Laboratory Test of Cement

Questions and Answers

What is the main purpose of the fineness test of cement?

To check the proper grinding of cement (correct)

To assess the soundness of the cement

To evaluate the setting times

To determine the compressive strength

Which method is NOT used to test the fineness of cement?

By determining the compressive strength (correct)

By weighing the residue on the sieve

By determining the specific surface

By sieving

During the normal consistency test, how deep should the Vicat plunger penetrate into the cement paste?

3 to 5 mm from the bottom

1 to 3 mm from the bottom

5 to 7 mm from the bottom (correct)

7 to 10 mm from the bottom

How much water is added to 400 grams of cement during the normal consistency test?

100 grams Signup and view all the answers

What is the maximum allowable residue on the sieve for ordinary cement in the fineness test?

10% Signup and view all the answers

What is the purpose of determining the initial setting time of cement?

To find the moment when the cement paste loses its plasticity Signup and view all the answers

How is the percentage of water required for normal consistency calculated?

P = (W1 / W) × 100 Signup and view all the answers

What measurement device is used to test the initial and final setting times of cement?

Vicat apparatus Signup and view all the answers

What is the significance of the soundness test for cement?

To determine the presence of excess free lime and magnesia Signup and view all the answers

When conducting a compressive strength test with standard sand, how is the water measured?

At P/4 + 3% for standard sand and P/4 + 3.5% for ordinary sand Signup and view all the answers

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.

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.

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.