Electrical Conductivity of Concrete and Mortar Prepared with Calcareous Aggregates for Construction in the Gulf of Mexico

The electrical conductivity of mortar and concrete samples was measured. Series of samples were prepared with crushed limestone (approximately 95–98% calcium carbonate), water-to-cement ratios of 0.53, 0.59, 0.70 and 0.76 and cured at 7 and 28 days. The conductivity, for both mortar and concrete, in chloride solution of concentration 1M, 2M, 3M and 4M, increases as the chloride concentration in the solution increases. The conductivity of mortar specimens take values between 0.60 and 2.18 mS/cm, while the concrete samples have values in the range from 2.10 to 5.44 mS/cm. For concrete samples, the conductivity decreases with curing time, which indicates that the conduction is, in such a case, due mainly to capillar porosity. The conductivity values of mortar increase, when the curing time increases. It is suggested that such behavior is due to the hydration process of the paste in the mortar and the water transport in the pore gel structure resulting thereafter.