Utilization of crushed concrete aggregate in light rail construction

As the popularity of light rail is growing, it has become apparent that there is a need to examine the possibili-ties of using recycled crushed concrete aggregate (CCA) in light rail construction as well. CCA has been used in Finland for road and street construction since the early nineties. Experiences have been good. In the follow-up studies of trial sections, higher values for bearing capacity were measured for the structures with CCA than for the reference structures constructed with crushed rock. The nature of the stresses in the sub-ballast layers of a light rail structure can be compared to the stresses in a road structure. Thus, it can be assumed that CCA is a suitable material to be used in the unbound layers under the ballast bed in a ballasted light rail track or under the concrete slab of a slab track -type light rail track. Experiences and research findings from Fin-land and other countries were collected as a literature review and light rail structure was studied on the basis of the experiences in road structure. In addition, stresses in a light rail track bed caused by train loads were estimated using a multi-layer linear elastic calculation approach. Using CCA in the ballast bed would require additional research, as the train loads in a ballasted track might cause different, more abrasive wear on the ballast material compared to the stresses in a road structure or the lower layers in a track structure.