Er. Hiralal Agrawal EXECUTIVE ENGINEER.

Apparatus:  Concrete cube moulds of 15 cm size in required numbers.  Standard tamping bar (steel) of 16mm diameter with tampering end.  Trowel and hammer.  Lubricants/ Grease,etc.

PROCEDURE:  Apply the lubricants in all the inner sides of the moulds and tight the nuts and bolts and keep the moulds ready.  Collect fresh sample of concrete in a tray.  Keep the moulds on a plane level platform.  Put the concrete samples inside the moulds filling about 1/3 rd of the mould (5 cm thick) and tamper minimum 35 blows with the standard tamping bar.  Then put up the 2 nd and 3 rd layer and tamping each layer with minimum 35 blows.  Further, to reduce voids, the inner sides of the moulds are trowelled and also lightly tampered with hammer from outside.

 After filling the 3 layers, the top surface of the moulds to be leveled/finished and keep that intact for allowing setting for at least 12 hours. In the mean time the name of the item with its identification, etc. is written on the top surface. Moist curing may be required in summer in the above period.  Then the concrete cubes are removed and put under moist curing and finally placed in water tanks for curing after about 24 hours.  The curing should continue for 28 days and then sent to the lab for testing its compressive strength following the procedure as laid down in IS:

CONCRETE MOULDS PREPARATION

TESTING OF CONCRETE CUBES IN COMPRESSION TESTING MACHINE

THANK YOU