The effect of compaction on the leaching and pollutant emission time of recycled aggregates from construction and demolition waste

Urban solid waste from demolition and construction engineering sites has been demonstrated to be mechanically suitable for reuse in civil infrastructures. However, the application of recycled materials as a replacement for natural aggregates demands an assessment of the pollution potential of the material in its second life cycle. ly, plant managers of construction wastes assess the materials according to concise leaching tests that do not consider the compaction stage of the materials when they are applied in civil infrastructures. For that reason, the aim of the present study is to evaluate the effect of compaction on the leaching behaviour of concrete and mixed recycled aggregates. olation test for materials under compaction conditions was designed. The release levels measured in the water percolated through the compacted aggregates were compared with a conventional percolation leaching test. Besides, the compliance test allowed identifying the most conflictive elements according to the measured concentrations in the leachate: chromium and sulphate. The results revealed that under compaction, the highest levels of release were obtained for the concrete material. It was due to its high susceptibility to compaction which increased the content of fine particles affecting to the leaching behaviour. The study also includes the formulation of an equation to determine the emission release time of pollutants. Calculations were developed for two common applications as granular material: embankments and structural road layers.