Electrical Resistivity Measurements on Hardened Concrete Exposed to Various Curing Conditions

Abstract

Evaluating concrete quality and performance, especially determining the resistance of concrete to fluid and ion ingress, is fundamental to estimating concrete’s durability and predicting the service life of concrete structures. Both bulk and surface electrical resistivity tests have gained increasing interest as rapid and repeatable indicators of concrete’s resistance to fluid ingress. In this study, concrete electrical resistivity was measured at the ages of 56 and 91 days on specimens from five concrete mixtures exposed to different curing environments and storage solutions. Both bulk and surface resistivity of concrete in each curing condition are compared, and the effect of curing methods on electrical resistivity is discussed. The results show that conditioning in a highly-conductive storage solution, such as a simulated pore solution, led to a lower concrete resistivity measurement than when stored in saturated limewater. The effect of mixture compositions on measured resistivity revealed that for the same cementitious materials, the electrical resistivity increased as the w/cm ratio decreased, and a linear correlation between the w/cm ratio and concrete electrical resistivity was obtained.