General requirements

Placing and Consolidation

Formwork shall be completed reinforcement, expansion joint material, anchors, block outs add other embedded items shall be placed in position before concrete is cast.

No concrete shall be placed until the reinforcement and formwork have been checked and approved.
The method and equipment used for casting concrete shall be approved by the Engineer.
Concrete must be placed before setting has commenced and must not be subsequently disturbed. Concrete shall be thoroughly worked around reinforcement and embedded around fixtures and into corners of the formwork.
Tampers of approved types shall be used. Mechanical vibrators of approved patterns shall be used wherever possible and especially in all precast work. The consistency of the concrete shall be maintained correct for mechanical vibration and the vibration must not be carried out too long to cause separation of materials and bring cement laitance to the surface. Poker type vibrators shall not be allowed to lie unattended in concrete while switched on, nor shall any vibrating equipment be used for spreading concrete. No concrete shall be dropped during placing from a height exceeding two meters, unless special methods of consolidation of the concrete are approved. The methods shall be such as not to displace the reinforcement. After being placed in position, the concrete must be left absolutely undisturbed by any movements or thrusts while setting. An accurate record must be kept showing dates and items when various portions were cast.
Concrete shall be cast continuously and when in layers, the fresh concrete shall be cast before the under layer has hardened. Construction joints as approved or directed by the Engineer or provided in the drawings shall be placed if concrete cannot be cast continuously.
Wherever waterproof concrete is cast, it shall be compacted by mechanical vibration, so that a dense and homogeneous mass of concrete is obtained throughout every part of the structure. Waterproofing additive directed to be added to the mix shall be applied in shall be so constructed to achieve full continuity. Structures required to be constructed in waterproof concrete shall be completely watertight and any work found to be defective shall be made good by pressure grouting or otherwise as instructed by the Engineer.
In hot dry weather suitable means shall be provided to avoid premature stiffening of concrete placed in contact with hot dry surfaces. Where necessary the surfaces including reinforcement, against which concrete is to be placed shall be shielded from the direct rays of the sun and shall be sprayed with water to prevent excessive absorption by the surfaces of water from the fresh concrete.
03143 Bonding

The hardened concrete of construction joints and joints between concrete structures shall be dampened and thoroughly covered with a coat of cement grout in the same proportion as the concrete mix proportion to be used. The fresh concrete shall be cast before the grout has attained its initial set.