Modern concrete mixtures are designed to fulfill many functions on a project. Traditionally, engineers are most concerned with the compressive strength for design purposes and contractors are most concerned with slump for placement reasons.
As concrete technology continues to develop, the use of modern concrete mixtures become more intricate and complicated, as other engineering properties are specified and new materials are available to help meet those engineering performance characteristics. Recent developments in chemical admixtures and supplementary cementitious materials (SCMs) can help solve many problems when these new materials are used properly. Sometimes these developments can conflict with one another, or new materials may interact in unpredictable ways, which can place a contractor in unfamiliar territory. To avoid problems with concrete placements, and to take advantage of what new technology may have to offer, it helps to know what to expect when working with modern concrete mixtures and how they impact the concrete contractor.
Matthew D'Ambrosia, Materials Consulting, authored this October 2012 Concrete Construction article.