Use of municipal solid waste incinerator bottom ash as aggregate in concrete

Abstract

As a result of their chemical and mineralogical characteristics, bottom ashes from municipal solid waste incinerators can, in principle, be used as aggregates in the production of normal strength concrete. However, because the ashes contain concrete-damaging components, such as chlorides, sulphates and organic compounds, or excessive quantities of fines, aluminium and waste glass, recycling becomes problematic. In particular, inclusions of aluminium in the ash particles and a glass content of about 15% cause considerable cracks and spalling in concrete specimens within a very short time. The harmful substances can be reduced or removed by additional treatments, such as upstream sieving and washing, waste glass separation, and lye treatment with sodium hydroxide solution. Tests on concretes with 2–32 mm bottom ash as coarse aggregates indicate that the quality of the ash is actually improved by the additional processing. Thus concretes with a compressive strength of C20/25 can easily be produced. Similar to concretes made with recycled aggregates, these concretes exhibit 15% lower compressive strength and E-modulus but twice the porosity of control specimens containing exclusively natural sand and gravel. However, only those concretes that were made with ash with a low aluminium content as a result of lye treatment remained free of damage.

Effect of chemical treatment of MSWI bottom ash for its use in concrete

“…Due to the relatively minor environmental impact expected when MSWI bottom ash is used with construction materials, a number of research studies have been conducted on the use of bottom ash in road construction (Bruder-Hubscher et al, 2001;Forteza et al, 2004;Izquierdo et al, 2001;Lucido and Wilson, 2002) and in concrete (Bertolini et al, 2004;Jurič et al, 2006;Keppert et al, 2012;Müller and Rübner, 2006;Rubner et al, 2008). Efforts have focused on the use of bottom ash as a replacement for aggregate or cement.…”

“…Unlike successful applications of other recycled materials in concrete such as recycled aggregate concrete (Gökçe and Ş imşek, 2013;Saravanakumar and Dhinakaran, 2014), coal fly ash (Gao et al, 2013;Wang, 2013) and others (Ahmadi et al, 2014;Ferreira et al, 2014;Kwan et al, 2013), not many successful uses of ash addition have been reported. This is mainly due to the side effect caused by the chemical reaction of aluminium in a high alkaline environment (Aubert et al, 2004;Bertolini et al, 2004;Müller and Rübner, 2006;Rubner et al, 2008). The presence of metallic aluminium in bottom ash causes an evolution of hydrogen gas and the gas is entrapped within concrete by the following chemical reaction (Aubert et al, 2004;Müller and Rübner, 2006;Sorlini et al, 2011) 2Al þ 4OH À þ 2H 2 O !…”

Construcción de esculturas de hormigón con elementos procedentes del reciclado

“…Incluso se han incorporado como aditivos al hormigón residuos provenientes de la industria del automóvil (6), elementos de circuitos electró-nicos (7,8), y otros tipos de residuos, incluso de origen orgánico (9,10). En definitiva la búsqueda de un "hormigón verde" como lo definen Damtoft (11) y C. Meyer (12) capaz de actuar como catalizador para poner de nuevo en servicio residuos generados por la actividad humana.…”

Evaluation of concrete production with solid residues obtained from fluidized-bed incineration of MSW-derived solid recovered fuel (SRF)

“…To reduce the release of pollutants, many processes are proposed: the natural weathering of bottom ash (for about 2 months) to promote the carbonation (that involves the absorption of CO 2 , which causes pH decrease and improvement in leaching properties) [24]; different methods to perform an accelerated carbonation [25,26]; the washing of residues with water [18,27] or with chemical solutions [8,28]; the vitrification (at 1450°C) and subsequent crushing of residues [29].…”