Wet packing method for blended aggregate and concrete mix

Abstract

Although it is well known that the packing density of the particles in a concrete mix has great influence on the performance of concrete, the packing density is seldom directly measured and all codified methods for measuring packing density are carried out under dry condition. These dry packing methods do not account for the effects of water and any chemical admixture present and are not really suitable for water-solid mixtures containing cementitious materials and fine aggregate, which tend to form agglomerates under dry condition. To solve these problems, a new method, called the wet packing method, for measuring the packing density of cementitious materials, fine aggregate and mortar under wet condition has been developed. In this study, the wet packing method was extended to measure the packing density of blended fine and coarse aggregate as well as concrete mix. The results revealed that the packing density of blended aggregate and concrete mix is highly dependent on whether the aggregate and concrete mix are dry or wet. Hence, when measuring the packing density of blended aggregate and concrete mix, the wet packing method should always be used. © 2012 American Society of Civil Engineers