Slump test is performed to measure the plasticity of concrete.

Plasticity of Concrete:
The plasticity of concrete refers to its ability to deform without cracking or breaking. It is an important property of concrete as it determines its workability and ease of placement. The slump test is specifically designed to measure the plasticity of concrete.

Slump Test Procedure:
The slump test involves the following steps:

1. Preparation: The test requires a slump cone, a tamping rod, and a base plate. The cone is filled with freshly mixed concrete in three layers, each layer being tamped 25 times with the tamping rod.

2. Slump Measurement: Once the cone is filled, it is lifted vertically, allowing the concrete to spread and settle. After a brief period of time, the cone is removed, and the settlement of the concrete is measured.

3. Reading the Slump: The slump is measured by subtracting the height of the concrete after settlement from the original height of the cone. This difference gives an indication of the plasticity of the concrete.

Significance of Slump Test:
The slump test provides valuable information about the workability and consistency of concrete. It helps in assessing the water-cement ratio, the amount of admixture required, and the overall quality of the concrete mixture. The test is widely used in construction projects to ensure that the concrete meets the desired specifications and can be easily placed and compacted.

Other Options:
a) Young's Modulus of Concrete: Young's modulus is a measure of the stiffness of a material. It is not determined by the slump test.

c) Compressive Stress of Concrete: The slump test does not directly measure the compressive stress of concrete, which is typically determined through separate tests such as the compression test.

d) Tensile Stress of Concrete: The slump test does not provide any information about the tensile stress capacity of concrete. Tensile strength is usually evaluated using different tests like the split tensile test or the flexural strength test.

In conclusion, the slump test is performed to measure the plasticity of concrete. It helps in assessing the workability and consistency of concrete, ensuring that it can be easily placed and compacted.