Determination of the density of hydraulic cement in relation to the design of Portland cement concrete mix
Tools and Materials
- Standard Le-Chatelier flask as shown below
- Heavy rubber pad approximately 12 inches × 12 inches square
- Lead ring weight to fit around the stem of the flask
- Portland cement
- Fill a mark on the stem between the 0 and 1 cm mark with kerosene in the flask. If there is any drop above the liquid level, dry the inside of the flask.
- Place the flask in a constant temperature bath and record the initial height of the kerosene in the flask. The constant temperature bath should be maintained at such a temperature that the temperature variation between the initial and final readings within the flask does not exceed 0.2 °C.
- Carefully introduce approximately 64 g of cement, weighing to the nearest 0.1 g. Try not to stick the cement to the inside of the flask or to the neck. Cement should be introduced slowly through a funnel. Place the stopper on the flask.
- Remove the flask from the bath and place it on a rubber mat. Remove the lead load and manipulate the flask on the mat to release all air bubbles from the flask.
- Return the flask to the bath and check the temperature within the flask. If it is within 0.2 °C of the original temperature inside the flask, take the final reading.
The density of hydraulic cement is calculated using the following formula:
Density, p = mass/displaced volume of cement
Conduct density determination on two samples of cement. If they are 0.03 g/cm. are no different than3, take the average. Otherwise, run three additional determinations until 0.03 g/cm. fail to find a pair of valves inside3,
Record the readings and complete the following data sheet.
|Initial bath temperature, °C|
|final height, cm|
|initial height, cm|
|Displaced volume, cm3|
|Last bath temperature, °C|
|Specific gravity = 64 g/displacement, cm3|
|Average specific gravity of accepted sample result =|