CEMENT : DETERMINATION OF SETTING TIME REFERENCE : IS 4031 – (PART – 5) 1996

OBJECT                  TO DETERMINE INITIAL AND FINAL SETTING TIME OF CEMENT

IMPORTANCE       The object is to distinguish between,quick setting and normal setting

OF TEST                 time and to detect the deterioration due to storage.

APPARATUS         •     Vicat Apparatus

•     Balance (capacity 1000 gms, accuracy 0.1 gm)

•     Annular attachment of Vicat Apparatus

TEMPERATURE    •     Dry Materials, Water and Moulding Room :   27 + 2O  C

& HUMIDITY           •     Relative Humidity in Laboratory                 :  65 + 5 %

PROCEDURE         On a non-porous platform

•     Mix neat cement with  enough water  to give a paste of Standard

Consistency.

•     Start stop watch immediately on adding water to cement. Note

Stop watch reading (To)

•     Rest Vicat mould on non-porous plate and fill it completely with cement paste.  Level of top surface and expel air by shaking.

•     Place test block with mould under the rod bearing needle of Vicat apparatus  and  bring  rod  level                                           with  top  of  test  specimen. Release needle slowly and let it penetrate in the test block.

•     Repeat the procedure until needle stops of distance  of  (5 + 0.5) mm   from base of test block. Read the stop watch and note the time (T1).

•     Replace  needle  by  annular  attachment.  Repeat  procedure  of releasing the needle till needle makes an impression on top of test block while attachment fails to do so.  Read the stop watch and note time (T2).

CALCULATION      Initial Setting Time (IST)   = (T1 – T0)

Final  Setting Time (FST) = (T2 – T 0) REPORTING          Report IST & FST to nearest 5 minutes