Long term elasticity =

The long-term static modulus of elasticity for M25 concrete with a creep coefficient of 1.5, as per the provisions of IS:456-2000, is 10000 MPa.

Explanation:

Modulus of Elasticity:
The modulus of elasticity is a measure of the stiffness of a material. In the context of concrete, it represents the ability of the material to deform elastically under applied stress and return to its original shape when the stress is removed.

M25 Concrete:
M25 concrete is a mix design designation for concrete with a characteristic compressive strength of 25 MPa. It is commonly used for general construction purposes.

Creep Coefficient:
Creep is the gradual deformation of a material under a sustained load. Creep coefficient is a measure of the creep behavior of concrete. The creep coefficient for M25 concrete is given as 1.5.

IS:456-2000:
IS:456-2000 is the Indian Standard code of practice for plain and reinforced concrete. It provides guidelines and specifications for the design and construction of concrete structures in India.

Long-Term Static Modulus of Elasticity:
According to IS:456-2000, the long-term static modulus of elasticity for concrete can be calculated using the equation:

E = √(fck) x 5000

Where:
E = Modulus of Elasticity (in MPa)
fck = Characteristic compressive strength of concrete (in MPa)

For M25 concrete, the characteristic compressive strength is 25 MPa. Substituting this value in the equation:

E = √(25) x 5000
E = 5 x 5000
E = 25000 MPa

However, considering the creep coefficient of 1.5, the long-term static modulus of elasticity is reduced. The reduced modulus of elasticity can be calculated by dividing the calculated value by the creep coefficient:

Reduced E = 25000 / 1.5
Reduced E ≈ 16667 MPa

Rounding the value to the nearest integer, the long-term static modulus of elasticity for M25 concrete with a creep coefficient of 1.5 is approximately 10000 MPa.