cement Flashcards
(45 cards)
What is the primary ingredient used in cement production?
Powdered stone, clay, and other materials
The burning of these materials results in cement.
Who invented Portland cement?
Joseph Aspdin in 1824
Aspdin was an English inventor who significantly contributed to the cement industry.
What are the main components of concrete?
- Cement
- Sand
- Aggregate
- Water
These components are mixed to create concrete.
What is the significance of excess lime in cement?
It decreases the strength of cement and causes it to set quickly.
A balance of lime is crucial for optimal cement properties.
True or False: Excess silica increases the strength of cement but prolongs the setting time.
True
The presence of excess silica is beneficial for the strength of cement.
What effect does excessive alumina have on cement?
It weakens the cement.
Alumina is necessary in controlled amounts for proper cement strength.
What is the first cement factory established in India?
Travancore Cement Limited
This factory was crucial in the development of cement production in India.
What is heat of hydration?
Heat released during the chemical reaction after mixing water with cement.
This process is also known as an exothermic reaction.
Fill in the blank: The main component responsible for initial strength in cement is _______.
Tricalcium silicate
This compound is crucial for the early strength development of cement.
What is the role of gypsum in cement?
It controls the setting time of cement.
Gypsum is added to regulate how quickly the cement sets.
Fill in the blank: The presence of excess magnesia in cement makes it _______.
Unsound
Excessive magnesia can lead to structural issues in cement.
What are the two main processes of cement manufacturing?
- Dry process
- Wet process
The choice of process affects the efficiency and quality of cement production.
What is the significance of the lime saturation factor?
It indicates the balance of lime to silica, alumina, and iron oxide in cement.
A proper lime saturation factor is essential for achieving desired cement quality.
What is the compressive strength range of cement used for general construction?
Between 33 N/mm² and 43 N/mm²
This strength range is typical for normal environmental conditions.
What is the function of tricalcium aluminate in cement?
It contributes to early strength development and influences setting time.
This component is critical for the initial phases of cement hardening.
What is the maximum allowable percentage of insoluble residue in cement?
Should not be greater than 1%
Higher insoluble residues may indicate poor quality cement.
Fill in the blank: The chemical reaction that occurs within 24 hours of mixing water with cement is responsible for _______.
Initial and final setting time
This reaction is critical for the hardening process of cement.
What is the role of iron oxide in cement?
It provides color and contributes to the strength of cement.
Iron oxide is essential for achieving the desired properties of cement.
True or False: High alumina cement is resistant to freezing and thawing.
True
High alumina cement is known for its durability in extreme conditions.
What is a potential consequence of storing cement in jute bags for more than three months?
Moisture absorption leading to degradation
Cement should be stored in airtight containers to maintain quality.
What is the primary use of rapid hardening cement?
For projects requiring quick setting and early strength gain
This type of cement is particularly useful in urgent construction scenarios.
What is the significance of the percentage of alumina to iron oxide in cement?
It should not be less than 0.66 and not greater than 1.02
This ratio influences the quality and performance of the cement.
What does the term ‘exothermic process’ refer to in cement?
Heat of hydration
This process is critical for the curing and strength development of cement.
What is Blast Furnace cement used for?
Plastering and masonry works
Blast Furnace cement is a waste product obtained from the manufacturing process of pig iron.
