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Created: 2024/07/06 13:42

Experiment no. 07

Experiment name: Determination of normal consistency of cement

Objective

The objective of this experiment is to,

1. Measure the normal consistency of Mir Portland Composite Cement.

Significance

Determining the normal consistency of cement is crucial as it affects the cement's workability and setting time. The normal consistency is used as a reference for preparing cement pastes for other tests, such as initial and final setting times. It ensures that the cement paste has the right fluidity, neither too stiff nor too runny, for proper hydration and strength development.

Apparatus

1. Beaker
2. Balance
3. Glass plate
4. Stopwatch
5. Thermometer
6. Hydrometer
7. Mixing pot
8. Trowel
9. Mask and hand gloves
10. Vicat apparatus with plunger
11. Sample: PCC Mir Brand

Data sheet

Calculation

Determination of water weight

For amount of cement = $650\text{[PARSE ERROR: Undefined("Command("space")")]}gm$, when percentage of,

1. Water is $26\mathrm{\%}$, amount of water = $650\times 0.26=169\text{[PARSE ERROR: Undefined("Command("space")")]}gm$
2. Water is $28\mathrm{\%}$, amount of water = $650\times 0.28=182\text{[PARSE ERROR: Undefined("Command("space")")]}gm$
3. Water is $30\mathrm{\%}$, amount of water = $650\times 0.30=195\text{[PARSE ERROR: Undefined("Command("space")")]}gm$
4. Water is $32\mathrm{\%}$, amount of water = $650\times 0.32=208\text{[PARSE ERROR: Undefined("Command("space")")]}gm$

Graph

Result

The normal consistency of the Mir PCC was determined to be 28.2% from graph.

Discussion

The experiment successfully determined the normal consistency of Mir Portland Composite Cement to be 28.2% through penetration using the Vicat apparatus. This is the water percentage at which the penetration depth of the Vicat plunger is about 10 mm. This value indicates the amount of water required to achieve a workable cement paste suitable for further testing and practical applications.

At lower water percentages (26%), the paste was too stiff, resulting in minimal penetration (1.5 mm). As the water content increased to 28% and 30%, the penetration increased significantly (9 mm and 24 mm, respectively), indicating better workability. At 32% water, the penetration was too high (40 mm), suggesting the paste was overly fluid.

Knowing the normal consistency, we can use it as a guideline for preparing cement paste for the next tests as well as other construction activities.