chapter  15
9 Pages

Performance specifications

In recent years, we have learned how to produce a remarkable range of concrete products: ultra-high strength concrete, self-compacting concretes, corrosion inhibiting concretes, “tough” concretes (with the addition of fibres), and now even sustainable concretes. In fact, we can now largely “tailor-make” concretes for virtually any project. However, in our approach to mixture proportioning, we still rely largely on prescriptive specifications, such as those described in Chapter 14. That is, specifications that generally include requirements such as maximum w/b ratios, minimum cement contents, cement types, limitations on the types and/or amounts of both chemical and mineral admixtures, on the amount of filler material in the cement, and so on. These types of specifications have served us reasonably well in the past, when the cement and concrete industries as a whole were much less sophisticated than they are now. However, such specifications also tend to inhibit the most efficient use of the materials now available to make up a concrete mixture.