While housebuilders gaze into the future, researchers have been turning to the past for inspiration. Over the last few years, the DNA of concrete has been decoded and rewritten by scientists to make the material that built the Roman Empire fit for the future.
Hendrik Jonkers of Delft Technical University in the Netherlands first developed self-healing concrete, then Basilisk Concrete commercialised it. Since then, it has been pouring closer and closer to the mainstream. The magic solution uses a bacteria that produces limescale when it comes into contact with oxygen or water, filling the crack and essentially healing the wound.
However, the real excitement will begin when concrete can continually monitor, regulate, adapt and repair itself without any help. Smart materials promising to make this a reality include nanomaterials, multi-functional materials and biomimetic materials, which will essentially transform concrete into a living skin for the built environment.
At Rice University in Texas, researchers are working on programmable concrete, a modified version which is greener, more durable and flexible.
“We call it programmable cement,” Rouzbeh Shahsavari, an assistant professor of materials science and nanoengineering at Rice University, said. “It’s the first step in controlling the kinetics of cement to get desired shapes. It’s a hot area, and researchers are taking advantage of it. But when it comes to cement and concrete, it is extremely difficult to control their bottom-up assembly. Our work provides the first recipe for such advanced synthesis.”
Another ancient building material that is coming back in vogue is straw. Researchers at the University of Bath have proved straw to be a durable, affordable and environmentally-friendly building material. The scientific research has paved the way for homebuyers to get insurance and mortgages for straw homes, meaning these eco houses are likely to be the cream of the crop in future.
Straw walls provide two times more insulation than required by current UK building regulations, and can reduce fuel bills by up to 90%.
The walls are built using ModCell technology; prefabricated panels consisting of a wooden structural frame infilled with straw bales or hemp and rendered with either a breathable lime-based system or ventilated timber or brick cladding.
This technology combines the lowest carbon footprint and the best operational CO² performance of any system of construction currently available. In fact, as an agricultural co-product, straw buildings can be carbon negative as straw absorbs CO² when it grows.
Professor Pete Walker, Head of the Department of Architecture and Civil Engineering at Bath University, said, “As a construction material, straw is a low-cost and widely available food co-product that offers real potential for ultra-low carbon housing throughout the UK. Building with straw could be a critical point in our trajectory towards a low-carbon future.”
Glass is also being reengineered to be much tougher than it looks. HUF HAUS recently launched the HUF Connector, which allows glass to be woven into the structure of a building.
“The result of over five years of research, this unprecedented innovation is set to revolutionise the way glass is used; it is now possible to connect glass to timber, without the need for a buffer, so that the glass forms an integral component of a structure – and functions beyond the aesthetic,” said Peter Huf, Lead Architect for HUF HAUS in the UK.
“For the first time ever, we’re able to use to use glass in the same structural way as our traditional walls, affording an unprecedented design freedom,” he added. “Because of this technology, all internal and external walls can be made of glass.”
In a reversal of traditional roles, it could soon be common for windows and solar panels to be made from wood. Researchers at Stockholm’s KTH Royal Institute of Technology developed a new transparent wood material that’s suitable for mass production.
Lars Berglund, a professor at Wallenberg Wood Science Center at Stockholm’s KTH Royal Institute of Technology, said, “Transparent wood is a good material for solar cells, since it’s a low-cost, readily available and renewable resource. This becomes particularly important in covering large surfaces with solar cells.”
The optically transparent wood is a type of wood veneer in which the lignin, a component of the cell walls, is removed chemically. “When the lignin is removed, the wood becomes beautifully white. But because wood is not naturally transparent, we achieve that effect with some nanoscale tailoring,” said Berglund.
Among the work to be done next is enhancing the transparency of the material and scaling up the manufacturing process. “We also intend to work further with different types of wood,” Bergland.