Author:

Abstract:

Since over 90% of C&DW consists of stony fraction (concrete, bricks and mixed aggregates), it can be reused as recycled aggregates in various applications after crushing. C&DW can serve as filling material in roads construction (low grade application) or as aggregates to make new construction materials (high grade application). Concrete Aggregates (CA) have the potential to be reused in high grade applications. However the current practices in recycling of C&DW do not separate CA from the bricks and the mixed fractions. This results in a low quality product which can be only used in low grade applications. This is called downcycling, so called because of the value gap between recycled concrete and its intrinsic value. The presented study aims to identify the key environmental gains and drawbacks when CA are recycled in high grade applications. Two different scenarios are analysed: downcycling- representing the current situation, in which CA are recycled in low grade applications (roads construction) and upcycling- where CA go through an advanced cleaning process that makes them suitable to be used in high grade applications (new concrete). Environmental performances of both scenarios have been evaluated using a Life Cycle Assessment (LCA) approach. The LCA study concluded that the upcycling scenario has slightly lower environmental impacts compared with the downcycling scenario. In addition to the slight environmental gain, the upcycling allows also to close the recycling loop for CA.