If a piece of material neither expands nor contracts in volume when subjected to stress, then the Poisson’s ratio must be:

A) 0
B) 0.25
C) 0.5
D) 1

According to IS 456:2000, Clause 6.2, Poisson’s ratio is defined as the ratio of transverse strain to axial strain. For a material that does not change in volume under stress, the transverse and axial strains must be equal in magnitude but opposite in sign. Therefore, the Poisson’s ratio for such a material must be 0.5.

Table 6 of IS 456:2000 provides typical Poisson’s ratio values for common materials used in concrete structures. For example, the Poisson’s ratio for structural steel is 0.3 and for concrete is 0.2.

The correct option is C) 0.5

This indicates that the material is incompressible and does not change volume when loaded in one direction. Rubber exhibits such behavior and has a Poisson’s ratio of around 0.5.