D34 FACE THE CHALLENGE

Assertion (A): Fly ash is used in concrete as a partial replacement of cement. Reason (R): Fly ash increases heat of hydration.

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

Answer explanation

Fly ash reduces the heat of hydration and improves long-term strength and workability, making R false.

Which component in a water supply system stores water at a height for pressure and supply?

• Overhead tank
• Pump house
• Sump tank
• Intake well

Answer explanation

Overhead tanks store treated water at elevation to supply it under pressure to users by gravity.

The instrument used to measure vertical angles in surveying is:

• Plane table
• Level
• Theodolite
• Compass

Answer explanation

Theodolite is used to measure both horizontal and vertical angles accurately in surveying.

Assertion (A): Expansion joints are provided in concrete pavements. Reason (R): To allow thermal movement and prevent cracking.

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

Answer explanation

Expansion joints accommodate temperature-induced expansion and contraction, thus preventing cracks in pavements.

Which material is used for making gauges for fine tolerances?

• Cast iron
• Aluminum
• Tool steel
• Wrought iron

Answer explanation

Tool steel is used for making measuring gauges due to its hardness, wear resistance, and ability to retain precision.

Which part of a water supply system removes suspended solids?

• Sedimentation tank
• Chlorination unit
• Aeration tank
• Clear water reservoir

Answer explanation

Sedimentation tanks allow suspended particles to settle by gravity before further treatment.

Standard brickwork is measured in:

• Cubic meter
• Square meter
• Linear meter
• Kilogram

Answer explanation

Brickwork in walls and foundations is measured in cubic meters, considering the volume of brick and mortar.

Which type of roof is suitable for areas with heavy rainfall?

• Flat roof
• Sloped roof
• Terrace roof
• Shell roof

Answer explanation

Sloped roofs facilitate easy drainage of rainwater and are ideal for regions with heavy rainfall.

The strength of concrete increases with:

• Increase in water-cement ratio
• Decrease in cement content
• Proper curing
• Excessive vibration

Answer explanation

Curing ensures continuous hydration of cement, which significantly increases the strength of concrete over time.

Which method is used to estimate irregular plots of land?

• Cross-section method
• Average ordinate method
• Mid-ordinate rule
• Planimeter

Answer explanation

A planimeter is an instrument used to measure the area of irregular shapes directly from maps or drawings.