MCQs on Ingredients of Concrete
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Q91: Fly ash reduces the quantity of water requirement by
Difficulty: Medium
Correct Answer: C. 3 to 5 per cent
Solution:
Fly ash particles are spherical (ball-bearing effect) and react as a pozzolan. The spherical shape reduces inter-particle friction and improves the flow of concrete, reducing water requirement by approximately 3 to 5 percent compared to a plain OPC mix at the same workability.
Solution:
Fly ash particles are spherical (ball-bearing effect) and react as a pozzolan. The spherical shape reduces inter-particle friction and improves the flow of concrete, reducing water requirement by approximately 3 to 5 percent compared to a plain OPC mix at the same workability.
Q92: The fineness modulus of coarse sand is
Difficulty: Medium
Correct Answer: D. 2.9 to 3.2
Solution:
Coarse sand has a fineness modulus in the range of 2.9 to 3.2. This range corresponds to Zone I grading (coarsest sand) as per IS 383. Zone II sand (medium-coarse) has FM around 2.6-2.9.
Solution:
Coarse sand has a fineness modulus in the range of 2.9 to 3.2. This range corresponds to Zone I grading (coarsest sand) as per IS 383. Zone II sand (medium-coarse) has FM around 2.6-2.9.
Q93: The property of aggregate which resists abrasive effect of hard particles or mechanism is known as
Difficulty: Easy
Correct Answer: B. abrasion resistance
Solution:
Abrasion resistance is the specific property of aggregate that measures its ability to resist surface wear from rubbing, scraping, or grinding by hard particles. It is distinct from toughness (resistance to impact) and hardness (resistance to scratching/indentation).
Solution:
Abrasion resistance is the specific property of aggregate that measures its ability to resist surface wear from rubbing, scraping, or grinding by hard particles. It is distinct from toughness (resistance to impact) and hardness (resistance to scratching/indentation).
Q94: The quality of concrete can be improved by using
Difficulty: Easy
Correct Answer: C. graded aggregates
Solution:
Using graded aggregates (a combination of different particle sizes following a specific grading curve) reduces voids, minimises cement paste requirement, improves workability, and increases the density and durability of concrete.
Solution:
Using graded aggregates (a combination of different particle sizes following a specific grading curve) reduces voids, minimises cement paste requirement, improves workability, and increases the density and durability of concrete.
Q95: The rocks which have very high strength are
Difficulty: Medium
Correct Answer: D. granite
Solution:
Granite is an igneous rock with very high compressive strength (typically 150-280 MPa), making it the strongest common building rock. It is used as a high-quality aggregate in concrete requiring superior strength and abrasion resistance.
Solution:
Granite is an igneous rock with very high compressive strength (typically 150-280 MPa), making it the strongest common building rock. It is used as a high-quality aggregate in concrete requiring superior strength and abrasion resistance.