Influence of horizontal construction joint on the flexural behaviour of reinforced concrete slabs

الملخص EN

Some concrete casting contractors fall in certain mistake during casting of reinforced concrete slabs in field by casting them in two layers.

The first layer is usually casted up to cover the reinforcement steel mesh to allow the concrete trolley (which carries the fresh concrete) to move easily above the rough surface of the slab (after hardening) for casting the second layer without any destruction of the arrangement of steel mesh.

This technique of casting creates a horizontal joint which is considered as a plane of weakness which may be subjected to leakage, deterioration, and possible failure due to tensile or shear stresses.

This paper concentrates on the effect of the horizontal joint and the type of the different bonding materials (which are used to bond the two layers) on the flexural response of reinforced concrete slab.

Test results show many surprises as being of horizontal joint in reinforced concrete slabs do not affect the performance of slabs in flexure.

Moreover, jointed slabs with and without bonding materials recorded higher values of ultimate load carrying capacities, stiffness, ductility, flexural toughness, and less deflection compared with the reference slab (solid slab without joint).