Concrete Technology || Top 50 Interview Question with Solution ||

1. What is concrete?
Concrete is a composite material comprising cement, water, coarse and fine aggregates, and sometimes admixtures.
2. What is the formula for calculating the modulus of elasticity of concrete?
The formula for calculating the modulus of elasticity of concrete is E = σ/ε, where E is the modulus of elasticity, σ is the stress, and ε is the strain.
52. What is the formula for calculating the unit weight of concrete?
The formula for calculating the unit weight of concrete is γ = M/V, where γ is the unit weight, M is the mass, and V is the volume.
53. What is the formula for calculating the volume of concrete?
The formula for calculating the volume of concrete is V = l × w × h, where l is the length, w is the width, and h is the height.
54. What is the formula for calculating the total water content in concrete?
The formula for calculating the total water content in concrete is W = (weight of water + weight of admixtures)/weight of cement.
55. What is the formula for calculating the weight of cement in concrete?
The formula for calculating the weight of cement in concrete is W_c = V × γ_c / (1 + W/C), where W_c is the weight of cement, V is the volume of concrete, γ_c is the unit weight of cement, and W/C is the water-cement ratio.
56. What is the formula for calculating the void ratio of aggregate in concrete?
The formula for calculating the void ratio of aggregate in concrete is e = (V_v/V_s) × 100%, where e is the void ratio, V_v is the volume of voids, and V_s is the volume of solids.
58. What is the formula for calculating the strength reduction factor of concrete due to cracking?
The formula for calculating the strength reduction factor of concrete due to cracking is φ_s = (1.0 + ε_c) / (1.0 + ε_t), where φ_s is the strength reduction factor, ε_c is the strain at cracking, and ε_t is the ultimate strain.
59. What is the formula for calculating the modulus of rupture of concrete?
The formula for calculating the modulus of rupture of concrete is f_r = 2 × P × L / (w × d^2), where f_r is the modulus of rupture, P is the maximum load, L is the span length, w is the width, and d is the depth.
60. What is the formula for calculating the yield strength of reinforcement in concrete?
The formula for calculating the yield strength of reinforcement in concrete is f_y = A_s × f_yt, where f_y is the yield strength, A_s is the area of reinforcement, and f_yt is the yield strength of the reinforcement material.
61. What is the formula for calculating the modulus of elasticity of steel reinforcement in concrete?
The formula for calculating the modulus of elasticity of steel reinforcement in concrete is E_s = 29,000 × √f_y, where E_s is the modulus of elasticity and f_y is the yield strength of the reinforcement.
62. What is the formula for calculating the flexural strength of reinforced concrete?
The formula for calculating the flexural strength of reinforced concrete is f_b = 0.87 × f_c × (A_s × d) / (b × (h - d/2)), where f_b is the flexural strength, f_c is the compressive strength, A_s is the area of reinforcement, d is the effective depth, b is the width, and h is the total depth.
63. What is the formula for calculating the moment of inertia of a rectangular section?
The formula for calculating the moment of inertia of a rectangular section is I = bh^3/12, where I is the moment of inertia, b is the width, and h is the height.
65. What is the formula for calculating the depth of neutral axis in a reinforced concrete beam?
The formula for calculating the depth of neutral axis in a reinforced concrete beam is c = 0.5 × (h - (h^2 - (2M/bf × f_c))^(1/2)), where c is the depth of neutral axis, h is the total depth, M is the bending moment, b is the width, and f_c is the compressive strength.
66. What is the formula for calculating the reinforcement ratio in a reinforced concrete beam?
The formula for calculating the reinforcement ratio in a reinforced concrete beam is ρ = A_s/(b × d), where ρ is the reinforcement ratio, A_s is the area of reinforcement, b is the width, and d is the effective depth.
67. What is the formula for calculating the development length of reinforcement in concrete?
The formula for calculating the development length of reinforcement in concrete is L_d = α × d × f_y / f_c, where L_d is the development length, α is the factor depending on the type of reinforcement and the bond condition, d is the diameter of reinforcement, f_y is the yield strength of reinforcement, and f_c is the compressive strength.
68. What is the formula for calculating the spacing of stirrups in a reinforced concrete beam?
The formula for calculating the spacing of stirrups in a reinforced concrete beam is s = 0.75 × d × √f_c / fy, where s is the spacing of stirrups, d is the effective depth, f_c is the compressive strength, and f_y is the yield strength.