Precautions while Placing Concrete
The given below are the precautions that must be observed during placing of concrete in order to get required strength of the concrete.
(a) The concrete would not be thrown from a height of more than 1 m to prevent segregation.
(b) The concrete would be deposited in horizontal layers of uniform thickness not exceeding 45 cm for mass concrete and 30 cm for reinforced concrete.
(c) No person should be permitted to walk over freshly laid concrete.
(d) The old surface would be made rough, cleaned and cement grouted before placing any new layer of concrete.
(e) The alignment of reinforcement and formwork should not be disturbed in any case when concrete is placed in RCC members.
(f) Placement of concrete would be discontinued during rainy periods.
(g) The laitance should be removed, i.e. squeezed out, before placing new concrete.
(h) Concrete should be laid incessantly in order to avoid the formation of irregular and unsightly lines.
(i) The internal surfaces of the formwork would be oiled in order to prevent concrete from sticking to sides.
(j) The placing of concrete would begin widthwise in reinforced cement concrete slabs.