Merlin is used to measure the bulk electrical resistivity, or its inverse, the bulk electrical conductivity, of saturated specimens or cores according to ASTM C1876 “Standard Test Method for Bulk Electrical Resistivity or Bulk Conductivity of Concrete”.
The resistivity (or its inverse conductivity) of a saturated concrete specimen provides rapid information on the resistance of the concrete to penetration of chloride ions by diffusion. The term bulk is used to indicate that the measurement is made through the specimen as opposed to a surface-based measurement.
Merlin uses the four-point measurement method for accurately measuring the specimen resistance to an electrical alternating current (325 Hz) current, minimizing the effects of the conductive sponges and the pressure applied to the electrodes. A voltmeter measures the voltage drop across the specimen, and an ammeter measures the current through the specimen. From the measured current I and voltage V, the bulk resistivity or its inverse conductivity, are calculated and displayed.
Two versions are available depending on the size of specimens that want to be tested. The operation is very simple and a measurement is obtained within two seconds.
Concrete resistivity meter