All Free Civil Engineering MCQs with Answers

• A. Hydration of cement compounds
• B. Evaporation of mixing water
• C. Oxidation of aggregate particles
• D. Carbonation of fresh mortar

Explanation: Hydration is the chemical reaction between cement compounds and water. It forms binding products and releases heat, while evaporation…

• A. Tricalcium silicate
• B. Dicalcium silicate
• C. Tricalcium aluminate
• D. Tetracalcium aluminoferrite

Explanation: Dicalcium silicate hydrates more slowly and contributes substantially to later-age strength.

• A. Very dry and zero-slump
• B. Highly fluid and self-levelling
• C. Plastic and cohesive
• D. Already hardened and set

Explanation: The slump test is commonly used for fresh concrete with plastic consistency.

• A. Higher permeability and lower durability
• B. Lower cement hydration and faster setting
• C. Higher bleeding and lower strength
• D. Lower permeability and higher durability

Explanation: A lower water-cement ratio usually leaves fewer connected capillary pores after hydration.

• A. Lost its plasticity and gained substantial rigidity
• B. Just begun to lose its fluidity
• C. Reached its maximum compressive strength
• D. Completed all hydration reactions

Explanation: Final setting marks the stage when the paste has lost plasticity and become sufficiently rigid.

• A. Release water and increase workability
• B. Absorb water and reduce workability
• C. Prevent cement hydration completely
• D. Increase the cement content automatically

Explanation: Dry porous aggregate absorbs part of the mixing water during mixing. The remaining free water decreases, so the concrete may become less…

• A. Cause immediate flash set
• B. Increase aggregate absorption
• C. Delay setting of concrete
• D. Remove entrained air completely

Explanation: Retarding admixtures extend the setting time, which is useful in hot weather or during long transport.

• A. 20 MPa
• B. 25 MPa
• C. 30 MPa
• D. 35 MPa

Explanation: In the usual grade notation, the number following M represents the characteristic compressive strength at 28 days in MPa.

• A. Lowers the pore-water alkalinity
• B. Raises the pore-water alkalinity
• C. Increases the cement content
• D. Prevents oxygen from reaching steel

Explanation: Carbonation reacts with alkaline cement products and lowers the pH of the concrete.

• A. Internal water-cement ratio
• B. Surface hardness and uniformity
• C. Aggregate absorption capacity
• D. Initial setting time

Explanation: A rebound hammer measures the rebound of a spring-driven mass and mainly indicates surface hardness and relative uniformity.

• A. Aggregate surface texture
• B. Aggregate water absorption
• C. Aggregate abrasion resistance
• D. Aggregate particle shape

Explanation: Abrasion resistance shows how well aggregate withstands rubbing and traffic wear.

• A. Untreated sewage water
• B. Highly saline seawater
• C. Acidic industrial water
• D. Potable drinking water

Explanation: Potable water is generally suitable because it normally contains no harmful concentrations of substances that interfere with cement…

• A. Tricalcium aluminate
• B. Dicalcium silicate
• C. Tricalcium silicate
• D. Tetracalcium aluminoferrite

Explanation: Tricalcium aluminate, commonly written as C3A, reacts rapidly with water and contributes substantially to heat generation.

• A. Increased by the aggregate surface moisture
• B. Reduced by the aggregate surface moisture
• C. Kept unchanged in every case
• D. Replaced by additional cement

Explanation: Wet aggregates contribute water to the mix, so the added batch water should be reduced to maintain the intended water-cement ratio.

• A. Delay cement hydration
• B. Increase the cement content
• C. Remove entrapped air voids
• D. Reduce aggregate size

Explanation: Compaction expels entrapped air and brings the concrete into close contact with reinforcement and formwork.

• A. Resistance to crushing
• B. Cement content
• C. Water absorption limit
• D. Average particle size

Explanation: Fineness modulus is an index of the average coarseness or fineness of an aggregate based on sieve analysis.

• A. Creep
• B. Elastic rebound
• C. Bleeding
• D. Segregation

Explanation: Creep is the time-dependent deformation that develops under sustained stress.

• A. Complete elimination of curing
• B. Normal production variation
• C. Reduction of aggregate volume
• D. Increase in setting time

Explanation: The target mean strength exceeds the specified characteristic strength so that normal variations in materials, batching and workmanship do…

• A. Open-air exposure
• B. Dry-air curing
• C. Membrane curing
• D. Repeated heating

Explanation: Membrane curing seals the concrete surface and reduces moisture loss when ponding or continuous sprinkling is impractical.

• A. Curling
• B. Scaling
• C. Crazing
• D. Dusting

Explanation: Dusting is the formation of a weak, powdery surface layer that can result from excess water, poor finishing or inadequate curing.