Title: Durability of DSP Mortars Exposed to Conditions of Wetting and Drying

Author(s): D. A. St. John; L. C. McLeod; and Neil B. Milestone

Publication: Symposium Paper

Volume: 159

Issue:

Appears on pages(s): 45-56

Keywords: alkali-aggregate reactions; petrography; silica fume; Materials Research

DOI: 10.14359/1395

Date: 2/1/1996

Abstract:
DSP mortar bars used to measure volume changes as a result of exposure to wetting and drying have expanded and failed. Petrographic investigation showed that the failures have occurred due to alkali-aggregate reaction of undispersed agglomerates of silica fume. Investigation of the particle size ranges and dispersiblity of a range of silica fumes showed that they were all agglomerated to varying degrees and that the dispersibility is dependent on source and age of the silica fume. It is concluded that unless silica fume can be adequately dispersed in DSP materials there will be a potential for alkali-aggregate reaction to occur where the exposure conditions involve wetting and drying.