Sustainable use of reclaimed ballast rejects for construction of rail corridor access road: An Australian experience

Ballast cleaning practice results in depositing large quantities of fouled ballast in the rail corridors on and around existing access roads, drains and embankments. Therefore, such stockpiles of waste ballast may result in safety issues for the staff driving on rail access roads and moreover, may damage the drainage paths around the railway embankments leading to reduce the service life of the railway formation. Once ballast is cleaned, remaining materials with a particle size of smaller than 30 mm (i.e., called fine ballast) are discarded and therefore, the accumulation of such waste is challenging. In this study, the potential re-use application of fine ballast to construct access roads is investigated. This helps to remove the waste stockpiles and therefore, reduce the access road construction costs. A series of Modified Proctor compaction tests and CBR tests carried out on the fine ballast samples collected from stockpiles along Central Queensland coal network (CQCN) in Rockhampton area. The results indicated that the sample with a particle size of smaller than 26.5 mm performs satisfactorily in soaked CBR tests. An access road was constructed at the Waitara rail yard on the Goonyella line using the fine ballast (<26.5 mm) and the post-construction static plate load tests showed less deflection of the compacted base compared to that of the roads constructed with standard materials (<19.0 mm). Therefore, the waste fine ballast provided the confidence that it can perform well as an access road material.