Standard test method for the determination of the normal consistency of hydraulic cement.
(ASTM C 187-04)
- To determine of the normal consistancy of hydraulic cement.
- To determine the amount of water required to prepare hydrualic cement pastes for testing.
- Vicat’s apparatus
- Plunger(dia = 10mm, length = 50mm)
- Weighing balance
- Glass plate and trowel
- Spatula and safety gloves
The thickness or viscosity of the cement paste is called consistency. It is the ratio of thickness of water to the mass of cement expressed as percentage.
Standard cement paste:
It is the cement paste for which the 10mm diameter plunger in a standard VICAT’S test penetrates to such an extent that its distance from the bottom is 10±1mm. the normal consistency of cement is 28%.
It is the thickness or viscosity of standard paste and is expressed as the percentage of weight of water.
- Air temperature 20 – 27.5 ͦ C
- Water temperature 23 ± 2 ͦ C
- Humidity should not be less than 50%.
- Take 650g of cement and mix it with 26% of water by weight of dry cement. The Gauging time should not be more than 4min ±15 sec.
- Fill the Vicat mould with paste and level it with trowel.
- Lower the plunger gently till it touches the cement surface.
- Release the plunger allowing it to sink into the paste.
- Note the reading on the gauge.
- Repeat the above procedure taking fresh samples of cement and different quantities of water until the reading on the gauge is 10±1mm.
- Gauging time should be strictly observed
- Room temp. Should be well maintained as per test requirement.
- All apparatus used should be clean.
- The experiment should be performed away from vibrations and other disturbances.
Observation and calculation:
Weight of cement= 650g
|Sr. No.||Weight of cement (g)||Percentage of water by weight of dry cement (g)||W/C||Vicat penetration (mm)|
- This experiment tells us the amount of water content at which we can obtain the maximum strength of cement.
- The achieved Standard Consistency is coming within the range of water (26% to 33%) So, the standard consistency of cement paste is 11mm
- The standard penetration is observed at 26% water by weight which is the between the range of ASTM
- This test also gives us information that how much amount of water is enough to prepare a paste of cement before using it at the site at the time of construction.