Factors Affecting the Relationship Between Total Porosity and Electrical Resistivity for Concrete Repair Materials

Abstract

The paper examines the properties of five different types of repair and substratematerials, including conventional mortar, fly ash mortar, silica fume mortar, conventionalconcrete substrate, and high-performance concrete substrate materials. Assessment wascarried out on the basis of some physical properties (total porosity, and electrical resistivity).These properties were measured at early age and later after 14 weeks of exposure conditionsto 6 % (by weight) of sodium chloride solution to simulate typical marine environment.The results show that the electrical resistivity and total porosity measurements appearto be related and the measurements obtained are affected by the pore structure of thematerials. It is also expresses that if a material has grater proportion of coarse aggregates (e.g.the substrate concrete in this study) it will appear to have a lower porosity although theporosity of mortar surrounding the aggregates could be higher. This makes comparisonsbetween materials containing different aggregates proportions and size difficult.