Abstract
Biomass ash is a solid waste generated in large quantities in stand-alone boilers for the generation of power and heat. The cocoa industry, which uses cocoa almond bark (20%) and eucalyptus wood (80%) as fuel, generates fly and bottom ash. The fact that the properties of the ash are little known limits its correct provision and application. In this paper, bottom ash ("fornalha") and fly ash ("ciclone") were collected during the boiler cleaning process, and characterized by their chemical composition, morphology (SEM), particle size and mineralogy (DR-X) in order to assess the potential use of the ash as mineral addition. The ash was treated by grinding and controlled burning at 500, 700 and 900o C. To evaluate the effect of ash, four mortars were cast with 5% cement with fly ash and bottom ash replacement, in natura and ground. The results of water absorption and mechanical strength (compression and tension in flexion) tests showed increased absorption and porosity in all mixtures, but unchanged mechanical properties for mortar with ground fly ash, compared with mortar without addition. This demonstrates that this kind of ash has potential as mineral addition.
Keywords:
Boiler ash; Cement replacement addition; Mortar
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