What is best design for concrete mix ASTM?

CONCRETE DESIGN STUDY 

A. Purpose

1) Check that the nominal composition of the concrete proposed by the Contractor enables

the specification to be met.

2) Check that the concrete specifications are still respected if the quality of the ingredients

reaches the specified limits or the probable limits of the ingredients used.

3) Check that the concrete specifications are still respected if the proportions of the

ingredients reach the specified limits or the probable limits resulting from the site

installation (the design limits may also be chosen so as to study several nominal

compositions simultaneously).

B. The design test will involve the following operations:

1) Three batches meeting the nominal formula.

2) Eight batches varying from the nominal formula as follows:

a) Two batches by modifying the proportions of aggregates (for example variation of the

ratio of the mass of coarse aggregates to that of finer aggregates by% in either

direction).

b) Two batches by altering the quantity of mixing water ( l/m³ more and less).

c) Two batches by altering the quantity of cement ( kg/m³ more and less).

d) If an additive or additives are used, two batches by altering the quantity or quantities

of additives (half and double the optimum quantities).

C. Measurements made for concrete classes A, B and C:

1) Each batch shall be the subject of the following measurements:

2) consistency;

3) density and air content within the fresh concrete;

4) density of concrete at days;

5) compressive strength at7 days on three samples;

6) compressive strength at days on three samples and static modulus of elasticity and

Poisson's ratio (in addition to ASTM C strains shall be measured for stresses of3,5,7,

9, MPa).

7) The components shall be subject to the control measurements specified elsewhere.

8) Also to be noted are the following factors:

a) Temperature of the components and of the concrete during the tests.

b) Aspect of the fresh concrete during performance of the consistency test and of the

preparation of the specimens.

c) Aspect of breakage during the mechanical tests.

MR HATEM LABIB , answerd  all correct