Innovative system tracks strength development of concrete during hardening real-time

Anyone working with concrete must be able to determine at any time whether that concrete is strong enough to continue construction and remove scaffolding or formwork. Proper methodology is crucial in this regard. With ConSensor, you can monitor real-time concrete strength development during hardening. This system differs from other measurement systems because it combines two measurement methods: the weighted maturity method and electrical conductivity.

Text | Johan Debaere  Image | ConSensor

The ConSensor is easy to attach, even in hard-to-reach places.

The strength development of concrete can be determined in several ways. For example, one can use test cubes in the same concrete as the structure or apply the method of weighted maturity, where the temperature is measured to determine the values. Since the concrete in the cubes and the structure does not cure at the same time, the results are inaccurate. The temperature measurement method also has its limitations. "Therefore, in 2010 we developed a new system together with TU Delft, which provides a much more accurate monitoring of strength development," states Wim Stenfert Kroese, CEO of ConSensor. "In this solution, sensors measure the temperature of the weighted maturity method and the electrical conductivity, which decreases proportionally with the hardening of the concrete. A robust DataBox reads the measurement data and sends it to a web platform, where concrete mixtures, calibration lines, projects and measurements are created and managed. All data can be monitored in real time on a smartphone, tablet or computer, and the system can even send important information via SMS."

The ConSensor DataBox can simultaneously monitor 2 different concrete mixtures.

ConSensor technology therefore works more simply, accurately and quickly than other methods. After all, based on reliable data, one can always make the right decisions and reduce construction time and costs. Furthermore, by measuring, one can adjust the concrete mix to the current temperature and reduce cement consumption. The concrete sensor is also used to monitor concrete mix without cement, such as geopolymer concrete, which will be increasingly used in the future. The equipment is also being further optimized in close cooperation with concrete experts to meet market needs and requirements. The system is so user-friendly that no further support is needed on the construction site.

In practice

ConSensor rents or sells the equipment to concrete plants and contractors for a wide variety of applications. In the construction of the Terraced Tower in Rotterdam, the sensor was used to monitor the hardening of the concrete of the storey floors. Once the set strength was reached, the system sent an SMS to the contractor, who could thus re-stamp the floor and deploy the formwork on the next floor without losing time. During the pouring of the concrete foundation for the new Van der Valk hotel in Venlo, temperatures and hardening were monitored in real time, allowing the concrete to be supplied and distributed across the construction site in one smooth motion.

On ConSensor's web platform, the measurement data are conveniently displayed.

"Also during the construction of a storm surge barrier in Nieuwpoort, the concrete sensor prevents loss of time during the construction process. ConSensor is being used here to monitor the strength development of the concrete at various crucial locations in a deep construction pit. The foreman receives an SMS with information, allowing him to remove the formwork at the right time," concludes Kroese concluded. "For the measurements of the concretestrength in the Leopold II tunnel in Brussels, extra-long sensors of 25 m were made. New emergency exits are being made there and the stairwell in front of it is 24 meters deep. In the construction pit is poured with underwater concrete to allow groundwater to stand during pouring and curing. As soon as the measurement data indicated a correct curingven, the pit is drained and the stairwell is finished." In any project, ConSensor's data provides greater certainty about concrete strength and tie time, creating increased efficiency on the construction site.