Concrete Technology Questions and Answers – Hydration of Cement

This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Hydration of Cement”.

1. What is hydration of cement?
a) Chemical reaction of cement with acid
b) Chemical reaction of cement with water
c) Chemical reaction of cement with base
d) Chemical reaction of cement with salt, and acid
View Answer

Answer: b
Explanation: As water comes into contact with cement particles, hydration reactions immediately starts at the surface of the particles.

2. As the hydration proceeds the deposits of hydrated products on the original cement grains makes the diffusion of water to unhydrated nucleus ________
a) Easy
b) Very difficult
c) Very easy
d) Average
View Answer

Answer: b
Explanation: It is difficult thus the rate of hydration decreases with time & as result hydration may take several years.

3. The development of first 28 days strength is on account of the hydration of __________
a) C2S
b) C3S
c) C3A
d) C4AF
View Answer

Answer: b
Explanation: Higher C3S→higher early strength-higher heat generation (roads, cold environments). Higher CS→lower early strength-lower heat generation (dams).
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4. Which compound is liberates higher heat?
a) C2S
b) C3S
c) C3A
d) C4AF
View Answer

Answer: b
Explanation: C3S having a faster rate of reaction accompanied by greater heat generation developes early strength of the paste.

5. Which compound is liberates lower heat?
a) C2S
b) C3S
c) C3A
d) C4AF
View Answer

Answer: a
Explanation: C2S hydrates & hardens slowly so results in less heat generation & developes most of the ultimate strength.
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6. Which compound may lead to a rapid stiffening of the paste with a large amount of the heat generation?
a) C2S
b) C3S
c) C3A
d) C4AF
View Answer

Answer: c
Explanation: C3A is characteristically fast reacting with water & may lead to a rapid stiffening of the paste with a large amount of the heat generation (Flash-Set)-(Quick-Set).

7. In order to prevent this rapid reaction _______ is added to the clinker.
a) C4AF
b) Gypsum
c) Water
d) Extra cement
View Answer

Answer: b
Explanation: In order to prevent this rapid reaction gypsum is added to the clinker. Gypsum, C3A&water react to form relatively insoluble Calcium-Sulfo-Aluminates.
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Sanfoundry Global Education & Learning Series – Concrete Technology.

To practice all areas of Concrete Technology, here is complete set of 1000+ Multiple Choice Questions and Answers.

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If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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