Measuring concrete strength
The conventional method for monitoring concrete strength involves pressing cubes that cure outside the construction itself. These cubes have a different temperature than the construction concrete so their strength develops at a different rate, making this a poor strength indicator.
ConSensor does it differently. In the lab, ConSensor starts by making calibrations of strength in relation to maturity and conductivity. On site, the contractor uses these calibrations to accurately determine the concrete strength.
The main difference between ConSensor and other systems is that ConSensor uses 2 measurement methods:
- Weighted maturity (NEN 5970).
- Electrical conductivity, which diminishes proportionally with the hardening of the concrete.
Why does ConSensor offer two methods? First, as a failsafe, and second, to monitor the long-term integrity of concrete.
When you turn on the measuring device sometime after the pour, the system measures too little weighted maturity, giving you an estimate of the concrete’s strength that is too low.
In contrast, when using the conductivity method, turning on the device too late isn’t an issue—it gives you a correct strength value based on the actual conductivity at that moment.
Used together, the two measurement methods offer more certainty about the strength of the concrete and the setting process.
And in the long term, measuring the concrete’s conductivity serves as an indication of the concrete’s condition. An increase in conductivity after many years indicates an ingress of water and possibly ions, signaling the need to investigate the concrete’s integrity.
Let’s compare the methods for creating a calibration curve.