Factors Affecting Shear Strength of Concrete

 Shear strength of any material is the maximum shear load a body can withstand before failure occurs divided by its cross sectional area.

Shear strength of concrete is affected by following factors:

1.Tensile strength of concrete: The inclined cracking load in shear is a function of the tensile strength of concrete.
2.Longitudinal reinforcement ratio: The shear strength of the RC beams is found to drop significantly if the longitudinal reinforcement ratio is decreased below 1.2–1.5 per cent.

3.Shear span to effective depth ratio: Its effect is pronounced when av /d is less than two and has no effect when it is greater than six.

4.Lightweight aggregate concrete: They reduce tensile strength than concrete with normal aggregates.

5.Size of beam: As the depth of the beam increases, the shear stress at failure decreases.

6.Axial forces : Axial tension decreases the inclined cracking load and the shear strength of concrete, whereas axial compression does just the opposite.

7.Size of coarse aggregate: Increasing the size of coarse aggregates increases the roughness of the crack surfaces, thus allowing higher shear stresses to be transferred across the cracks.

Read: Types of Shear Reinforcements