CEMENT : DETERMINATION OF CONSISTENCY REFERENCE : IS 4031 – (PART – 4) 1996

OBJECT                  TO    DETERMINE    QUANTITY    OF    WATER    REQUIRED    TO PRODUCE CEMENT PASTE OF STANDARD CONSISTENCY IMPORTANCE       This preliminary test forms base for other tests OF TEST APPARATUS         •     Vicat Apparatus •     Balance (capacity 1000 gms accuracy 0.1 gm) •     Gauging Trowel 100-150 mm long TEMPERATURE  •     Dry Materials, Water and Laboratory         :  27 + 2O  C & HUMIDITY       •     Relative Humidity in Laboratory                 :  65 + 5 % PROCEDURE          On non-porous platform ; •     Prepare cement paste of weighed quantity (300 gm) of cement mixed    with weighed quantity of water (90 gm) using gauging trowel within 3 to 5 minutes before any sign of setting occurs. •     Immediately fill up mould by vicat apparatus with this paste and level  up.     Rest  mould  upon  non-porous  plate  and  shake      to remove penetrated air. Level the top. •     Under plunger rod of vicat apparatus, keep the test block in the mould  together  with  non-porous  plate.  Lower  plunger  needle together to touch top surface of cement block. •     Release plunger quickly and allow it to sink in test block. •     Prepare another sample from same lot by varying water contents and  repeat the process till plunger needle remain embedded in test specimen 5 to 7 mm from  bottom of vicat mould. Note water content  at  this stage.        The  sample  is  said  to  be  of  standard consistency at this water content. CALCULATION                                                        Weight of water in sample Water for standard consistency % =  -----------------------------------------   x 100 Weight of dry cement in sample