Title:
Silica Fume in a Concrete Specification: Prescribed, Permitted, or Omitted?
Author(s):
Adam M. Neville
Publication:
Concrete International
Volume:
23
Issue:
3
Appears on pages(s):
73-77
Keywords:
DOI:
Date:
3/1/2001
Abstract:
Confusion and costly mistakes can result when the terms used in a specification are not clearly defined. Designers are given the task of designing structures that fulfill the owner’s requirements at an economic cost, and this is a difficult task to complete when the intention behind the specification is not explicit. Recent performance-type specifications do not always prescribe mixture ingredients and proportions in detail, particularly when these ingredients are potentially beneficial but not absolutely required. Silica fume began to be used as a pozzolan in the 1970s, but currently standards for silica fume are slow to appear. Terminology used to describe the role of silica fume in concrete is inconsistent, and silica fume is not categorized uniformly. Silica fume should be included in the total cementitious materials whose mass is counted for the purpose of establishing the cement content of the concrete and its water-cement ratio; likewise, it is essential for the specification to state whether the silica fume can be used with other materials and, if so, in what proportions.