Virtual Labs

Heat of hydration of cement

What is the primary reason for determining the heat of hydration of cement?

a: To measure the setting time of cement Explanation

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b: To prevent thermal cracking in concrete Explanation

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c: To determine the fineness of cement Explanation

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d: To improve the workability of cement Explanation

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Which chemical reaction occurs when water is added to cement?

a: Oxidation Explanation

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b: Hydration Explanation

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c: Reduction Explanation

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d: Evaporation Explanation

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What type of reaction is the hydration of cement?

a: Endothermic Explanation

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b: Exothermic Explanation

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c: Neutral Explanation

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d: Reversible Explanation

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Why is gypsum added to cement?

a: To increase strength Explanation

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b: To accelerate the setting time Explanation

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c: To control the rapid heat and reaction of C₃A Explanation

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d: To improve fineness Explanation

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Which apparatus is used to determine the heat of hydration of cement?

a: Vicat’s apparatus Explanation

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b: Le Chatelier’s apparatus Explanation

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c: Potentiometer Explanation

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d: Calorimeter Explanation

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How does the fineness of cement affect the heat of hydration?

a: Increases heat of hydration Explanation

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b: Decreases heat of hydration Explanation

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c: Has no effect on hydration Explanation

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d: Only affects setting time Explanation

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What is the role of tricalcium silicate (C₃S) in hydration?

a: Strength development in the first 28 days Explanation

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b: Reducing shrinkage Explanation

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c: Delaying hydration reaction Explanation

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d: Providing sulfate resistance Explanation

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Which compound in cement is responsible for releasing the maximum heat during hydration?

a: C₂S Explanation

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b: C₃S Explanation

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c: C₃A Explanation

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d: C₄AF Explanation

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How does increasing the water-cement ratio affect the heat of hydration?

a: Increases heat generation Explanation

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b: Decreases heat generation Explanation

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c: No effect on hydration Explanation

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d: Cement does not hydrate in excess water Explanation

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What is the ideal temperature for conducting a heat of hydration test?

a: 15 ± 2°C Explanation

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b: 27 ± 2°C Explanation

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c: 35 ± 2°C Explanation

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d: 50 ± 2°C Explanation

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How does an increase in curing temperature affect the heat of hydration?

a: Reduces heat generation Explanation

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b: Increases heat generation Explanation

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c: No effect on hydration Explanation

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d: Slows down hydration Explanation

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Why is the heat of hydration lower in low-heat cement?

a: It contains more C₃S Explanation

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b: It contains more C₂S Explanation

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c: It has higher C₃A content Explanation

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d: It reacts faster Explanation

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Which hydration product is mainly responsible for strength development in concrete?

a: Calcium hydroxide Explanation

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b: Tobermorite gel (C-S-H gel) Explanation

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c: Calcium chloride Explanation

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d: Aluminium hydroxide Explanation

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How does the composition of cement influence its heat of hydration?

a: More C₃S and C₃A increase the heat of hydration Explanation

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b: More C₂S and C₄AF increase the heat of hydration Explanation

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c: More gypsum leads to higher heat generation Explanation

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d: More water increases heat generation Explanation

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Why is the heat of hydration significant in mass concrete structures?

a: It helps in increasing setting time Explanation

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b: It prevents early-age cracking due to excessive heat Explanation

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c: It improves workability Explanation

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d: It allows for faster strength gain Explanation

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