Sensors in Concrete: New Technology to Improve Efficiency and Avoid Material Waste
Control of concrete strength and maturity in large-scale projects has traditionally been recorded and measured manually. Nowadays, there are new technologies that allow builders to melt sensors directly into the concrete, which –connected to a transmitter– show continuous data on the material’s temperatures, sending this data wirelessly to the cloud platform. The software then automatically calculates maturity and strength based on historical data, so the concrete mix and strength development process can be followed from any device and in real-time.
These sensors, based on 0G technology from Sigfox –one of the main IoT (Internet of Things) operators worldwide– have facilitated the construction of one of the most innovative architectural projects in Europe, the Cactus Towers (Kaktustårnene) in Copenhagen, helping calculate the exact moment to remove the formwork that shapes its characteristic façade.
We spoke with Rebecca Crowe, Managing Director of Sigfox Spain, to learn more about this new technology.
José Tomás Franco (JTF): Before talking about the system, could you tell us more details about the Cactus Towers project (Kaktustårnene) and its technical and material complexity?
Rebeca Crowe (RC): The Cactus Towers, expected to be ready in spring 2022, have been designed as residential buildings, intended as a youth home in central Copenhagen. They have a technical complexity that few buildings have, due to the peculiar pointed shape of their façades, which gives rise to the name. They have a hexagonal core with covers that appear to twist into level balconies. One of them is 60 meters high and the other a little more, about 80 meters, and both house 495 apartments with modern aesthetics.
In terms of materials, special attention is paid to the concrete formwork to achieve a solid foundation, which is an additional challenge, since large structures with a number of floors normally require cooling to guarantee product quality. In this sense, the monitoring of the condition of the concrete plays a fundamental role, as it is essential to give the towers their twisted and very particular shape.
JTF: How did the process of real-time measurement of the condition of the concrete through sensors work?
RC: For this specific case, the builders used a solution from one of our partners, Maturix, which consists of a comprehensive tool that has allowed them to control the strength of the concrete in a much more efficient way which is very different from the manual records that were being used previously and that involved extra work.
With thermocouples fused into the structure, the concrete temperature can be accessed in near real-time. As they are connected to a transmitter, these thermocouples dump the information wirelessly to the cloud. Maturix has software that is responsible for calculating maturity and resistance based on historical data, which is an advantage when making adjustments in project management. In addition, with a building of this caliber – so extensive and with a large number of subcontractors – it is a plus in terms of organization and time measurement.
JTF: What is 0G technology and how does it work?
RC: The second part that has made the project possible, together with Maturix’s sensors and technology, is our 0G network. It is a simple, low-consumption, long-range alternative for IoT connectivity, widely used in the world of industry, logistics, or asset monitoring. As it is based on radio technology, it overcomes some of the traditional limitations of other alternatives based on cellular networks or SIM cards, such as scalability or being able to provide service in interiors, rural areas, or, in this case, monitor the temperature of concrete in real-time.
The 0G network is the first connectivity option exclusively designed for the IoT. Since most industrial IoT requirements only need a small data package, we decided to focus on a low-power network, to achieve a much greater reach in these applications.
JTF: To what extent does this technology make it possible to create more sustainable solutions with concrete?
RC: This technology is designed to streamline decision-making and improve efficiency in the use of materials. Having updated information in real-time, it is much easier to avoid material waste while improving the final quality of the project.
JTF: How do you see the future of concrete in the world of construction and its relationship with the IoT?
RC: Concrete is one of the most used materials in the construction sector and any novelty that represents an advantage from the first to the last phase is sure to be welcomed in a sector as essential as construction.
This sector, on the other hand, is increasingly committed to efficiency, like so many others. Sustainability has ceased to be a commercial slogan and has become a pillar of business and the large-scale digitization of construction in many of its areas. It is already more common than just a few years ago, and this is just one of many examples.
Thanks to the IoT, data on the resistance of this material can be obtained, which is a key factor when it comes to saving resources but also to ensure that buildings are in good condition.
I believe that more and more sectors are feeling encouraged to use this type of technology due to the potential they have and, in the case of construction, the IoT can be applied at different stages of the work process, helping in the design and subsequent maintenance of buildings. The use of connected sensors, as in the case of the Cactus Tower, provides architects with up-to-date information on the development of the project, something that is useful for any building, but especially in bridges and tunnels that tend to suffer regular damage.
Undoubtedly, construction is undergoing a revolution with the arrival of the IoT and I believe that it is a path that should be used to transform the businesses of the sector, to continue innovating, and above all to improve the efficiency of the processes.
Check more details of the Cactus Towers designed by BIG here.