Evaluation of the effects of hydrothermal curing on the mechanical behavior or mortars characterized by MSWI bottom ash fine aggregates

Nowadays, the production of MSWI bottom ash (BA) is necessary for the optimization of the disposal of household waste. However, a main concern is linked to the leaching of contaminants, such as heavy metals and salts, in the surrounding environment. By washing, BA is cleaned from most of the salts, while the release of heavy metals is not easily achieved. After such treatment, BA is mostly used as aggregates. The use of BA in the presence of cement can reduce the leaching of heavy metals, since the reduction of porosity leads to a superior immobilization capacity. Moreover, due to its influence on the matrix densification, autoclaving can be useful for systems in which secondary building materials are involved. However, hydrothermal curing is not widely studied for bottom ash application as aggregates in mortars. This paper will address the influence on the strength behavior of autoclaved mortars with 25% BA, as sand replacement.