,

C

15

.

0

(9.5)

evp

−

Where C is quantity of cement.

Density of mortar part of lightweight concrete can be reduced by its

porisation due to adding of air-entraining admixture. Required air content

(V ) in % to transformation of mortar with density ρ to ρ'

can be found

air

m

m

from condition:

100ρ′

V

= 100

m

−

(9