Environmental Friendly Lightweight Artificial Aggregates through Industrial Waste Stabilization

The production of lightweight artificial aggregates proposed in this study derives from industrial waste recovery activities, such as fly ash (FA) and ground granulated blast furnace slag. The aim is to reduce the compromise of the environment and human health, through the recycling of special waste. The use of inert aggregates from recovery from industrial waste encourages the reduction of soil consumption, the waste of natural aggregates, consequently limiting the consumption of waste materials from quarries, as well as facilitating the recovery of waste that would inevitably end up in landfilled or abandoned in the environment. Specifically, in the present work, the lightweight artificial aggregates were produced by cold bonding granulation technique. All the mixtures, made by 80% of FA with various composition of cement and granulated blast furnace slag, were characterized by density values ranging from 1.63 to 1.66 g cm-3 suggesting their suitable classification as lightweight aggregates (LWAs). Water absorption capacity (WAC) and open porosity values decreased with the increase of the percentage in cement. The impact test results indicate that all the aggregates have proved to be suitable as filling for road pavements. The best crushing strength values (1.86 MPa) were observed for the mixture contain the highest amount of cement. Aggregate leaching tests indicated a significant release of chlorides and sulphates while the release of heavy metals was lower than the limits set by the standard UNI 10802.