3 - High strength concrete

Abstract

This chapter discusses the materials technology underlying the development of high strength concrete, examines the selection of optimum constituent materials and considers the concrete mix design. High Strength Concrete is a relatively recent development in concrete technology made possible by the introduction of efficient water-reducing admixtures and high strength cementitious materials. It should be recognized that there is no single or unique composition for high strength concrete (HSC). HSC can be made with a range of materials and mix designs which produces slightly differing properties. HSC is produced with most available Portland cements. Silica fume is almost ubiquitous in HSC as it has approximately three times the cementing efficiency (on a weight for weight basis) as Portland cement. This facilitates the achievement of high strength without excessive cement contents. To be effective it should always be used in conjunction with a superplasticizer. It is usually incorporated into concrete at 5-15 % by weight of total binder. The role of admixtures is much more significant in HSC than for more conventional concretes. Further, the chapter discusses the material technology of HSC.