A Mix Performance Method for High Performance Concrete
This chapter presents theoretical or semi-empirical mix design tools. The LCPC Experimental Method is a practical normal strength mix design method. The chapter deals with the problem of high strength concrete (HSC) composition. An empirical formula is presented that allows the prediction of strength, together with a theoretical workability model. HSC can be obtained with high performance cements, admixtures and supplementary cementitious materials such as silica fume. Using the Farris model for the composition of HSC, it will be considered that the three solid components (coarse aggregate, sand and cement) represent an interlocking of three classes of grains, in accordance with the hypothesis. A theoretical model and an empirical formula have been presented, from which a practical mix design method is proposed. The formula allows us to understand the real action of silica fume in HSC: the filler effect shown by the lowering of the water/cement ratio, and the pozzolanic effect, expressed by the contribution of the s/c term.