title: Fly and bottom ashes from biomass combustion as cement replacing components in mortars production: rheological behaviour of the pastes and materials compression strength.
abstract: In the present research mortar pastes obtained by replacing a commercial cement with the equivalent mass of 5, 10, 20 and 30 wt.% of fly ash or bottom ash from fir chips combustion, were prepared and rheologically characterized. It was observed that the presence of ash modifies their rheological behaviour with respect to the reference blend due to the presence, in the ashes, of KCl and K2SO4 which cause precipitation of gypsum and portlandite during the first hydration stages of the pastes. Hydrated materials containing 5 wt.% of ash display compression strength and absorption at 28 d of same magnitude as the reference composition; conversely, progressive increase of ash cause a continuous decline of materials performances. Conversely, samples tested after 180 d display a marked decline of compression strength, as a consequence of potassium elution and consequent alkali-silica reaction against materials under curing.
authors.affiliation: Università di Udine, Dipartimento di Chimica, Fisica e Ambiente, Via del Cotonificio 108, 33100 Udine, Italy. stef.maschio@uniud.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Maschio
authors.forename: Gabriele
authors.initials: G
authors.lastname: Tonello
authors.forename: Luciano
authors.initials: L
authors.lastname: Piani
authors.forename: Erika
authors.initials: E
authors.lastname: Furlani
mesh_terms: D018533:Biomass; D017610:Calcium Compounds / Q000737:chemistry; D002133:Calcium Sulfate / Q000737:chemistry; D060729:Coal Ash / Q000737:chemistry*; D019245:Compressive Strength; D003252:Construction Materials; D017745:Incineration; D010087:Oxides / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D014783:Viscosity
chemical_list: D017610:Calcium Compounds; D060729:Coal Ash; D010087:Oxides; D012822:Silicon Dioxide; C016538:lime; D002133:Calcium Sulfate