The effect of peat and wood fly ash on the porosity of mortar

• Published in: Construction & building materials Vol. 223; pp. 421 - 430
• Main Authors: Rissanen, Jouni, Giosué, Chiara, Ohenoja, Katja, Kinnunen, Paivo, Marcellini, Mirco, Letizia Ruello, Maria, Tittarelli, Francesca, Illikainen, Mirja
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.10.2019
• Subjects: Biomass fly ash; Capillary water absorption; Drying shrinkage; Fluidized bed combustion; Porosity; Water vapor permeability; Biomass fly ash; Capillary water absorption; Porosity; Fluidized bed combustion; Drying shrinkage; Water vapor permeability
• ISSN: 0950-0618; 1879-0526
• DOI: 10.1016/j.conbuildmat.2019.06.228

•Fluidized bed combustion fly ashes (FBCFAs) from wood and peat were studied.•FBCFAs increased the porosity and capillary water absorption of mortar.•Mortars prepared with FBCFA exhibit comparable compressive strength to those containing coal fly ash.•FBCFAs outperformed unreactive limestone filler. Fluidized bed combustion fly ash (FBCFA), notably different from regular (coal) fly ash, is a promising industrial side stream to be used as a supplementary cementitious material (SCM). Peat and wood are important sources of biomass for energy production in Nordic countries and generate formidable amounts of un-used ash yearly. Two FBCFAs from the co-combustion of peat and wood, fly ash from coal combustion, and limestone filler were used to replace 10 wt%, 20 wt%, and 40 wt% of cement in mortar specimens. The compressive strength, porosity, water absorption, water vapor permeability, and drying shrinkage of the mortars were measured and compared. It was found that in almost all properties FBCFAs outperformed un-reactive limestone filler. Compared to coal fly ash, FBCFAs produced mortars with comparable compressive strength although with higher porosity, water absorption, and water vapor permeability.