Behaviour of cement-treated MSWI bottom ash

Abstract

MSWI bottom ash is the residue of combustion. The use of bottom ash in road construction is wide spread. French legislation forbids the disposal of reusable waste in special landfill from 2002. Moreover, arringt du 9 mai 1994 provides environmental criteria (leaching threshold, etc), and evaluates this material according to utilisation in road construction. In such applications, bottom ash is often treated with binder to improve its mechanical features. Nevertheless, bottom ash is subject to chemical problems. These problems induce an expansion, which brings about cracking and finally road destruction. Therefore, it is necessary to estimate the swelling potential of MSWI bottom ash prior utilisation. This is one of the aim of the European contract Mashroad(contract BRST CT97-5150). This study involved four years of work on cement treated MSWI bottom ash. It examined different tests that show the importance of oxidation of aluminium in the swelling reaction and the efficiency of different treatments. Different binders were used in order to have different proportions of clinker. The kinetic aspects of aluminium-binder reaction were also studied. Finally, we present a special cell to measure the swelling pressure of these materials. (A) For the covering abstract see ITRD E121685.