Influence of the Type of Binder on the Properties of Artificial Aggregates from Construction Waste

This research aims to produce artificial aggregates of the fine fraction of construction demolition waste (CDW). Before the investigations, the fine fraction of CDW (< 4 mm) is sorted in concrete and brick demolition waste and ground and sieved to comparable fineness. Two methods were chosen and compared for the production of artificial aggregates. For the first method, a sodium silicate solution was chosen as a binder to activate the starting material for producing alkali-activated aggregates (AAA) without a core structure. For the second method, different amounts of cement and water were mixed with the starting material to produce cement-activated aggregates (CAA) with a core-shell structure. In both methods, the aggregates were produced using a pelletizer. The performance of the aggregates was evaluated in terms of bulk crushing resistance, particle and loose bulk density, and water absorption. The results indicate that AAA and CAA reach properties in the range of lightweight aggregates. CAA achieves about 25% higher bulk crushing resistance than AAA. Cement content highly affects bulk crushing resistance and densities.