Wet packing of crushed rock fine aggregate

Abstract

It is well known that the performance of concrete is dependent on the packing density of the aggregate. All existing methods of measuring the packing density of aggregate are carried out under dry condition. However, these dry packing methods are sensitive to the amount of compaction applied and do not account for the effect of water in the concrete mix. In this research, a new method, which measures the packing density of aggregate under wet condition, has been developed. It is called the wet packing method and has the advantages that it is less sensitive to the amount of compaction applied and that it includes the effect of water. The wet packing method was compared to the dry packing method by applying both methods to measure the packing density of crushed rock fine aggregate. It was found that the packing density of crushed rock fine aggregate can be 24% higher under wet condition than under dry condition and that the addition of superplasticizer can have a marginal contributing effect. Furthermore, it was demonstrated that the beneficial effect of blending different size aggregates together is better revealed by the wet packing method than by the dry packing method. © 2008 RILEM.