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Questions and Answers
What is the main purpose of the fineness test of cement?
What is the main purpose of the fineness test of cement?
Which method is NOT used to test the fineness of cement?
Which method is NOT used to test the fineness of cement?
During the normal consistency test, how deep should the Vicat plunger penetrate into the cement paste?
During the normal consistency test, how deep should the Vicat plunger penetrate into the cement paste?
How much water is added to 400 grams of cement during the normal consistency test?
How much water is added to 400 grams of cement during the normal consistency test?
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What is the maximum allowable residue on the sieve for ordinary cement in the fineness test?
What is the maximum allowable residue on the sieve for ordinary cement in the fineness test?
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What is the purpose of determining the initial setting time of cement?
What is the purpose of determining the initial setting time of cement?
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How is the percentage of water required for normal consistency calculated?
How is the percentage of water required for normal consistency calculated?
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What measurement device is used to test the initial and final setting times of cement?
What measurement device is used to test the initial and final setting times of cement?
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What is the significance of the soundness test for cement?
What is the significance of the soundness test for cement?
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When conducting a compressive strength test with standard sand, how is the water measured?
When conducting a compressive strength test with standard sand, how is the water measured?
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Study Notes
Laboratory Tests of Cement
- Key physical tests for cement include:
- Fineness Test
- Normal Consistency Test
- Initial and Final Setting Time Test
- Soundness Test
- Compressive Strength Test
Fineness Test of Cement
- Determines the degree of grinding of cement.
- Conducted through:
-
Sieving:
- Weigh 100 grams of cement on standard IS sieve no 9 (90 microns).
- Break air-set lumps, sieve for 15 minutes.
- Residue on sieve must not exceed:
- 10% for ordinary cement
- 5% for rapid hardening or low heat cement
- Specific Surface: Measurement method not detailed but focuses on surface area.
-
Sieving:
Normal Consistency Test
- Evaluates water quantity needed for standard cement paste consistency.
- Uses Vicat apparatus for testing:
- A 10 mm diameter, 40-50 mm long Vicat plunger penetrates the paste.
- Proper consistency allows penetration of 5-7 mm from the bottom.
- Procedure involves:
- Mixing 400 gm of sieved cement with water.
- Adjusting water until desired penetration is achieved.
- Calculation of water percentage for normal consistency: P = (W1 / W) × 100.
Initial and Final Setting Time Test
- Measures duration for cement paste to become solid after water mixing.
- Divided into two stages:
- Initial Setting Time: Moment cement loses plasticity.
- Final Setting Time: Duration until cement mass becomes hard.
- Testing with Vicat apparatus:
- About 400 gm of sieved cement is mixed with water at 0.85 P (where P is water percentage for normal consistency).
- Timing starts at water addition; use needle for penetration measurement.
- Record time until needle can no longer penetrate 5 mm into paste.
Soundness Test
- Assesses for excess free lime and magnesia in cement.
- Conducted using Le-Chatelier apparatus.
Compressive Strength Test
- Evaluates the strength of cement:
- Mix 200 gm of cement with 600 gm of standard sand.
- Water added based on consistency percentage (P/4 + 3% for standard sand; P/4 + 3.5% for ordinary sand).
- Mixture forms uniform paste for strength measurement.
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Description
This quiz covers the essential laboratory tests conducted on cement, including fineness, normal consistency, setting times, soundness, and compressive strength. Learn about the significance of these tests and the methods used to assess the properties of cement. Enhance your practical understanding of cement testing through this engaging quiz.
