cement Flashcards
What is cement?
A binder that sets, hardens, and binds materials.
What are the two main types of cement?
- Hydraulic
- Non-hydraulic
How does non-hydraulic cement set?
It sets as it dries and reacts with carbon dioxide in the air.
What is hydraulic cement made from?
Activated aluminum silicates and pozzolanas like fly ash.
Which type of cement allows setting in wet conditions?
Hydraulic cement.
What are some applications of cement?
- Building homes
- Roads
- Bridges
- Dams
- Skyscrapers
What binding materials were used in ancient times?
- Mud
- Clay
- Lime
What did the Romans develop in the cement industry?
Hydraulic cement by mixing volcanic ash with lime.
When was Portland cement patented?
1824 by Joseph Aspdin.
What invention increased cement production efficiency in the 1850s?
Rotary kilns.
What are the physical properties of cement?
- Fineness
- Soundness
- Consistency
- Bulk Density
- Compressive Strength
- Flexural Strength
- Setting Time
- Heat of Hydration
- Specific Gravity
What does fineness refer to in cement?
The size of the particles of the cement.
What is soundness in cement?
Resistance to volume change after setting.
What is the bulk density range of cement?
62-78 lb/ft3.
What is compressive strength?
The load a cement cube can handle without failing.
What is the initial setting time?
Time from when water is added to cement until it starts losing plasticity.
What is the heat of hydration?
Heat generated when water is added to cement.
What is the specific gravity of Portland cement?
~3.15.
What does C₃A stand for?
Tricalcium Aluminate.
What is the effect of low C₃A in cement?
Increased sulphate resistance.
What role does C₃S play in cement?
Provides early strength.
What is the maximum allowed content of MgO in cement?
6%.
Which material is the main source of calcium oxide in cement?
Limestone (CaCO3).
What is the purpose of gypsum in cement?
Acts as a setting time regulator.
