Concrete Technology

5% of the total aggregates for low workability with a coarse grading ✘ 10% of the total aggregates for low workability with a fine grading ✘ 20% of the total aggregates for a mix having high workability with fine grading ✘ all the above. ✔

desired strength and workability ✘ desired durability ✘ water tightness of the structure ✘ resistance to water ✔ all the above ✔

size and shape of aggregates ✘ specific gravity of aggregates ✘ grading of aggregates ✘ size and shape of the container ✔ none of these ✔

reduces the shrinkage of concrete ✘ preserves the properties of concrete ✘ prevents the loss of water by evaporation ✘ all of the above ✔

2.5 cm ✘ 5.0 cm ✘ 7.5 cm ✘ 10 cm ✔ 15 cm ✔

where B.M. and S.F. are small ✘ where the member is supported by other member ✘ at 18 m apart in huge structures ✘ in concrete wall at sill level of windows ✔ all the above ✔

1/5th of mean dimension ✘ 2/5th of mean dimension ✘ 3/5th of mean dimension ✘ 4/5th of mean dimension ✔ none of these ✔

 1 : 1 : 2

✘

1 : 2 : 4

✘

1:3:6

✘

1:2:8

✔

1:4:1

✔

less liable to segregation ✘ more liable to segregation ✘ more liable to bleeding ✘ more liable for surface scaling in frosty weather ✔ none of these ✔

4.5

✘

5.5

✘

6.5

✘

7.5

✔

8.5

✔