Density of Concrete

Density of Concrete

1.   Purpose:    The bulk density measure is used for determining the weight per cubic meter of freshly mixed concrete (density) from which the yield of concrete per cubic meter can be calculated.

2.   Procedure:      Methods of sampling and analysis of concrete

 i.      Take freshly mixed concrete from transit mixer by using wheel borrow.

ii.   Fill the cylindrical measure with concrete as soon as practicable after mixing.

iii.  Fill the cylindrical measure with concrete in layers approximately 5 cm deep and each layer shall be compacted.

iv.  While compacting the concrete the standard tamping bar shall be distributed in uniform manner over the cross section of the measure.

v.    The number of strokes per layer is 60 for 10 liters cylinder and 120 for 20 liters cylinder.

vi.  The exterior surface of the cylinder shall be tapped 10to 15 times or until no large bubbles of air appear onthe surface of the compacted layer.

vii.   Strike-off the top surface and finish it smoothly with a flat cover plate.

viii.  Clean all excess concrete from the exterior and weigh the filled measured.

ix.   Density of concrete (W1): The weight per cubic meter of concrete shall be calculated by dividing the weight of fully compacted concrete in the cylindrical measure by the capacity of measure in kg/cu.m (W1).

x.    Yield of concrete (V2) : The volume of concrete produced per cum. shall be calculated as follows.

xi.  V2= Wc+ Wf + Wca+ Ww

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              W1

 Wc= Weight of cement, kg

Wf = Weight of fine aggregate, kg

Wca= Weight of coarse aggregate, kg

Ww= Weight of water, kg