Slump of concrete for RCC slab

Slump test is used to measure the workability of concrete. Workability is defined as the ease and homogeneity with which a freshly mixed concrete can be mixed, placed, compacted and finished. The slump test is commonly used for measuring the consistency of fresh concrete before it sets.

For an RCC slab, the ideal slump of concrete should be between 75-100 mm. The reason for this is as follows:

Factors affecting the slump of concrete:

1. Water-cement ratio: The amount of water used in the mix affects the workability of the concrete. The higher the water-cement ratio, the higher the slump. However, a high water-cement ratio also reduces the strength of the concrete.

2. Aggregate size and shape: The size and shape of the aggregate affects the workability of the concrete. Smaller aggregates and rounded aggregates have a higher workability than larger and angular aggregates.

3. Admixtures: Admixtures are used to modify the properties of concrete. They can be used to increase or decrease the workability of the concrete.

Why 75-100 mm is the ideal slump for RCC slab?

1. Workability: An RCC slab requires a high workability concrete to ensure that it is properly compacted and does not have any voids. A slump of 75-100 mm ensures that the concrete is easy to place and compact.

2. Reinforcement: RCC slabs have a high amount of reinforcement. A high slump concrete ensures that the reinforcement is properly covered with concrete and there are no voids around the reinforcement.

3. Consolidation: RCC slabs require consolidation to ensure that there are no voids in the concrete. A high slump concrete is easy to consolidate and ensures that there are no voids in the concrete.

In conclusion, the ideal slump of concrete for an RCC slab should be between 75-100 mm. This ensures that the concrete is easy to place, compact, and consolidate, and ensures that there are no voids in the concrete.