Aggregates for quality concrete from debris using optimised crushing

Worldwide, natural disasters and conflicts result in damaged or collapsed buildings requesting clearing of debris and reconstruction. The on‐site recycling of concrete waste into new structural concrete reduces the utilization of raw materials, decreases transport and production energy cost, and saves the use of limited landfill space. Currently, recycling involves the use of recycled concrete aggregates (RCA) as road base material or in non‐structural concrete with low strength requirements. Hence, the application in structural concrete is limited.  In order to improve the applicability of RCA in structural concrete, an optimised crushing and sieving method is advised. To this aim, a modular rapid deployable clearing kit has been designed, clearing (concrete) debris, and processing this into quality aggregates for new concrete to be used in local reconstruction. Since the quality of the initial concrete is unknown, errors can be made when it was produced
(e.g. not enough cement, too much water, etc.). These defects are not detectable by the naked eye; however, they cause a weakening of the structure. In term, clearing the hardened cement paste from the aggregates via optimised crushing minimises the influence of the initial concrete quality on the quality of the recycled concrete aggregates. Together with the fact that cement paste absorbs a significant volume of water, optimised crushing makes application of recycled concrete into new concrete far less troublesome.