Role of rubber crumbs in compacted coal wash for transport infrastructure

The expansion of transportation infrastructure systems is a vital aspect of the fast-paced development that the current civilization is witnessing to accommodate the needs of growing communities. This expansion will require larger quantities of raw materials for the construction of transportation corridors, which are likely to be supplied from natural quarries. On the other hand, environmental agencies are urging industries to adopt more sustainable practices by introducing restrictions on the quantity and quality of quarried aggregates, and therefore many industries are considering the reuse of waste materials in engineering projects. In this study, a mixture of coal wash (CW), a by-product of the well-established coal mining industry, and rubber crumbs (RC), produced by shredding waste rubber tyres, is proposed as a potential alternative to traditional aggregates that can be used in transportation infrastructure sublayers such as the capping layer is railways. While CW may exhibit a behaviour that is somewhat comparable to granular materials, the strength and deformation of compressible and elastic rubber are considerably different, thus affecting the compaction characteristics of the mixture. Accordingly, the effect of rubber content on the compaction efficiency under the same energy level and under increasing energy levels was evaluated. An optimum compaction energy range was proposed based on an acceptable void ratio and a minimum level of particle degradation...