Review on compaction and shearing-induced breakage of granular material
With ongoing expansion of the transport infrastructure to accommodate the need of growing population, the stress on natural construction resources, such as quarried aggregates, has been increasing. Hence, the use of alternative non-traditional waste material is becoming more popular. Coal wash, a by-product of coal mining, has been recently suggested as a substitute to traditional quarried materials. However, recent research showed that these waste aggregates have a weaker structure than conventional materials, which translates into significant potential for breakage upon compaction and loading. Therefore, it is important to quantify breakage and evaluate its influence on the final structure of the soil body and the associated geotechnical properties. This paper presents a critical literature review on compaction and shearing-induced breakage of granular material. The review addresses the available breakage indices developed in the literature to quantify breakage and their limitations. The factors affecting the degree of breakage and the influence of the latter on the different geotechnical properties of compacted granular materials is also discussed. The findings of this review could be extrapolated to waste materials and corresponding treatment methods could be developed to reduce their breakage potential, so they can be more confidently accepted as substitutes to traditional materials in transport infrastructure.