‘SWEET CONCRETE’

The University of East London (UEL), in creative partnership with Grimshaw Architects, has developed a prototype floor slab made from sugarcane, as part of a groundbreaking project to find a new low cost, low carbon construction material.

The UEL’s Master of Architecture and Sustainability Research Institute, supported by Tate & Lyle sugars, has developed the innovative construction material with the trademark ‘Sugarcrete’.

The product, which has been developed over two years, uses sugarcane fibres which are left over after sugar sap extraction, which are known as bagasse, mixed with bespoke sand-mineral binders.

The result is a material which has the potential to be used and re-used in new or existing buildings, replacing both brick and concrete – and it is particularly effective for building in countries at risk of earthquakes.

Armor Gutierrez Rivas, Senior Lecturer in Architecture at UEL, explained sugarcane is the world’s largest crop by production volume, with almost two billion tonnes produced worldwide yearly.

This results in six hundred million tonnes of fibre bagasse as an arable by-product – waste which could be put to good use in the construction industry.

“Using a bio-waste-based product like SugarcreteTM, we could replace the traditional brick industry, offering potential saving of 1,08 billion tonnes of CO2, 3 per cent of the global CO2 production,” says Rivas.

“The built environment generates 40% of annual global CO2 emissions.

“Despite the global aim to hold global warning to 1.5 degrees Celsius, it is estimated that our global built floor areas will double by 2060.

“Therefore, we must develop alternatives to current construction methods.”

Testing of Sugarcrete by the UEL’s Sustanability Research institute has shown that compared to concrete production, Sugarcrete is cured within one week, while the process takes up to 28 days for concrete.

The product is also four to five times lighter than concrete and only uses 15% to 20% of its carbon footprint at substantially reduced costs.

As part of the research programme, UEL developed a prototype floor-slab made from sugarcane derived from SugarcreteTM and used advanced digital modelling and robotic fabrication to test the viability of the ultra-low carbon materials in construction.

Arcitectural firm Grimshaw’s previous research into interlocking geometries – using the form of the building components to create self-supporting assemblies – allowed SugarcreteTM to be deployed as a demountable, reusable, fire resistant composite floor slab, which can be applied, disassembled, or extended in new or existing structures.

“Sugarcrete when integrated as a floor slab adapts Abeille’s 1699 design for dry assembly flat vaults,” said Elena Shilova, architect at Grimshaw.

“The system is made of interlocking components which transfer loads across the slab between blocks, restrained using post-tensioned perimeter ties, reducing the steel content of the slab up to 90 per cent.

“Reducing steel, combined with the use of sugar cane fibres of different densities in a modular system, allows the slab assembly to avoid the potential risks of cracking which occur with traditional concrete in extreme situations, absorbing the effects of seismic shock – a characteristic vital in earthquake prone regions where sugar cane is cultivated.”

As part of the project, and working with Tate & Lyle Sugars, the team has started to identify sites in the sugar producing Global South, which have the opportunity to adopt Sugarcrete.

As well as providing an alternative, sustainable construction material globally, production of the material could provide particular advantages for sugar-producing communities, many of whom have to import materials that are poor performing for their environment, at high cost.

The intention is to work with local NGO’s to test a prototype.

Alan Chandler, Co-Director of UEL’s Sustainability Research Institute, said:

“By partnering locally, the production potential in each situation is evaluated, defining whether cement-use reduction can be made using locally created SugarcreteTM, or whether there is capacity to grow export markets for raw material or finished products to benefit GDP.

“This is particularly relevant for sugar producing communities where construction materials are frequently imported, environmentally poor performing, high cost and high carbon – for example a concrete block in Cuba, a major sugar producing country costs $3 – an average monthly salary is $148.”

Sugarcrete has been nominated for this year’s Earthshot Prize by former winners, Notpla, in the Build a Waste-Free World category.

In addition, researchers from UEL will publish their first set of SugarcreteTM  journal papers with its partners over the coming year, alongside carrying out further research on structural, durability and acoustic properties of the constituent materials.