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
& 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
• 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