title: Increase of the reactivity of densified silica fume by sonication treatment.
abstract: Five silica fumes from different manufacturers were subjected to ultrasonic treatment in order to decrease particle agglomeration and improve particle dispersion. The effectiveness of the sonication was observed as a reduction in particle size distribution of sonicated silica fume (SSF) compared to non-sonicated silica fume. SSF was added to Portland cement, and then the hydrated paste was analysed by thermogravimetric analyses (TGA/DTG) and scanning electron microscopy (SEM/EDX). The results were compared with those of control pastes made with untreated densified silica fume (DSF), as well as a reference cement paste of ordinary Portland cement (OPC). A maximum grade of de-agglomeration by the sonication was obtained, with a high volume of particles of diameter less than 1 μm. Images obtained by transmission electron microscopy (TEM) of the SSF showed sintered particles that could not be fragmented by the treatment. Micro-structural characterisation results showed an increase in the reactivity of the silica fume after the treatment.
authors.affiliation: Instituto de Ciencia y Tecnología del Hormigón (ICITECH), Universitat Politècnica de València, Valencia, Spain. errodnar@disca.upv.es
authors.forename: Erich D
authors.initials: ED
authors.lastname: Rodríguez
authors.forename: Lourdes
authors.initials: L
authors.lastname: Soriano
authors.forename: Jordi
authors.initials: J
authors.lastname: Payá
authors.forename: María Victoria
authors.initials: MV
authors.lastname: Borrachero
authors.forename: José M
authors.initials: JM
authors.lastname: Monzó