cement tests

Practical Steps – Start to End

1. Preparation:

Clean all equipment (Vicat apparatus, mold, glass plate).

Maintain lab temperature at 27 ± 2°C.

Use freshly opened cement (avoid lumps or moisture).

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2. Initial Weighing:

Take 400 grams of cement.

Start with 25% water (i.e., 100 ml water).

Mix water and cement quickly and uniformly for 3–5 minutes.

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3. Molding the Paste:

Place the Vicat mold on the glass plate.

Fill it with the cement paste without vibration.

Level the surface with a trowel.

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4. Testing Penetration:

Lower the plunger (10 mm diameter) to just touch the top of the paste.

Release it and observe how far it penetrates.

If it penetrates to 5–7 mm from the bottom, that water content is the standard consistency.

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5. Repeat with Adjusted Water (if needed):

If penetration is too deep or shallow:

Change water content (±1–2%)

Remake the paste

Repeat penetration test until result is within 5–7 mm from bottom.

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Example Table of Results:

Therefore, standard consistency = 28%

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Summary Table:

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Purpose in Practice:

The determined consistency (P%) is essential for other tests:

Setting Time Test: use 0.85 × P

Soundness Test

Compressive Strength of Mortar Cubes

1. Setting Time Test of Cement

IS Code: IS 4031 (Part 5)

Purpose:

To determine:

Initial setting time – when the paste begins to harden.

Final setting time – when the paste fully hardens.

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Apparatus:

Vicat Apparatus

Initial setting: Needle (1.13 mm diameter)

Final setting: Needle with annular attachment

Stop watch

Vicat mold

Glass plate

Weighing balance

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Procedure:

1. Paste Preparation:

Take 400 g cement and mix with water = 0.85 × P (P = % from standard consistency test).

Mix for 3–5 minutes.

2. Filling the Mold:

Fill Vicat mold with cement paste and level the surface.

3. Initial Setting Time:

Start stopwatch at the time of water addition.

Lower the initial setting needle gently to touch the paste.

Release it and check penetration.

Repeat every 10 min.

The time when needle penetrates only up to 5–7 mm from bottom is initial setting time.

4. Final Setting Time:

Change to final setting needle with ring.

Continue test every 10–15 min.

Final setting is when the needle no longer leaves an impression on the paste surface.

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IS Requirements for OPC:

Initial Setting Time: ≥ 30 minutes

Final Setting Time: ≤ 600 minutes (10 hours)

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Example Table:

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2. Soundness Test of Cement

IS Code: IS 4031 (Part 3)

Purpose:

To check volumetric stability of cement (i.e., ensure no excessive expansion after setting).

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Test Methods:

Le Chatelier Method (for OPC, PPC)

Autoclave Method (for high alumina cement)

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A. Le Chatelier Test

Apparatus:

Le Chatelier mold (split brass ring with two indicators)

Glass plate

Measuring scale

Water bath

Procedure:

1. Paste Preparation:

Use 0.78 × P water with 200 g cement.

2. Filling the Mold:

Place mold on glass plate.

Fill with paste and cover with another plate.

Slightly weight it.

3. Initial Measurement:

Measure and record distance between indicator points (A1).

4. Steam Curing:

Keep mold in water at 27°C for 24 hours.

5. Boiling:

Then boil water for 3 hours.

Cool down and take final reading (A2).

6. Soundness = A2 – A1 (in mm)

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IS Requirement:

Expansion should not exceed 10 mm

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Example Table: