Properties and Testing of Construction Materials (Concrete, Steel, Asphalt)
1. What is the standard curing period for concrete to reach its designed compressive strength?
A. 7 days
B. 14 days
C. 28 days
D. 56 days
Answer: C
Explanation: The standard curing period for concrete to reach its full designed compressive strength is 28 days.
2. What is the minimum compressive strength of Class A concrete used in water-retaining structures?
A. 2,500 psi
B. 3,000 psi
C. 3,500 psi
D. 4,000 psi
Answer: B
Explanation: Class A concrete typically has a minimum compressive strength of 3,000 psi (20.7 MPa) and is commonly used in sanitary structures.
A. 2,500 psi
B. 3,000 psi
C. 3,500 psi
D. 4,000 psi
Answer: B
Explanation: Class A concrete typically has a minimum compressive strength of 3,000 psi (20.7 MPa) and is commonly used in sanitary structures.
3. Which test determines the workability of fresh concrete?
A. Compressive strength test
B. Abrasion test
C. Tensile strength test
D. Slump test
Answer: D
Explanation: The slump test measures the consistency and workability of fresh concrete.
4. What is the most commonly used type of cement for general construction?
A. Type I – Ordinary Portland Cement
B. Type II – Moderate Sulfate Resistance
C. Type III – High Early Strength
D. Type V – High Sulfate Resistance
Answer: A
Explanation: Type I OPC (Ordinary Portland Cement) is the most widely used for general construction.
5. The water-cement ratio primarily affects which property of concrete?
A. Strength
B. Workability
C. Durability
D. All of the above
Answer: D
Explanation: The water-cement ratio affects strength, workability, and durability of concrete. A higher ratio leads to lower strength but higher workability.
6. Which of the following materials improves the tensile strength of concrete?
A. Aggregates
B. Cement
C. Steel reinforcement
D. Water
Answer: C
Explanation: Concrete is weak in tension, so steel reinforcement is added to improve tensile strength.
7. Which test is used to measure the bonding strength between aggregates and bitumen in asphalt?
A. Ductility test
B. Marshall stability test
C. Stripping test
D. Penetration test
Answer: C
Explanation: The stripping test determines how well aggregates bond with bitumen and resist moisture damage.
8. Which of the following tests is used to determine the softening point of bitumen?
A. Penetration test
B. Ring and Ball test
C. Ductility test
D. Flashpoint test
Answer: B
Explanation: The Ring and Ball test determines the temperature at which bitumen softens.
9. Steel used in reinforced concrete must have what characteristic?
A. High yield strength
B. High ductility
C. Good bond with concrete
D. All of the above
Answer: D
Explanation: Reinforcing steel should have high yield strength, ductility, and good bonding properties with concrete.
10. The air-entrainment in concrete improves:
A. Strength
B. Workability
C. Resistance to freeze-thaw cycles
D. Elasticity
Answer: C
Explanation: Air-entrained concrete increases durability by resisting freeze-thaw cycles.
Construction Methods and Techniques for Infrastructure Projects
11. The most common method of placing concrete in high-rise structures is:
A. Pumping
B. Buckets
C. Chutes
D. Manual pouring
Answer: A
Explanation: Pumping is used for placing concrete in high-rise structures because it is fast and efficient.
12. In formwork design, what is the primary function of ties and braces?
A. Increase concrete strength
B. Reduce curing time
C. Improve workability
D. Prevent collapse of the formwork
Answer: D
Explanation: Ties and braces help stabilize formwork and prevent failure during concrete pouring.
13. The best method to prevent cold joints in concrete is:
A. Use of superplasticizers
B. Continuous pouring
C. Adding more cement
D. Reducing water content
Answer: B
Explanation: Cold joints occur when concrete sets before new concrete is poured. Continuous pouring prevents this issue.
14. Which of the following methods is commonly used to compact asphalt pavements?
A. Vibratory roller
B. Hand compactor
C. Water curing
D. Chiseling
Answer: A
Explanation: A vibratory roller is used for compacting asphalt pavements to increase density and strength.
15. The primary purpose of a waterstop in concrete joints is to:
A. Provide additional strength
B. Prevent water leakage
C. Improve workability
D. Reduce drying shrinkage
Answer: B
Explanation: Waterstops are used in expansion joints to prevent water leakage in structures like water tanks and sewage treatment plants.
Quality Control and Assurance in Construction
16. The most critical factor affecting the durability of concrete is:
A. Water-cement ratio
B. Aggregate size
C. Temperature
D. Mixing method
Answer: A
Explanation: The lower the water-cement ratio, the more durable the concrete.
17. What is the primary goal of quality assurance in construction?
A. Identify defective materials
B. Reduce worker safety measures
C. Increase project cost
D. Ensure compliance with specifications
Answer: D
Explanation: Quality assurance ensures construction meets design specifications.
18. Which test determines the strength of hardened concrete?
A. Slump test
B. Compression test
C. Penetration test
D. Marshall test
Answer: B
Explanation: The compression test measures the strength of hardened concrete.
19. The main cause of honeycombing in concrete structures is:
A. Low water content
B. Slow curing
C. Overuse of cement
D. Poor compaction
Answer: D
Explanation: Poor compaction creates voids in concrete, leading to honeycombing.
20. The most effective method to ensure uniform concrete mix is:
A. Hand mixing
B. Manual pouring
C. Spraying
D. Mechanical mixing
Answer: D
Explanation: Mechanical mixing ensures uniform concrete consistency.
21. What is the standard test specimen size for a concrete compressive strength test?
A. 100 mm x 200 mm cylinder
B. 150 mm x 300 mm cylinder
C. 200 mm x 400 mm cylinder
D. 50 mm x 100 mm cube
Answer: B
Explanation: The standard specimen size for compressive strength testing in concrete is 150 mm x 300 mm (6 inches x 12 inches).
22. The primary objective of a slump test in fresh concrete is to measure its:
A. Compressive strength
B. Water content
C. Workability
D. Durability
Answer: C
Explanation: The slump test determines the workability or flowability of fresh concrete before placing.
23. Which construction material has the highest thermal expansion coefficient?
A. Concrete
B. Steel
C. Wood
D. Brick
Answer: B
Explanation: Steel expands more than concrete due to temperature changes, which is why expansion joints are necessary.
24. In asphalt pavement construction, what is the purpose of a prime coat?
A. Improve surface texture
B. Increase bonding between layers
C. Reduce water absorption
D. Enhance skid resistance
Answer: B
Explanation: A prime coat improves bonding between the asphalt layer and the base course.
25. What is the main cause of bleeding in fresh concrete?
A. Excessive water content
B. High cement content
C. Poor compaction
D. Low aggregate size
Answer: A
Explanation: Bleeding occurs when excess water rises to the surface due to high water-cement ratio.
26. What type of concrete curing method is commonly used for large-scale slabs?
A. Ponding
B. Steam curing
C. Membrane curing
D. Water sprinkling
Answer: A
Explanation: Ponding ensures continuous water supply and prevents cracking in large slabs.
27. Which of the following causes segregation in concrete during placement?
A. Using air-entraining agents
B. Proper mixing
C. Excessive vibration
D. Low water-cement ratio
Answer: C
Explanation: Over-vibration separates aggregates and cement paste, leading to segregation.
28. Which test is used to determine the abrasion resistance of aggregates?
A. Los Angeles Abrasion Test
B. Marshall Stability Test
C. Vebe Test
D. Schmidt Hammer Test
Answer: A
Explanation: The Los Angeles Abrasion Test measures the durability and hardness of aggregates under wear.
29. What is the minimum curing period for concrete structures exposed to hot weather conditions?
A. 3 days
B. 7 days
C. 14 days
D. 28 days
Answer: C
Explanation: In hot weather, a minimum of 14 days curing is recommended to prevent rapid moisture loss.
30. What is the common method for testing the strength of hardened concrete in existing structures without damaging it?
A. Core testing
B. Schmidt Hammer Test
C. Compression testing
D. Flexural strength test
Answer: B
Explanation: The Schmidt Hammer Test is a non-destructive test used to estimate concrete strength without damaging the structure.