Electrical Properties of Freshly Mixed Concrete

Abstract

The current procedures for the design of concrete mixes are based on specifying target workability and strength. Graphs are then used to determine the masses of constituent materials. Small changes in initial water content will result in the concrete mix not achieving its target, as water is necessary for the workability and hydration of cement, to produce cement paste that acts as the binder. Therefore, it is important to understand the distribution of water in fresh concrete to achieve the required workability, strength, and durability. This paper considers the use of electrical measurements to study the movement and special distribution of water within freshly mixed concrete. The technique is used to determine moisture content and rates of water absorption and adsorption of individual components forming the concrete. A theoretical model is developed, and simplified, using electrical formulas. The results from this investigation show that the cement paste is the primary governing factor in determining the electrical resistance of a fresh concrete. However it also shows that all constituents have some influence.