Could a soil-based construction material solve the world’s housing crisis?

Adding chemicals to soil could create an environmentally-friendly construction material to build homes in developing countries, scientists say.

Researchers at the University of Bath are exploring the potential of geopolymer-stabilised soil, which is created when alkaline chemicals are added to soil. They believe it could be transformative in developing countries where houses are desperately needed.

The UN estimates the world’s population will grow by an additional two billion people by 2050, with most growth from developing countries in Africa and Asia. They say hundreds of millions of additional homes will be needed in these regions over the coming decades.

Geopolymers are strong materials, similar to cement, however, they don’t need to be heated to the same high temperatures to react. They can be fired at 80°C whereas cement and fired bricks usually require over 1000°C, making geopolymers potentially more energy-efficient to produce.

The university says the task of housing a growing population in poor urban areas of the least economically developed countries poses a significant challenge and requires the identification of construction materials which are affordable, sustainable and environmentally-friendly, as well as meeting the social and cultural needs of urban dwellers.

Alastair Marsh, postgraduate researcher in civil engineering at the University of Bath, is chemically and physically testing a range of soils to understand what happens when soil undergoes a geopolymerisation reaction and he will ultimately determine if these new materials could be used to build quality, affordable and sustainable housing.

He said: ‘The construction materials we have used so far in the 20th and 21st centuries have been very good, but they’ve come at a high energy and carbon cost.

‘We’re trying to find more environmentally friendly alternatives. We’re using a process called geopolymerisation to make sustainable bricks out of soil. In this reaction, we produce a natural kind of cement that glues the soil together, making it stronger and more durable.

‘The advantage of this reaction is that it has a far lower energy cost. I’m hoping that through this, we can make new construction materials that are practical, affordable and environmentally sustainable.’

Professor Andrew Heath, of the University of Bath’s department of architecture and civil engineering, added: ‘This research is key to the development of sustainable housing around the world. It has already led to a joint India and UK government funded UKIERI project looking at developing sustainable housing in India, in collaboration with the Indian Institute of Science in Bangalore.’

Thomas Barrett
Senior journalist - NewStart Follow him on Twitter


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