Laboratory Tests

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  1. Asked: In:

    How to conduct a soundness tests on cement?

    Nimesh Gajera

    Nimesh Gajera

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    Nimesh Gajera Learner

    The cement considers unsound if it undergoes a large change in volume (expansion) that causes cracking of hardened cement paste when it is under the condition of restraint. Apparatus Required: Le-Chateliers Apparatus, Water bath, Vernier Caliper, Weighing Scale. Procedure : 1. Place the lightly oileRead more

    The cement considers unsound if it undergoes a large change in volume (expansion) that causes cracking of hardened cement paste when it is under the condition of restraint.

    Apparatus Required: Le-Chateliers Apparatus, Water bath, Vernier Caliper, Weighing Scale.

    Procedure :

    1. Place the lightly oiled mold on a lightly oiled glass sheet and fill it with cement paste formed by gauging cement with 0.78 times the water required to give a paste of standard consistency.

    2. Cover the mold with another piece of lightly oiled glass sheet, place a small weight on this covering glass sheet and immediately submerge the whole assembly in water at a temperature of 27 ± 2°C and keep there for 24 hours.

    3. Measure the distance separating the indicator points to the nearest 0.5 mm. Submerge the mold again in water at the temperature prescribed above.

    4. Bring the water to boiling, with the mold kept submerged, in 25 to 30 minutes, and keep it boiling for three hours. Remove the mold from the water, allow it to cool, and measure the distance between the indicator points.

    5. The difference between these two measurements indicates the expansion of the cement. This must not exceed 10 mm for ordinary, rapid hardening, and low heat Portland cements. If in case the expansion is more than 10 mm as tested above, the cement is said to be unsound.

    Observation And Recording:

    Soundness/expansion of cement = L1-L2
    L1=Measurement taken after 24 hours of immersion in water at a temp. of 27 ± 20C
    L2=Measurement taken after 3 hours of immersion in water at boiling temperature.
    Calculate the mean of two values to the nearest 0.5 mm.

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  2. Asked: In:

    How to Determine the Specific Gravity of Chemicals using Pycnometer? 

    Rohan Chaugule

    Rohan Chaugule

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    Rohan Chaugule Expert

    Steps PROCEDURE Clean and dry the density bottle wash the bottle with water and allow it to drain. Wash it with alcohol and drain it to remove water.  Wash it with ether, to remove alcohol and drain ether. Weigh the empty bottle with stopper (W1) Take about 10 to 20 gm of oven soil sample which is cRead more

    Steps

    PROCEDURE

    1. Clean and dry the density bottle
    1. wash the bottle with water and allow it to drain.
    2. Wash it with alcohol and drain it to remove water.
    3.  Wash it with ether, to remove alcohol and drain ether.
    1. Weigh the empty bottle with stopper (W1)
    2. Take about 10 to 20 gm of oven soil sample which is cooled in a desiccator. Transfer it to the bottle. Find the weight of the bottle and soil (W2).
    3. Put 10ml of distilled water in the bottle to allow the soil to soak completely. Leave it for about 2 hours.
    4. Again fill the bottle completely with distilled water put the stopper and keep the bottle

        under constant temperature water baths (Tx0 ).

    1. Take the bottle outside and wipe it clean and dry note. Now determine the weight of the bottle and the contents(W3).
    2. Now empty the bottle and thoroughly clean it. Fill the bottle with only disttiled water and weigh it. Let it be W4at temperature (Tx0C).
    3. Repeat the same process for 2 to 3 times, to take the average reading of it.

      OBSERVATIONS

    S. No. Observation Number 1 2 3
    1

    2

     

    3

     

    4

    		 Weight of density bottle (W1 g)

    Weight of density bottle + dry soil (W2 g)

    Weight of bottle + dry soil + water at temperature T x0 C (W3 g)

    Weight of bottle + water (W4 g) at temperature Tx0 C

    		      
      Specific gravity G at  Tx0 C      
      Average specific gravity at Tx0C      

    INTERPRETATION AND REPORTING

      Unless or otherwise specified specific gravity values reported shall be based on water at 270C. So the specific gravity at 270C = K�Sp. gravity at Tx0C.

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  3. Asked: In:

    What is gradation limits for 6mm aggregates?

    Gopal Mishra

    Gopal Mishra

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    Gopal Mishra

    you can refer to this article https://theconstructor.org/practical-guide/grading-limits-for-aggregates/2383/

    you can refer to this article https://theconstructor.org/practical-guide/grading-limits-for-aggregates/2383/

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