Structure of Portland Cement Pastes Blended with Sonicated Silica Fume

Application of power ultrasound to enhance dispersion of commercial densified silica fume leads to increased compressive strengths and refinement of the pore structure in mortars, compared with those that are untreated. This was attributed to the enhanced pozzolanic reactivity achieved by particle dispersion through sonication, leading to higher consumption of portlandite during curing, and formation of a calcium silicate hydrate gel with a higher degree of cross-linking than is identified in specimens with densified silica fume. This suggests that with the use of sonicated silica fume, it is possible to reduce the required quantity of admixture in blended cements to achieve specified performance, with the additional advantage of the formation of a highly densified structure and refined pore network, contributing to potential improvements in durability. DOI: 10.1061/(ASCE)MT.1943-5533.0000502. (C) 2012 American Society of Civil Engineers.