27 real Concrete Technology questions from the Civil Design & Codes bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What is Target mean strength?
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A.flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
B.IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
C.high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
D.mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
A.Target mean strength — flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
B.Target mean strength — IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure
C.Target mean strength — IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
D.Target mean strength — IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
A.IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure
B.flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
C.IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
D.IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
5. Which term means: "IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand"?
A.Fine aggregate zones — high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
B.Fine aggregate zones — IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
C.Fine aggregate zones — mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
D.Fine aggregate zones — flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
8. Which term means: "IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure"?
A.Durability requirements by exposure — IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
B.Durability requirements by exposure — mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
C.Durability requirements by exposure — flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
D.Durability requirements by exposure — IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure
A.IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
B.high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
C.limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections
D.IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
11. Which term means: "high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes"?
A.Superplasticizer — limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections
B.Superplasticizer — high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
C.Superplasticizer — mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
D.Superplasticizer — IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
A.flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
B.IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure
C.high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
D.IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
14. Which term means: "IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather"?
A.Minimum curing period — flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
B.Minimum curing period — IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
C.Minimum curing period — mean of four consecutive cube results must be at least fck + 0.825 S or fck + 3, and no individual result may fall below fck − 3 for M20 and above
D.Minimum curing period — IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
A.IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
B.mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
C.limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections
D.high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
17. Which term means: "limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections"?
A.Maximum cement content — IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
B.Maximum cement content — IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure
C.Maximum cement content — limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections
D.Maximum cement content — mean of four consecutive cube results must be at least fck + 0.825 S or fck + 3, and no individual result may fall below fck − 3 for M20 and above
A.IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
B.IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
C.mean of four consecutive cube results must be at least fck + 0.825 S or fck + 3, and no individual result may fall below fck − 3 for M20 and above
D.high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
20. Which term means: "mean of four consecutive cube results must be at least fck + 0.825 S or fck + 3, and no individual result may fall below fck − 3 for M20 and above"?
A.Acceptance criteria for strength — mean of four consecutive cube results must be at least fck + 0.825 S or fck + 3, and no individual result may fall below fck − 3 for M20 and above
B.Acceptance criteria for strength — limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections
C.Acceptance criteria for strength — IS 10262:2019 sets f′ck as the higher of fck + 1.65 S and fck + X, with S of 4 for M20 to M25 and 5 for M30 to M55
D.Acceptance criteria for strength — IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
A.IS 456 Table 5 caps water-cement ratio at 0.55, 0.50, 0.45, 0.45 and 0.40 and sets minimum grades M20 to M40 from mild to extreme exposure
B.mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
C.IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
D.IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
23. Which term means: "mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone"?
A.High-performance concrete — high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
B.High-performance concrete — IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
C.High-performance concrete — mean of four consecutive cube results must be at least fck + 0.825 S or fck + 3, and no individual result may fall below fck − 3 for M20 and above
D.High-performance concrete — mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
A.limited to 450 kg/m³ excluding fly ash and GGBS, to control heat of hydration, shrinkage and thermal cracking in thick sections
B.flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
C.IS 456 requires at least 7 days of moist curing for OPC and 10 days for blended cements, extended to 14 days in hot and dry weather
D.mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
26. Which term means: "flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content"?
A.Self-compacting concrete — IS 383 grades sand into Zones I to IV by sieve passing, Zone I being coarsest and Zone IV finest, and permits manufactured sand
B.Self-compacting concrete — high-range water reducer such as PCE or SNF conforming to IS 9103 that cuts water by 20 percent or more at equal workability, enabling low w/c pumpable mixes
C.Self-compacting concrete — flows and fills formwork under its own weight without vibration, with slump flow 550 to 850 mm, controlled by viscosity modifying admixture and high powder content
D.Self-compacting concrete — mix with water-binder ratio near 0.30 using silica fume or GGBS and PCE, specified for low permeability and chloride resistance rather than strength alone
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