11. The compressive strength of cement is typically tested after:
a) 1 day
b) 7 days
c) 28 days
d) 90 days
View Answer
Correct answer: c) 28 days
Explanation: The compressive strength of cement is commonly tested after 28 days of curing to assess its quality and performance. This time period allows for sufficient hydration and strength development.
12. Rapid hardening cement is characterized by:
a) High early strength
b) Low water requirement
c) High durability
d) Low heat of hydration
View Answer
Correct answer: a) High early strength
Explanation: Rapid hardening cement is known for its ability to develop high early strength, making it suitable for applications where quick setting and early strength gain are required.
13. Which of the following is an advantage of using cement in construction?
a) Low cost
b) Environmental friendliness
c) Resistance to fire
d) Lightweight
View Answer
Correct answer: c) Resistance to fire
Explanation: Cement offers excellent fire resistance properties, making it a preferred choice for building structures that require fire protection.
14. The term “workability” in relation to cement refers to its:
a) Resistance to compressive forces
b) Ability to flow and be easily molded
c) Durability over time
d) Chemical stability
View Answer
Correct answer: b) Ability to flow and be easily molded
Explanation: Workability refers to the ease with which cement paste can be mixed, placed, and molded. It is influenced by factors such as water-cement ratio, fineness, and admixtures.
15. The process of adding water to cement to form a paste is called:
a) Mixing
b) Curing
c) Hydration
d) Slaking
View Answer
Correct answer: a) Mixing
Explanation: Mixing involves the addition of water to cement to create a paste with the desired consistency for application in construction.
16. The term “curing” in cement refers to the process of:
a) Mixing cement with aggregates
b) Applying a protective coating to the surface
c) Allowing the cement to dry
d) Providing a favorable environment for hydration and strength development
View Answer
Correct answer: d) Providing a favorable environment for hydration and strength development
Explanation: Curing is the process of maintaining adequate moisture and temperature conditions for cement to undergo proper hydration and develop the desired strength.
17. The term “setting time” in cement refers to the time taken for the cement paste to:
a) Harden and gain strength
b) Dry and shrink
c) Expand and crack
d) Dissolve in water
View Answer
Correct answer: a) Harden and gain strength
Explanation: Setting time is the time duration after mixing when the cement paste undergoes a transition from a plastic state to a hardened state, gaining strength over timeand becoming rigid.
18. The term “hydration” in cement refers to the chemical reaction between cement and:
a) Water
b) Air
c) Aggregates
d) Admixtures
View Answer
Correct answer: a) Water
Explanation: Hydration is the chemical reaction between cement and water, resulting in the formation of calcium silicate hydrate and other compounds that contribute to the hardening and strength development of the cement paste.
19. The term “soundness” in cement refers to its ability to:
a) Resist chemical attack
b) Resist shrinkage
c) Retain its volume without significant expansion or contraction
d) Achieve high compressive strength
View Answer
Correct answer: c) Retain its volume without significant expansion or contraction
Explanation: Soundness refers to the ability of cement to retain its volume without undergoing significant expansion or contraction upon hydration. It is important to ensure the stability and durability of concrete structures.
20. The term “hydration products” in cement refers to the compounds formed as a result of:
a) Mixing cement with water
b) Adding aggregates to cement
c) Exposing cement to air
d) Applying a protective coating to the surface
View Answer
Correct answer: a) Mixing cement with water
Explanation: Hydration products are the chemical compounds formed when cement reacts with water during the hydration process. These compounds contribute to the strength and durability of the cement paste.
