Mixing The Materials Of Concrete

The process of rolling, folding and spreading of particles is known as the mixing of concrete.

The materials of concrete should be mixed thoroughly so that there is uniform distribution of materials in the mass of concrete. The through mixing also ensures that cement water paste completely covers the surfaces of aggregates. The mixing of materials of concrete can be done either with hand or with the help of a machine.

Hand Mixing: For hand Mixing, the materials are stacked on a water-tight platform, which may be either of wood, brick or steel.

The materials should be thoroughly mixed, at least three times, in dry condition before water is added. The prepared mix should be consumed in 30 minutes after adding water. The mixing by hand is allowed in case of small worked or unimportant works where small quantity of concrete is required. For important works, if hand mixing is to be adopted, it is advisable to use 10 per cent more cement than specified.

Machine mixing: For machine mixing, all the materials of concrete including water, are collected in a revolving drum and then the drum is rotated for a certain period. The resulting mix is then taken out of the drum. The features of machine mixing are as follows:


(1) It is found that mixing the materials of concrete with the help of machines is more efficient and it produces concrete of better quality in a short time.

(2) The mixers of various types and capacities are available in the market. They may either be of tilting type or non-titling type. They are generally provided with power-operated loading hoppers. For small works, a mixer capab