Cement Flashcards
(25 cards)
What is the primary role of excess lime in cement?
Gives colour, hardness, and strength to cement
Excess lime is a key ingredient in the composition of cement, enhancing its properties.
What is the order of heat of hydration for the compounds in cement?
C3A > C3S > C4AF > C2S
What percentage of final strength does ordinary cement achieve in 28 days?
70%
What percentage of final strength does ordinary cement achieve in one year?
90%
What are argillaceous materials?
Materials containing clay, primarily used in cement production.
What is the typical percentage of C3S in ordinary Portland cement?
C3S > C2S > C3A > C4AF
Fill in the blank: The heat of hydration of tricalcium aluminate is ______.
3.8 J/g
Fill in the blank: The specific surface area for OPC is ______.
2250 m²/g
What is the initial setting time for ordinary Portland cement?
Not less than 30 minutes
What is the final setting time for high alumina cement?
Not more than 10 hours
What is the minimum compressive strength for cement after 3 days?
Should not be less than 115 kg/cm²
What is the minimum tensile strength for cement after 7 days?
Should not be less than 25 kg/cm²
Fill in the blank: The percentage of C4AF in cement is typically ______.
5-11%
Fill in the blank: The percentage of C2S in cement is typically ______.
25-50%
True or False: Rapid hardening cement has a specific surface area of 3250 m²/g.
True
What is the characteristic color of chromium oxide?
Green
What is the characteristic color of cobalt?
Blue
What is the characteristic color of iron oxide?
Brown, red, yellow
What is the characteristic color of manganese oxide?
Black or brown
What is the significance of the specific surface area in cement?
It affects the reactivity and strength development of the cement.
Fill in the blank: Low heat cement has a lower percentage of C3A of about ______.
2%
Fill in the blank: Low heat cement has a higher percentage of C2S of about ______.
25-40%
What is the typical setting time for quick-setting cement?
5 minutes
