It is common knowledge what concrete is made of: cement, water, and aggregate. The popularity of this building material – that can be formed and is extremely robust once hardened – is also undisputed. The problem here is the climate-intensive manufacture of the binding agent: cement. For future-proof construction, MOBBOT exploits the aerodynamics of sprayed concrete combined with an automated robot. This not only enables locally sourced and recycled primary materials to be used but also lower quantities thereof.
Many aspects of the construction industry have not undergone any further development in years. Recording data in real time using robotics is a new way of optimising these processes. ‘You can only improve what you can measure,’ explains Aurélie Favier, head of Sustainability at MOBBOT. This innovation from the small company from Fribourg is having a significant impact on the industry. ‘By logging real-time data and directly translating this into work in progress, the agility of production can be optimised, and the amount of concrete used is drastically reduced,’ states Favier. This brings about improvements in economy, ecology and social responsibility.
The name MOBBOT refers to the key to the entire system: the mobile robot. The system can be moveable and can be set up in just a few hours on jobsite. One major advantage over conventional 3D printing is that elements such as cable chambers, shafts or supporting walls can be tailormade with thicknesses of eight to thirty centimetres, for example, with reinforcement bars and lifting anchors that would otherwise have to be cemented in later integrated right from the start. This makes logistics safer and an order that would otherwise take several days can be processed within 24 hours. Together with Cablex, a subsidiary of Swisscom, multiple successful projects have already been implemented for the construction of concrete chambers for signal and telecommunication cables or low-, medium- and high-voltage lines. The city of Zurich’s civil engineering office is another well-known customer.
At the end of 2021, the start-up entered a new field: tunnel construction, leaving the research environment for a real construction site and moving from infrastructure components to even more data management. ‘Our knowledge of the IoT and the demand for this is constantly on the increase. We’ve thus focussed on the collection of data and making this accessible on the dashboard. This means that you can at once see where there’s need for improvement,’ says engineer Aurélie Favier, one of MOBBOT’s eleven employees. The continuously captured data is sent in real time to the personalised online dashboard that can be accessed from every device and that constantly monitors work, enabling any necessary adjustments to be made. A sizeable number of projects are currently underway, with both the challenges and the potential enormous. ‘We’re right in the middle of things at the moment,’ adds Favier with a smile.
The use of more climate-friendly primary materials for concrete, such as ‘low carbon cement’ or earth, is one way of making construction more sustainable. Another much more effective solution is to use less material. A lot of waste in generated when using concrete spraying technology that must be disposed of and thus transported away from the site. This is an expensive and carbon-intensive undertaking. Aurélie Favier explains her system as follows: ‘We’re working on reducing this waste. If you measure the required thickness and distances precisely by recording data, you can save a lot of material and thus cut your carbon emissions.’ And the statistics back this up: about CHF 500,000 and 1,000,000 kilograms of CO2 can be saved per kilometre of tunnel.
Another new feature is the use of recycled material from zero to four millimetres and aggregates measuring four to eight millimetres. This fine material that to date could not be fully valorised. As part of the Kickstart programme and together with Holcim Switzerland, pumpable concrete recipes have been developed that show a high mechanical performance after just 24 hours. Up to 45% of recycled aggregates under eight millimetres is used, enabling the wall thickness to be reduced and carbon emissions to be cut by a third per cubic metre. ‘Our aim is to think in terms of the circular economy and save time and resources throughout the entire process,’ Favier elaborates.
Agnès Petit Markowski, a cosmo chemist with a degree in mining and mineralogy, founded start-up MOBBOT in 2018. After many years of experience in the construction industry, she knows what needs to be done to bring about change. ‘We aim to encourage a highly productive organisation made up of different employees who contribute various views and come from a range of cultures. This diversity pays off,’ states Aurélie Favier. The motivation to revolutionise the construction industry and the aim of finding a solution for the huge amount of concrete waste generated is promoting sustainable construction. MOBBOT shows which direction the industry could take to protect our climate. And this is very promising.
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