Cement Testing MCQ with answer and solution

Concept

Standard consistency of cement is measured using the Vicat apparatus with a square needle or plunger attachment.

Step-by-step solution

1. Prepare a paste of cement with a weighed quantity of water (initially expressed as a percentage of weight of cement, e.g., 30%). 2. Fill the Vicat mould resting on a non-porous plate with the cement paste. 3. Smooth the surface of the paste and place the mould under the Vicat apparatus carrying the standard plunger (10 mm diameter). 4. Release the plunger gently to sink into the paste and note the reading on the indicator scale. 5. Repeat the test with varying percentages of water until the plunger penetrates to a depth of 5 to 7 mm from the bottom of the mould.

Explanation

The Vicat apparatus is standardly used in civil engineering laboratories to determine the standard consistency of cement paste, as specified by IS 4031 (Part 4). Standard consistency is defined as the water content that permits the Vicat plunger to penetrate to a point 5 to 7 mm from the bottom of the Vicat mould.

Why the other options are wrong

B: Le Chatelier apparatus is used for determining the soundness of cement. C: Blaine apparatus is used to determine the specific surface area (fineness) of cement. D: Universal Testing Machine (UTM) is used for testing the tensile and compressive strength of materials.

Shortcut

Remember: Vicat = Consistency and Setting time; Le Chatelier = Soundness; Blaine = Fineness.

Common mistake

Confusing the Vicat apparatus plunger for consistency with the Vicat needles used for initial and final setting time tests.