Building Materials, Third Edition

QPV f2w—

—

186 liter (kg), and the sand content 35 per cent of the absolute volume of total aggregates
(Table 11.9). The cement content will therefore be:

186
0.45 = 413.3 kg.
The mix will require necessary correction in the ratio of fine aggregate to total aggregates
due to a change in the water-cement ratio to 0.45 as against 0.6 assumed (Table 11.10). Similarly
a correction may be necessary in the water content per m^3 of

Hence, total water to be added = 186 + 5.58 [(186 × 3/100 = 5.58)]
= 191.58 lit (kg)
This will need a change in the cement content to keep the water-cement ratio constant.
Hence, cement content per m^3 will be

191.58

0.45 = 425.73 kg/m

(^3).
As in the case of water-cement ratio, the cement content thus calculated has to be checked
against the requirements of durability under various conditions of exposure during the life of
the structure (Table 11.1) and the greater of the two values should be adopted.

p2—2g—2e—2g

After obtaining the cement content, the water content and the percentage of fine aggregate to
total aggregate in terms of absolute volume, the quantities of fine and coarse aggregate are
calculated from the equations given below:

for fine aggregate

V =







1 1

100

a

c fa

C f

W

SpS

„—˜"2II    IH e-

22†—"22‡—2g2—2ƒ—2€™—2

g22—222„—˜"2II W

g—22™ e%

    2<

2

    

!—22„—˜!2II#W —2™   —22—!2——

p2—2™

-



2—

2<2ID2 H CIS22™22<2s

sss22<2s†2 'IS22™22<2sss

sƒX2QVQ'IWUH 'QH22™22<2s†

s™—22™—2

2 >2Q22™ H

—

22™-—™



—™2˜"2HI

i—™2HHS2

™—2 H >2I22™

™—2

227—E

™-2—



p22—— 'IS2?G-Q 'U22™

ƒ  

™X2sƒX2IHPTP+IWVP