Yahya Ghasemi Print III pdf

Shape
Circumsphered edge 
length (a
c
) 
Midsphered edge length 
(a
m
) 
Tetrahedron
4
ݎ
ξ
6
4
ݎ
ξ
2
Cube 
2
ݎ
ξ
3
2
ݎ
ξ
2
Octahedron
2
ݎ
ξ
2
2
ݎ
Dodecahedron
4
ݎ
ξ
3(1 +
ξ
5)
4
ݎ
(3 +
ξ
5)
Icosahedron 
4
ݎ
ඥ
10 + 2 ×
ξ
5
4
ݎ
(1 +
ξ
5)

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29
Mix design approaches
3.4. Concluding remarks
Different approaches in mix design were briefly discussed in the current chapter. It should be 
mentioned that using the models will not necessarily lead to production of acceptable concrete 
in term of required specification of the final product and the recipes usually need fine tuning 
and corrections which is often based on trial batches of concrete. Moreover, some of the 
models may be useable for a specific region or certain type of aggregates, especially the 
models that are focusing on ideal size distribution curves. 
As for the more advanced models like CPM, the number of required input data and the tests 
that are needed to be conducted renders the model as a complex and time consuming 
approach. 
In addition, the models that are based on specific surface area suffer from inaccuracy and 
complexity of conducting specific surface area measurements as there are no commonly 
accepted methods for the tests.
A simple fairly accurate mix design model could potentially reduce the number of tests that 
are needed for using the model and also the number of trail batches can be lowered by a more 
accurate estimation of the properties of the final product. 

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30
Methods
4. METHODS
The current chapter deals with the test methods utilized in the laboratory for obtaining the 
input data to the models in addition to the methods that were used in calculations of the 
models.