,

.7)

where R-strength of concrete; C/W–cement-water ratio;

K-coefficient.

After treatment of experimental researches B.Skramtaev and

Y.Bagenov offered the formulas of concrete strength :

If C/W≥2.5

R = АRc (C / W − 0 5

. )

,

(4.8)

If C/W≤2.5

R = А R

+

1

c (C / W

)

5

.

0

(4