Curving concrete's carbon footprint


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In a bid to reduce waste while achieving great design, researchers have developed an adjustable frame for casting curved concrete panels.

In our quest for beautiful building design, it can be difficult to also achieve a low environmental impact.

Bespoke concrete panels have become increasingly popular as they create distinctive buildings, raising their cultural, commercial and aesthetic value. Iconic examples include the Sydney Opera House, and more recently work by Zaha Hadid Architects and Frank Gehry Architects.

The increased use of computation tools in architectural design has also made it easier for architects and designers to incorporate elements such as complex curved surfaces in their designs.

Reducing construction waste

To create curved panels, a curve mould is produced and the concrete set inside to the desired shape. When the panel is curved in two directions it is known as a double curved panel, which is significantly more difficult to achieve using traditional methods.

Robotic 3D printing and milling processes allow casting of doubly curved concrete panels to reduce construction waste, but typically require a specialist skill in operation and the procedure is significantly time-consuming.

So researchers from the Melbourne School of Design, led by Dr Paul Loh, have developed a re-useable and adjustable mould frame for casting double-curved concrete panels.

“Moulds are typically made from expanded polystyrene foam and are often discarded after use, generating significant construction waste and contributing to the embodied energy – the total energy used to produce a building,” explains Dr Loh.

Parametric Adjustable Mould, or PAM, is the bespoke computer numerically controlled machine developed at the University of Melbourne that allows simple, precise fabrication of elements with any double-curved shape. It uses a flexible, low-cost material that is understood by builders worldwide – reinforced concrete.

“Consisting of a single adjustable mould frame, PAM interprets digital information from a panelised surface to actuate the mould into desired positions for concrete casting. Once cured, the concrete panel is removed from the mould with no immediate waste,” says co-inventor, Mr David Leggett.

Lower cost

Dr Loh explains, “This technology eliminates the need for individually unique mould design in the manufacturing of curved panels, reducing manufacturing waste and improving cost efficiency.

It makes fabricating double-curved construction elements, like cladding, affordable to a wide range of construction projects due to the significantly reduced mechanical part in the system, resulting in a lower capital cost.”

Australia produces 24 million cubic metres of concrete annually, 10 per cent of which is pre-cast concrete. Formwork – the steel, timber or polystyrene mould into which concrete is poured – typically constitutes up to 15 per cent of the weight or approximately 0.9 million tonnes of total waste from concrete usage.

Dr Loh says that PAM is currently designed to produce non-structural panels for external cladding or interior use. If this technology can service 20 per cent of market demand for pre-cast concrete, it could save a projected 225,000 tonnes of waste in formwork annually.

This is equivalent to the waste created by 112,500 Australians a year – the entire population of Ballarat.

High-end design

“With support from the Translating Research at Melbourne program and Wade Institute, the PAM research and technology has been geared toward commercialisation, with Curvecrete born as a start-up company,” Dr Loh says.

Highlighting its potential for high-end design, Curvecrete was last year shortlisted in the 2019 Melbourne Design Week ‘NGV Victorian Design Challenge’. Design professionals and students were invited to tackle the challenge of ‘waste’.

One of five professional firms shortlisted for the design challenge, the Curvecrete team, in collaboration with RMIT industrial designers Marcus Cher, Paul Meeuwsen and Travis Gemmill, centred their proposal around the concept for a chair manufactured using PAM’s innovative fabrication techniques.

The design demonstrated the functionality of PAM in its ability to produce refined decor alongside large scale industrial manufacturing.

It has recently been accepted into the Melbourne Accelerator Program, where it will benefit from an expanded support network and additional mentors for the Curvecrete team, allowing for a concerted focus on reducing waste in great design.

By Aengus Cassidy, University of Melbourne

First published on 20 October 2021.

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