Tensile Strength of Concrete

Q. The modulus of rupture of concrete gives

1. the direct tensile strength of the concrete
2. the direct compressive strength of the concrete
3. the tensile strength of the concrete under bending
4. the characteristic strength of the concrete

Q. The flexural tensile strength of M25 grade of concrete in N/mm${}^2$ as per IS:456-2000 is _______.

1. 3.5

Q. Modulus of elasticity of concrete is increased with

1. Higher W/C ratio
2. Shorter curing period
3. Lesser vibration
4. Increase in age

Q. The ratio of splitting tensile strength and design compressive strength of M25 concrete is

1. 0.14
2. 0.2
3. 0.31
4. 0.1

Q. Modulus of elasticity of M25 grade concrete in MPa is

1. 25000
2. 36000
3. 45600
4. 54000

Q. At what stress does the first flexural crack appear in RCC beams made of M25 grade concrete?

1. 3.0 MPa
2. 3.5 MPa
3. 4.0 MPa
4. 4.5 MPa

Q. Which one of the following predicts the effective modulus of elasticity of concrete?

1. $\frac{E_c}{1+\theta }$
   where $E_c$ is short-term elastic modulus and $\theta$ is the ultimate creep coefficient
2. $\frac{E_c}{1+2\theta }$where $E_c$ is short-term elastic modulus and $\theta$ is the ultimate creep coefficient\theta}
3. $\frac{E_c}{1+3\theta }$
   where $E_c$ is short-term elastic modulus and $\theta$ is the ultimate creep coefficient
4. $\frac{E_c}{1+5\theta }$
   where $E_c$ is short-term elastic modulus and $\theta$ is the ultimate creep coefficient

Q. For M25 concrete with creep coefficient of 1.5, the long-term static modulus of elasticity (expressed in MPa) as per the provisions of IS:456-2000 is ________.

1. 10000

Q. The deformation in concrete due to sustained loading is

1. creep
2. hydration
3. segregation
4. shrinkage

Q. When a specimen of M25 concrete is loaded to a stress level of 12.5 MPa, a strain of $500\times {10}^{-6}$ is recorded. If this load is allowed to stand for a long time, the strain increases to $1000\times {10}^{-6}$. In accordance with provisions of IS: 456-2000, considering the long-term effects, the effective modulus of elasticity of the concrete (in MPa) is _______.

1. 12500

Q. What is the value of flexural strength of M 25 concrete?

1. 4.0 MPa
2. 3.5 MPa
3. 3.0 MPa
4. 1.75 MPa

Q. The flexural strength of M-30 concrete as per IS : 456-2000 is

1. 3.83 MPa
2. 5.47 MPa
3. 21.23 MPa
4. 30.0 MPa