Reinforcement Cement Concrete (General Engineering) (SSC JE)

According to IS : 456-2000–
• Modulus of elasticity of steel is 200 kN/mm² or 2×10⁵ N/mm² .

Assumption as per IS 456 : 2000.
(a) Plane section normal to the axis remain plane after bending.
(b) The maximum strain in concrete at outermost compression fiber is taken as 0.0035 in bending.
(c) The relationship between the stress strain distribution in concrete is assumed to be parabolic.
(d) The tensile strength of the concrete is neglected.
(e) The relationship between the compressive stress distribution in concrete and the strain in concrete may be assumed to be rectangle, trapezoid, parabola or any other shape which results in predication of strength in substantial agreement with the result of test.
(f) The maximum strain in the tension reinforcement in the section at failure shall not less than.

Types of prestressing–
(i) Hydraulic prestressing
(ii) Thermal prestressing (Thermo-electric prestressing)
(iii) Chemical prestressing
(iv) Mechanical prestressing
(v) External prestressing
(vi) Internal prestressing.

As per IS 456 : 2000 - under normal circumstances the maximum cement content (including fly ash and slag) allowed is 450 kg/m3
• Cement content not including fly ash and ground granulated blast furnace slag in excess of 450 kg/m3 should not be used unless special consideration has been given in the design to the increased risk of cracking due to drying shrinkage in thin sections or to early thermal cracking and to the increased risk of damage due to alkali silica reactions.

• The failure of column depends upon its slenderness ratio. The load required to cause above mentioned failures decreases as the length of
compression member increases, the cross-sectional area of the member being constant. Therefore, columns are commonly classified as short and long columns.

Size of aggregate is increased from 20mm to 40mm the specific surface area decrease, due to which lesser amount of cement paste is required. Adjustments to minimum cement concrete for aggregates other than 40mm nominal maximum size aggregate as per IS : 456 : 2000.

Reinforced concrete as an economic building material, is resist many types of loading. Concrete resists compression and steel reinforcement resists tension forces.
Advantages of Reinforced Concrete–
• The monolithic character of reinforced concrete gives it more rigidity.
• Maintenance cost of RCC is practically nil.
• It has good resistance to damage by fire and weathering (because of concrete)
• It is durable and RCC prevent steel from rusting.