Specific Gravity of Cement


The determination of specific gravity is usually described as the ratio between the mass of a specified volume of substance and weight of an equivalent volume of water. To resolve the specific gravity of cement, kerosene which do not react when mixed with cement is utilized.

Apparatus

Le Chaterlier”s flask, weighing balance, kerosene (free from water).

Le Chaterlier”s flask, is constructed out of thin glass having a bulb at the base. The full capacity of the bulb is approximately 250 ml. The bulb is approximately 7.8 cm in mean diameter. The stem is measured in millimeters. The zero graduation is at the space of 8.8 cm from the top of the bulb. At 2 cm from the zero, nearby is another bulb of length 3.5cm and capacity 17 ml. At 1 cm from bulb, the stem is noted with 18 ml and is marked up to 24 ml. The segment greater than 24ml mark is in the shape of a funnel of diameter 5cm.

Procedure

(I) Dehydrate the flask cautiously and fill up  kerosene or we can use naptha as well to a mark on the stem between zero and 1 ml.

(II) Document the intensity of the liquid in the flask as primary reading.

(III) Keep a weighted quantity of cement (about 60 gm) inside the flask so that the level of kerosene raises up to about 22 ml mark, good caution should be taken in order to avoid splashing and to observe that cement does not stick on to the sides of the greater than level of liquid.

(IV) After keeping cement to the flask, roll the flask slowly in a bent position to force out air until no additional air bubble raises up to the surface of the liquid.

(V) Mark down the new liquid level as concluding reading.

Observation and Calculations

(i) Weight of cement utilized =W gm

(ii)First reading of flask =V1 ml

(iii)Last reading of flask =V2 ml

(iv)Volume of cement particle= V2-V1 ml

(v) Weight of equal of water= ( V2-V1) x specific weight of water.

Specific gravity of cement = (Weight of cement/ Weight of equal volume of water)

= W/(V2-V1)

Note:

(I) Duplicate determination of specific gravity should agree within 0.01.

(II) To obtain more accurate result, the flask has to be held in a constant temperature before each reading is taken.

Result

Specific gravity of a sample of cement =