Application of particle packing to produce roller compacted concrete

Roller compacted concrete is used in mass concreting applications like dams and pavements due to certain advantages such as use of low cement content, made possible by blending with mineral admixtures like fly ash and adopting innovative placement methods. In this context, particle packing models help in selection of appropriate size and proportions of particulate materials to get suitable combination for optimum packing. In this article, control mixtures of M10 and M20 grade roller compacted concrete were designed based on US Army Corps of Engineers method. These mixtures were then redesigned by replacing cement with fly ash conventionally by conducting trials and also by using software based on a particle packing model. These modified mixtures were then compared with control mixtures for strength and durability parameters. It was found that concrete mixtures that were designed based on particle packing model using fly ash as cement replacement material, had better strength characteristics and superior durability performance than control mixtures and cement replacement mixtures at very low cement content. The proportion by which cement is to be effectively replaced by fly ash can be determined by particle packing approach, rather than conventional trial mixture procedures, which are time consuming.