Upcycling of demolition material from concrete and brick for the production of cold-bound, alkali-activated lightweight aggregates

This paper deals with the production of artificial aggregates based on the recycled fine fraction (≤ 4 mm) from construction demolition waste. Concrete powder, brick powder and their combination were used to produce aggregates through pelletisation using sodium silicate solution as an activator. For all aggregates, efficiency, bulk crushing resistance, particle density, water absorption and loose bulk density were evaluated. The bulk crushing resistance was evaluated for samples cured with different methods. A higher proportion of concrete powder increased the strength and density. The aggregates were successfully formed with bulk crushing resistance and particle densities in the range of lightweight aggregates.