Graphical Method of Concrete Mix Design

Abstract

The current research work caters for the possibility of arriving at a method for designing concrete mixes (job mix) using locally available materials by means of three prescribed properties of the mix as design pre-requisites, that is water content, water : cement ratio and aggregate : cement ratio of wide ranges to cover a good variety of practical mixes. The above mentioned three prescribed properties can be represented in a graphical solution manner using a trilinear diagram depending on the fact that the absolute volume of the concrete mixture consisting of three materials, cement, water and aggregate is the sum of absolute volumes of the three materials. As a result and from this representation a quadrilateral area can be formed which should include a wide range of mixes having all the prescribed properties mentioned above. The current work will consider the following main influencing parameters on the job mix:1.Water : cement ratios between 0.35-0.84.2.Maximum aggregate sizes of 20 and 12.7 mm.3.Fine aggregate ranges of fine, medium and coarse (B.S 882-1992 [11])4.Aggregate : cement ratios between 3.8-7.6.