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Addition of bottom ash from biomass in calcium silicate masonry units for use as construction material with thermal insulating properties

Abstract:

This paper studies the effect of adding bottom ash from the combustion process of biomass plants to calcium-silicate samples for use as construction material with thermal insulating properties. After a process of physical, chemical and mineralogical characterization of the raw materials, calcium-silicate samples were manufactured by mixing bottom ash (CF) with different sources of lime (calcium oxide-OC and calcium hydroxide-HC) and Portland cement (CM). The amount of bottom ash added ranged from 10% to 90% of the dry weight of the mixtures. The experimental program included a wide range of testing methods of the developed material such as water absorption, mechanical strength, porosity, microstructure, freeze-thaw and thermal conductivity. The optimal values are those containing a 1:1 ratio of SiO 2/CaO, with compressive strength ranging from 25.21 MPa (CF/HC) to 61.11 MPa (CF/CM) and thermal conductivity from 0.564 W/m K (CF/OC) to 0.773 W/m K (CF/HC). The initial results obtained make it possible in principle to obtain calcium-silicate samples with low thermal conductivity according EN standard 771-2:2011. © 2013 Elsevier Ltd. All rights reserved.