Sole of Concrete—Mix Proportion - The Issues and Discussion of Modern Concrete Science - page 18

Step One: Basing on engineering practice, determining what kind of concrete to
use? Stiff concrete, semi-stiff concrete, plastic concrete, or high-performance
concrete.
Under premise of meeting requirements of construction technology, construction
circumstance, structure component dimension, and steel bar intensity, stiff concrete
should be considered with priority, the second is semi-stiff concrete, the third is
plastic concrete, and the last is high-performance concrete.
Step Two: Determining unit weight of concrete.
According to the author

' is experiences, unit weight of stiff concrete is within the

2,550 kg/m 3 , as for semi-stiff concrete is within the range of

range of 2,480

-

2,480 kg/m 3 , and for plastic and high-performance concrete is within the range
of 2,380

2,430

-

2,450 kg/m 3 . Whether the unit weight chosen should be a smaller or bigger
value when doing mix design mainly related to speci

-

c gravity of coarse aggregate.
Step Three: Determining consumption of cementitious material.
Cement consumption of stiff concrete is within the range of 280 330 kg/m 3 ,as

-

360 kg/m 3 , for plastic concrete is for semi-stiff concrete is within the range of 320 -

450 kg/m 3 , and for high-performance concrete is within the within the range of 380 -

500 kg/m 3 .
Step Four: Determining coarse aggregate content.
Coarse aggregate content of stiff concrete iswithin the range of 1,380

range of 450 -

1,450 kg/m 3 ,
as for semi-stiff concrete is 1,330 - 1,380 kg/m 3 , for plastic concrete is 1,250 - 1,350 kg/
m 3 , and for high-performance concrete is 1,000

-

1,300 kg/m 3 .
Having undergone the following four steps, sand ratio and water demand will be

-

fixed with it.
The summary on the above steps is shown in Table 1.4 .

Table 1.4 Material and other details of different mix proportions for C50 concrete
Compared
content

Stiff concrete Semi-stiff

concrete

Plastic
concrete

High-perfor
mance concrete

Slump/mm 0 5 5 15 15 50 150

- - - 以上

Unit weight/
(kg/m 3 )

2,480 2,550 2,430 2,480 2,380 2,450 2,380 2,450

- - - -

Cement con-
sumption/
(kg/m 3 )

280 - 330 320 - 360 380 - 450 450 - 500

Coarse
aggregate
content/
(kg/m 3 )

1,380 - 1,450 1,330 - 1,380 1,250 - 1,350 1,000 - 1,300

Application Airport runway,

wharf, high grade
highway, precast
structural compo-
nent, plain concrete
with bulky volume
and so on

Ordinary
highway,
municipal
roads, park-
ing ports and
so on

Reinforced
concrete con-
structed by
crane and
small cart and
so on

Concrete con-
structed in cir-
cumstances of
pumping and
commercial
concrete