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Practice SetConcrete Technology & RCC

Concrete Technology & RCC MCQ Practice Set — 25 Questions with Answers

25 exam-oriented Concrete Technology & RCC multiple-choice questions with the correct answer and a clear explanation for each. Frequently asked in Civil Engineering (Shared). Solve the full set below for free — no login required.

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  1. 1
    Design aidsMEDIUM

    Limiting moment coefficients such as 0.138 fckbd2 for Fe415 are derived from:

    ANominal cover table
    BLimit state stress block and xu,max/d
    CWater-cement ratio
    DFormwork table

    Answer: B. Limit state stress block and xu,max/d

    Explanation: These coefficients arise from stress block parameters and limiting neutral-axis ratios. Reference: Clause 38.1 / Annex G | Page: verify from your official BIS copy/PDF pagination Last-Minute Revision Checklist Memorise durability exposure classes and cover values: mild 20 mm, moderate 30 mm, severe 45 mm, very severe 50 mm, extreme 75 mm. Memorise LSM factors: concrete 1.5, steel 1.15, design steel stress 0.87fy. Memorise load combinations: 1.5(DL+LL), 1.2(DL+LL+WL/EL), 1.5(DL+WL/EL), 0.9DL+1.5W

  2. 2
    Table 26MEDIUM

    Table 26 provides:

    ADesign bond stress values
    BPartial load factors
    CConcrete exposure classes
    DFormwork times

    Answer: A. Design bond stress values

    Explanation: Table 26 is essential for development length and anchorage calculations. Reference: Table 26 | Page: verify from your official BIS copy/PDF pagination

  3. 3
    Table 19MEDIUM

    Table 19 provides:

    ADesign shear strength of concrete tau_c
    BNominal cover
    CCuring period
    DConcrete grades

    Answer: A. Design shear strength of concrete tau_c

    Explanation: Table 19 is used for shear design and depends on percentage steel and concrete grade. Reference: Table 19 | Page: verify from your official BIS copy/PDF pagination

  4. 4
    Table 3MEDIUM

    Table 3 of IS 456 is associated with:

    ASteel grades
    BEnvironmental exposure conditions
    CShear stress values
    DLoad factors

    Answer: B. Environmental exposure conditions

    Explanation: Table 3 classifies exposure environments for durability design. Reference: Table 3 | Page: verify from your official BIS copy/PDF pagination

  5. 5
    Maximum shearMEDIUM

    If nominal shear stress exceeds tau_c,max, the correct action is to:

    AIgnore shear
    BReduce cover only
    CIncrease section size or grade/redesign
    DProvide unlimited stirrups only

    Answer: C. Increase section size or grade/redesign

    Explanation: Concrete diagonal compression capacity limits shear; reinforcement cannot compensate beyond tau_c,max. Reference: Clause 40.2.3 | Page: verify from your official BIS copy/PDF pagination

  6. 6
    Critical section bendingMEDIUM

    For isolated footing, bending moment is generally checked at:

    AFace of column/pedestal/wall
    BEdge of footing only
    CCentre of footing only
    Dd/2 from edge

    Answer: A. Face of column/pedestal/wall

    Explanation: Critical section for bending in footing is usually at face of column or wall. Reference: Clause 34.2.3 | Page: verify from your official BIS copy/PDF pagination

  7. 7
    Tie diameterMEDIUM

    Diameter of lateral ties should not be less than one-fourth of largest longitudinal bar diameter and not less than:

    A4 mm
    B6 mm
    C12 mm
    D10 mm

    Answer: B. 6 mm

    Explanation: Minimum tie diameter ensures adequate restraint to longitudinal bars. Reference: Clause 26.5.3.2 | Page: verify from your official BIS copy/PDF pagination

  8. 8
    Main bar spacingMEDIUM

    Maximum spacing of main reinforcement in slabs should not exceed:

    A2d or 200 mm
    B3d or 300 mm, whichever is less
    C16 phi or 300 mm
    D5d or 450 mm

    Answer: B. 3d or 300 mm, whichever is less

    Explanation: Main slab bars are limited to 3d or 300 mm to control cracking and distribution. Reference: Clause 26.3.3 / 26.5.2 | Page: verify from your official BIS copy/PDF pagination

  9. 9
    Lap Splice LocationMEDIUM

    Lap splices in flexural reinforcement should preferably be avoided at sections where the bar stress is:

    AMaximum
    BZero only
    CAlways compressive in every layer
    DUnrelated to bending

    Answer: A. Maximum

    Explanation: Lap splices are avoided at high-stress regions and staggered where possible.

  10. 10
    Lap splicesMEDIUM

    Lap splices are generally not used for bars larger than:

    A25 mm
    B12 mm
    C36 mm
    D20 mm

    Answer: C. 36 mm

    Explanation: IS 456 restricts lap splices for large bars; welding or mechanical connections are preferred. Reference: Clause 26.2.5.1 | Page: verify from your official BIS copy/PDF pagination

  11. 11
    Deformed barsMEDIUM

    For deformed bars, design bond stress may be increased by:

    A25 percent
    B100 percent
    C10 percent
    D60 percent

    Answer: D. 60 percent

    Explanation: IS 456 permits 60 percent increase in bond stress for deformed bars conforming to relevant standards. Reference: Clause 26.2.1.1 | Page: verify from your official BIS copy/PDF pagination

  12. 12
    Stirrup spacingMEDIUM

    Maximum spacing of vertical shear reinforcement in beams should not exceed:

    A16 times bar diameter only
    B5d or 450 mm
    C0.75d or 300 mm, whichever is less
    Dd or 600 mm, whichever is greater

    Answer: C. 0.75d or 300 mm, whichever is less

    Explanation: Stirrups should be close enough to intercept potential diagonal cracks. Reference: Clause 26.5.1.5 | Page: verify from your official BIS copy/PDF pagination

  13. 13
    Minimum shear formulaMEDIUM

    Minimum shear reinforcement relation in IS 456 is:

    Atau_v = Mu/bd
    BAsc = 0.8% Ag
    CAst/bd = 0.85/fy
    DAsv/(b sv) >= 0.4/(0.87 fy)

    Answer: D. Asv/(b sv) >= 0.4/(0.87 fy)

    Explanation: IS 456 gives minimum shear reinforcement through Asv, spacing, web width and steel grade. Reference: Clause 26.5.1.6 / 40.3 | Page: verify from your official BIS copy/PDF pagination

  14. 14
    M20 maximum shearMEDIUM

    For M20 concrete, tau_c,max is approximately:

    A3.5 N/mm2
    B1.2 N/mm2
    C2.8 N/mm2
    D5.0 N/mm2

    Answer: C. 2.8 N/mm2

    Explanation: IS 456 Table 20 gives tau_c,max for M20 as about 2.8 N/mm2. Reference: Clause 40.2.3; Table 20 | Page: verify from your official BIS copy/PDF pagination

  15. 15
    Effective spanMEDIUM

    For simply supported beams/slabs, effective span is generally the lesser of:

    AClear span plus effective depth and centre-to-centre support distance
    BOnly centre-to-centre of supports
    CClear span and overall depth
    DOverall length and support width

    Answer: A. Clear span plus effective depth and centre-to-centre support distance

    Explanation: IS 456 defines effective span using clear span plus effective depth, limited by centre-to-centre support distance. Reference: Clause 22.2 | Page: verify from your official BIS copy/PDF pagination

  16. 16
    Neutral axisMEDIUM

    Limiting xu/d for Fe415 steel is:

    A0.87
    B0.48
    C0.53
    D0.46

    Answer: B. 0.48

    Explanation: For Fe415 grade reinforcement, the limiting neutral-axis depth ratio is 0.48. Reference: Clause 38.1; Annex G / design aids | Page: verify from your official BIS copy/PDF pagination

  17. 17
    RemovalMEDIUM

    Vertical formwork to columns, walls and beams may generally be removed after:

    A7 days
    B16 to 24 hours
    C21 days
    D3 days

    Answer: B. 16 to 24 hours

    Explanation: IS 456 gives typical minimum stripping time for vertical formwork as 16-24 hours. Reference: Clause 11.3; Table 11 | Page: verify from your official BIS copy/PDF pagination

  18. 18
    CuringMEDIUM

    Minimum curing period for ordinary Portland cement concrete is generally:

    A7 days
    B1 day
    C28 days
    D3 days

    Answer: A. 7 days

    Explanation: IS 456 specifies a minimum curing period of 7 days for OPC concrete under ordinary conditions. Reference: Clause 13.5.1 | Page: verify from your official BIS copy/PDF pagination

  19. 19
    RCC durabilityMEDIUM

    For extreme exposure in RCC, the maximum free water-cement ratio is generally:

    A0.45
    B0.50
    C0.60
    D0.40

    Answer: D. 0.40

    Explanation: Extreme exposure requires the most stringent w/c ratio among common exposure classes. Reference: Clause 8; durability table for RCC | Page: verify from your official BIS copy/PDF pagination

  20. 20
    RCC durabilityMEDIUM

    For mild exposure in reinforced concrete, the maximum free water-cement ratio is generally:

    A0.45
    B0.40
    C0.55
    D0.50

    Answer: C. 0.55

    Explanation: For mild exposure RCC, IS 456 durability table gives maximum free w/c ratio of 0.55. Reference: Durability Table for RCC: Clause 8; Table 5 in many prints | Page: verify from your official BIS copy/PDF pagination

  21. 21
    Durability factorsMEDIUM

    Durability of concrete is most directly improved by:

    AHigh water-cement ratio
    BAdequate cover, low permeability and proper curing
    CRemoving all reinforcement
    DUsing unwashed aggregates

    Answer: B. Adequate cover, low permeability and proper curing

    Explanation: Dense, well-cured concrete with proper cover and controlled w/c ratio improves durability. Reference: Clause 8.1, 8.2 | Page: verify from your official BIS copy/PDF pagination

  22. 22
    ExposureMEDIUM

    Concrete surfaces exposed to sea water spray and alternate wetting/drying are generally classified as:

    AModerate
    BNo exposure
    CMild
    DVery severe / extreme depending condition

    Answer: D. Very severe / extreme depending condition

    Explanation: Marine splash and alternate wetting/drying conditions require higher durability protection. Reference: Clause 8.2; Table 3 | Page: verify from your official BIS copy/PDF pagination

  23. 23
    CreepMEDIUM

    Creep coefficient is generally higher when concrete is loaded at:

    AOnly after 28 days
    BEarlier age
    CAfter 1 year only
    DLater age

    Answer: B. Earlier age

    Explanation: Younger concrete creeps more; IS 456 gives higher creep coefficient for earlier age of loading. Reference: Clause 6.2.5.1 | Page: verify from your official BIS copy/PDF pagination

  24. 24
    Modulus of elasticityMEDIUM

    The approximate modulus of elasticity of M20 concrete by IS 456 expression is:

    A22,360 N/mm2
    B31,623 N/mm2
    C25,000 N/mm2
    D10,000 N/mm2

    Answer: A. 22,360 N/mm2

    Explanation: Ec = 5000 sqrt(20) = about 22,360 N/mm2. Reference: Clause 6.2.3.1 | Page: verify from your official BIS copy/PDF pagination

  25. 25
    Modulus of elasticityMEDIUM

    As per IS 456 expression, the short-term static modulus of elasticity of concrete is:

    AEc = 5000 sqrt(fck)
    BEc = 500 sqrt(fck)
    CEc = 5700 sqrt(fck)
    DEc = 0.7 fck

    Answer: A. Ec = 5000 sqrt(fck)

    Explanation: IS 456 gives Ec = 5000 sqrt(fck), where fck is in N/mm2. Reference: Clause 6.2.3.1 | Page: verify from your official BIS copy/PDF pagination

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