of wool can be reused up to three times (it is washed in cold water between uses).

The woollen formwork is also biodegradable and can be constructed from recycled wool that may otherwise been destined for landfill.

The latest research comes as the building industry is under pressure to reduce the volume of waste which is being generated in construction and ending up in landfill.

In 2020/21, Australia’s construction and demolition sector produced 25.2 million tonnes (MT) of waste, according to the 2022 edition of the National Waste Report.

This accounts for roughly one third of the overall volume of waste that was produced throughout the nation in that year.

(Left: Wool formwork before the pour. Centre: the resulting concrete column. Right: Laser-scanning the column.(

The wool forms that have been created in the research were produced by Professor Paul Loh, head of the Abedian School of Architecture at Bond University along with RMIT lecturer Dr Jenny Underwood and David Leggett, a partner at Melbourne based architecture and design firm LLDS.

Through the research project, an advanced knitting machine used Australian wool to produce sock-like seamless forms.

There were then suspended by an industrial robotic arm as concrete was poured in.

The largest of the test columns was 1.8m high by 17.5cm wide.

According to Loh, fabric formwork has in fact been used since the 19th century.

Thus far, however, its application has been limited by the unpredictable shapes produced during casting.

“Typically, woven fabric is used which is also restrictive in its shape and requires tailoring skills,” he added.

“The use of 3D-knitted fabric has never been explored to its full capacity in this application, and the research sets out to explore the feasibility of casting using bio-material such as wool and testing the repeatability of the cast using a single mould.”

In order to be used in construction, Loh says the columns will need to be scaled up to twice the height and width of the current forms that have been created.

The forms will also need to be uniform in shape.

“While the fabric naturally produces a different and almost novel aesthetic in the cast, the research aims to find the correlation between the knit architecture and the resulting cast geometry,” he said.

“Our research has so far only produced a feasibility study, and our next step is to delve deeper into the computational code behind the 3D-knit fabric to align it with the shape and structural performance.”

Speaking at a broader level, Loh says the construction industry needs to change its ways in order to reduce the volume of waste that ends up in landfill.

“More so than ever, we need to re-examine our construction practices against the three principles of circular design: eliminate construction waste, circulate products for long-term use and regenerate natural systems by using biodegradable material,” he said.

The research was funded by the University of Melbourne.

 

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