24 Years of experience with the electrical conductivity to determine material properties of concrete

A. van Beek, W. Stenfert Kroese

ConSensor BV, Rotterdam, the Netherlands

24 Years ago, the concept of using the electrical conductivity to characterize the strength development of young concrete was the starting point for a research program that resulted in the ConSensor. This sensor system is now used all over the world to monitor the strength development of young concrete. Scientists of several universities are now interested in other possibilities to use the electrical conductivity as a parameter to monitor concrete because it is not only related to the strength development it also gives information about other characteristics like the setting time and the durability of concrete.

In this paper the latest experience and research results will be presented, including the relationship between electrical conductivity and
• strength;
• setting time;
• durability of concrete;
• conductivity and temperature.

The first three topics find their origin in the microstructure of cement and how this microstructure changes in time. These relationships can therefore be described with microstructural models. The fourth topic, the temperature coefficient is based on the theory of the activity of ions in the pore water.

Key words: Material model, electrical conductivity, strength development, material characterisation, microstructure