Monitoring the Electrical Resistance of Concrete During One Slow Freeze Thaw Cycle, A Method for Assessing The Water-Cement Ratio

Many attempts have been done to increase the service life of the concrete structures. In this regard, the concrete properties should be evaluated by non destructive testing methods (NDT) periodically to estimate how the structures may behave in the future. It is so important to select a proper and simple method to examine the concrete properties during the service life. In the present paper, try has been done to evaluate the water cement ratio of the hardened concrete via non destructive measurement of the electrical resistance the concrete during one freeze thaw cycle. Five mix proportions were prepared. The electrical resistance of the cured specimens within one slow freeze thaw cycle was monitored within 24 hours at 1 minute interval. The results declared that as the temperature dropped to zero or minus 15 °C, the electrical resistance variation of concrete is highly affected by water- cement ratio. The characteristics of the curve such as slope, upper and lower limits of electrical resistance curve are dependent on the water-cement ratio of the mixture. The results of the present work can relieve engineers´ anxiety about the proper water-cement ratio which was used in the concrete mixture.