Particle packing theories and their application in concrete mixture proportioning: A review

The mixture proportioning for various types of concrete requires thorough understanding of the material characteristics of its ingredients and its behaviour in the fresh and hardened states. The performance of concrete is greatly affected by the type and degree of packing of its constituents. Thus, a knowledge of the concept of particle packing and its influence on concrete performance is required to enable a mixture designer to select from a wide range of cement replacement materials. The task of selecting the right combination of materials that will enhance the performance of the concrete becomes tedious when adopting trials involving adhoc replacement of materials, and unexpected behaviour is often encountered in the resultant concrete. A more suitable method is to design the concrete mixtures based on optimal packing of the granular particles, and improved flow properties of the cement paste using a superplasticiser. This article reviews the research studies of various particle packing investigations carried out across the world, with a particular emphasis to concrete. One of the particle packing model, namely Andreassen model, has been validated for concrete application. The use of a software based on one of Andreassen model to design various concrete mixtures has also been described.