Yahya Ghasemi Print III pdf

particles. (Alexander and Mindess, 2005; Neville, 1995). 

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Mix design approaches
3. MIX DESIGN APPROACHES
Mix design can be defined as “the process of choosing the ingredient of concrete and 
determining their quantities with the object of producing as economically as possible of 
certain concrete of certain minimum properties such as consistence, strength, and durability” 
(Neville, 1995). 
During past decades several attempts were made on formulating the mix design. One of the 
most common approaches to mix design is based on the concept of particle packing density
first introduced by Feret (1892). The aim of particle packing density concept is to minimize 
the inter-particle voids between the constituents of concrete in order to reduce the paste 
demand. Packing density is the ratio of the volume of solids to the bulk volume of the solid 
particles (De Larrard, 1999). Several researchers tried to develop Feret’s model further,
research conducted by Powers (1968) on the interaction of different components in mixture 
gave another dimension to the knowledge of particle packing. In 1999, De Larrard (De 
Larrard, 1999) introduced a multi component packing model that included interaction 
between the particles. With the introduction of computers, packing softwares were developed 
to do more detailed and complex calculations for estimation of particle packing, e.g. Europack 
(Idorn, 1995), Rene-LCPC (lcpc.fr), and 4C packing (dti.dk). 
Another approach to maximizing the packing is by means of developing a method to design 
an ideal particle size distribution curve as in the works of Fuller amd Thompson (1907) and
Andreasen and Andersen (1930). Figure 3.1. (adopted form Kumar V and Santhanam, 2003)
shows some of packing models and their relation to each other. The mix design approaches 
are listed in three main categories i.e. ideal curves, models based on packing theory and also 
layer theories. The ideal curve approach can be also categorized under packing theory as they 
eventually change the sieving curve to result in a higher packing. However, since the effect on 
the packing density is implemented indirectly, the ideal curve approaches were listed 
separated from packing theory branch. Moreover, some of the models such as 4C works based 
on combination of ideal curve and packing theory approaches. Under the Multi-phase 
approach branch, models that consider concrete as separated liquid and solid phases are listed. 
More information on each category can be found in Sections 3.1 to 3.3.

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Mix design approaches
Figure 3.1. Mix design approaches 

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Mix design approaches