CONSISTANCY TEST OF STANDARD CEMENT PASTE

OVERVIEW

The consistency test for used Vicar Apparatus. In which calculate the consistency of cement and also determine initial sitting and finial setting time.

In the vicat apparatus take mould and penetrate the niddle and the niddle dia. 10mm and the length is 50mm. The niddle should be penetrate 33- 35 mm from top of the mould. For these test temperature is 27+ - 2° c and Humidity 65 + - 5%.

PROCEDURE

(1).  Take 400gm of cement and place it in the enameled tray

(2).  Take 25% of water by weight of dry cement and mixing the water cement and get a cement paste .The cement paste should be ready in 3 to 5 minutes.

(3).  The cement paste fill in the mould, resting upon a glass plate.

(4).  After filling the mould completely smooth the surface of the paste. Making level with top of the mould.

(5).  Place the whole assembly ( mould + Cement paste + glass plate) under the rod bearing plunger

(6).  The vicar plunger rod is free and the plunger niddle penetrate in cement paste.

(7).  Measure the depth of Penetration and record it.

(8).  There test is repeat 2-3 time and verify the percentage of water content. these test repeat until the depth of penetration become 33 to 35 mm

CALCULATION

Calculate percentage of water(p) by weight of dry cement required to prepare cement paste of standard consistency by following formula.

               P   = (W/C) x 100

Where 

W. =  Quantity of water added

C. =  Quantity of Cement used

These test helps to determine inital sitting and finial sitting time of cement and also determine soundness and compressive strength.

PRECAUTION

•   gauging time should be strictly observed.

•   Room temperature should be well maintain as per test requirement.

•   All apparatus should be clean.

•   These test should be away from vibration and distribution area.

TECHNICAL DISCUSS

NAME OF TEST.                                       AMOUNT OF WATER

Soundness test.                                                      .78P. ( p = Consistency of 

                                                                                     Standard cement paste)

Setting time.                                                              .85P ( p = Consistency of

                                                                                      Standard cement paste)

Compressive strength.                                               (P/4+3)% of combined

                                                                                        mass of cement and paste

•   Generally the normal consistency for OPC range from 26 to 33 %.