During lime concreting in foundation if kankar lime is used 0.35 cu m of kanakar lime shall be used with 20 cu m ballast and no surkhi or sand or cinder shall be added.

During lime concreting in foundation fine aggregate shall be of surkhi or sand or cinder as specified, and clean and free from dust, dirt, and foreign matters.

A

True

B

False

During lime concreting in foundation the concrete shall consists of 10 cu m of brick ballast, 0.92 cu m of surkhi and 0.6 cu m of white lime in the proportion of 100:32:16 by volume.

A

True

B

False

During lime concreting in foundation coarse aggregate shall be of hard, well-burnt or over-burnt brick ballast of __________ mm gauge.

A

80 mm

B

10 mm

C

40 mm

D

3mm

Statement (I): Lime-surkhi mortar is used in construction of Anicuts (dams) since the 19th century. Statement (II): Portland cement is a recent material compared to surkhi-mortar which is best suited for hydraulic structures.

A

Both Statement (I) and Statement (II) are individually true; and Statement (II) is the correct explanation of Statement (I)

B

Both Statement (I) and Statement (II) are individually true; but Statement (II) is NOT the correct explanation of Statement (I)

C

Statement (I) is true; but Statement (II) is false

D

Statement (I) is false; but Statement (II) is true.

Statement I): Incrustation of sand occurs in rapid sand filter when water softened by lime-soda is fed in for filtration. Statement II): The sand gets coated with precipitates of Ca(OH)2 and Mg(OH)2 generated during softening of water by lime-soda process which leads to incrustation of sand.

A

Both Statement I) and Statement II) are individually true and Statement II) is the correct explanation of Statement I)

B

Both Statement I) and Statement II) are individually true but Statement II) is not the correct explanation of Statement I)

C

Statement I) is true but Statement II) is false

D

Statement I) is false but Statement II) is true

Consider the following related to sand in mortars: 1. It increases the volume of the mortar mix. 2. It increase the strength of masonry. 3. The cost of the mortars is reduced. 4. Shrinkage of the mortar is almost prevented. 5. Surkhi can replace sand in cement mortar used in plastering and this modified mortar is more durable. Which of the above are relevant to ‘sand’ in mortar?

A

1, 2, 4 and 5

B

1, 3 and 4 only

C

3, 4 and 5 only

D

2, 3 and 4 only

Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.Reason R: The sand used in slow sand filters is finer than that in rapid sand filtersSelect your answer based on the coding system given below:

A

Both A and R is true and R is the correct explanation of A

B

Both A and R is true but R is not the correct explanation of A

C

A is true but R is false

D

A is false but R is true

Assertion A: Slow sand filters are more efficient in removal of bacteria than rapid sand filters.
Reason R: The sand used in slow sand filters is finer than that in rapid sand filters
Select your answer based on the coding system given below:

A

Both A and R is true and R is the correct explanation of A

B

Both A and R is true but R is not the correct explanation of A

C

A is true but R is false

D

A is false but R is true

The following are certain operating problems of a rapid sand filter: 1. Sand depth should never be depleted by more than 10 cm. 2. Air binding results due to development of negative head and formation of air bubbles in the filter sand. 3. Water softening with lime-soda leads to incrustation of sand. 4. Bumping of filter bed is caused due to negative head. Which of the above statements are correct?

A

1, 2 and 4 only

B

1, 2 and 3 only

C

3 and 4 only

D

1, 2, 3 and 4

Which of the following statements are correct pertaining to the value of uniformity coefficient Cu for filter sand? (1) For slow sand filters, Cu = 1.8 to 2.5 (2) For rapid sand filters, Cu = 1.3 to 1.7 (3) For slow sand filters, Cu = 1.3 to 1.7 (4) For rapid sand filters, Cu = 1.8 to 2.5

A

2 and 3

B

1 and 4

C

3 and 4

D

1 and 2

During lime concreting in foundation if kankar lime is used 0.35 cu m of kanakar lime shall be used with 20 cu m ballast and no surkhi or sand or cinder shall be added.

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