In a recent research published by the University of Toronto, the relationship between the concrete maturity and it's electrical resistivity was studied. In this thesis entitled "The Role of Concrete Maturity in Resistivity-Based Performance Specification" by Gita Charmchi under the supervision of Dr. Doug Hooton, various electrical resistivity measurement devices were also utilized and compared with each other. These include Giatec RCON, Germann Instrument Merlin, and Proceq Resipod. It was shown that RCON provides relatively accurate results (±5%) on a model electrical circuit having resistance and capacitance properties.
This research aims to develop a standard method for estimating concrete bulk resistivity via the maturity method. Eight different concrete mixtures were cured in different environments and monitored for resistivity development with relation to specimen maturity. Additionally, various factors and their effects on bulk resistivity readings are discussed, such as: degree of sample saturation and the saturating fluid. Furthermore, three commercially available resistivity meters are compared: the RCON by Giatec Inc., the Merlin by Germann Instruments and the Resipod by Proceq.
Due to the sensitivity of bulk resistivity development to curing temperature, a log-linear equation relating bulk resistivity and maturity of a particular concrete mixture could not be developed. Calibration between the three commercially available resistivity meters continues to pose a challenge for the standardization of resistivity-based performance specifications due to the difference in results produced by each meter, an average of +/- 9.0%.
The original thesis can be downloaded from here
|Concrete Maturity is a reliable and standardized method for real-time strength estimation of concrete in a job site. Learn more about the concrete maturity concept, measurement and application here.