Determination Of The Characteristic Strength Properties Of Mild Steel Reinforcement
[A CASE STUDY OF ILORIN METROPOLIS]

2.3 STRENGTH OF MATERIALS
The strength of a material is the ability to withstand externally applied forces without failing. In the area of strength of materials, Problems are primarily of two types: analysis and design. Problems of analysis could involve finding the greatest load that may be applied to a given body without exceeding specified limiting values of stress and strain. They could also involve determining load induced stresses and strains for comparison with limiting values.
Engineering materials can therefore with limiting values. Under the following properties;
2.3.1 Stiffness
The property that enables a material to withstand high stress without great strain. It is a resistance to any sort of deformation. Stiffness of a material is function of the modulus of elasticity E. A material such as steel having a high value of E will deform less under load.
2.3.2 Elasticity
It is the property of material that enables it to regain its original dimensions after removal of a deforming load. There is no known material that is completely elastic in all ranges of stress. Steel is an elastic material only up to the elastic limit. Hence the determination of the elastic limit establishes the elastic range or the limit of elasticity.
2.3.3 Ductility
A material which will undergo considerable plastic deformation tensile load before actual rupture is said to be ductile. Ductility is characterized by the percentage elongation of the gauge length of the specimen during the tensile test and by the percent reduction in area of the cross section at the plane of fracture. A metal is said to be ductile if the percent elongation is greater than about 5%.
2.3.4 Brittleness
This implies the absence of any plastic deformation to failure. A brittle material is neither ductile nor malleable and will fail suddenly without warning. Brittle materials such as cast-iron, concrete, stone are comparatively weak in tension and are generally not subjected to a tension test. They are usually tested in compression.
2.3.5 Malleability  
This is the property of a material enabling it to undergo considerable plastic deformation under compressive load before actual rupture. Most materials that are very ductile are also quite malleable.
2.3.6 Toughness
The property of a material enabling it to endure high impact loads or sock loads. When a body is subjected to an impact load, some of the energy of the blow is transmitted and absorbed by the body. The measure of toughness is equal to the area under the stress stain curve from the origin through the rupture point.