Mineral Compounds in Portland Cement

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What is the primary purpose of measuring the final setting time of cement?

To measure the gain in mechanical strength of the cement paste
To test the initial chemical reaction of cement with water
To determine the time required for the cement paste to completely lose its plasticity (correct)
To ensure the cement sets neither too rapidly nor too slowly

What is the difference between setting and hardening of cement?

Setting refers to the stiffening of the cement paste to a defined consistency, while hardening refers to the time required for this process
Setting refers to the initial chemical reaction of cement with water, while hardening refers to the gain in mechanical strength (correct)
Setting and hardening are the same process, just described using different terminology
Setting refers to the time required for the cement paste to lose its plasticity, while hardening refers to the time required for the cement to become rigid

Why is it important for cement to not set too rapidly or too slowly?

Rapid setting can lead to insufficient time for transportation and placement, while slow setting can delay the actual use of the structure (correct)
Rapid setting can lead to insufficient time for curing, while slow setting can delay the final hardening process
Rapid setting can lead to insufficient time for hydration, while slow setting can delay the gain in mechanical strength
Rapid setting can lead to insufficient time for compaction, while slow setting can delay the initial chemical reaction

What is the purpose of the initial setting time test for cement?

To ensure the cement sets at the desired rate for transportation and placement (A) Signup and view all the answers

What is the purpose of the final setting time test for cement?

To measure the time required for the cement paste to completely lose its plasticity (B) Signup and view all the answers

How is the final setting time of cement determined?

By measuring the time when a needle used for testing fails to make an impression on the surface of the test block (C) Signup and view all the answers

What is the relationship between setting time and the initial chemical reaction of cement with water?

Setting time is indirectly related to the initial chemical reaction of cement with water (B) Signup and view all the answers

What is the main purpose of delaying the initial setting time of cement?

To ensure sufficient time for transportation and placement of the concrete (B) Signup and view all the answers

How does setting time relate to the hardening of cement?

Setting time refers to the stiffening of the cement paste, while hardening refers to the gain in mechanical strength (D) Signup and view all the answers

What is the main difference between initial setting time and final setting time of cement?

Initial setting time is the time when the paste starts losing its plasticity, while final setting time is the time when the paste completely loses its plasticity (D) Signup and view all the answers