Mechanical properties of the materials are find out by applying external forces on them. These are very important properties which are responsible for behavior of a material in its job. The mechanical properties are:
• Impact strength
• Abrasion resistance
Strength of Building Materials
The capacity of a material to resist failure caused by loads acting on it is called as strength. The load may be compressive , tensile or bending. It is determined by dividing the ultimate load taken by the material with its cross sectional area. Strength is an important property for any construction materials. So , to provide maximum safety in strength , factor of safety is provided for materials and it is selected depending on nature of work , quality of material , economic conditions etc.
Hardness of Building Materials
The property of a materials to resist scratching by a herder body. MOHS scale is used to determine the hardness of a materials. Hardness is most important to decide the usage of particular aggregate. It also influences the workability.
Elasticity of Building Materials
The capacity of a material to regain its initial shape and size after removal of load is known as elasticity and the material is called as elastic material. Ideally elastic materials obey Hooke’s law in which stress is directly proportional to strain. Which gives modulus of elasticity as the ratio of unit stress to unit deformation. Higher the value of modulus of elasticity lower the deformations.
When the load is applied on the material , if it will undergo permanent deformation without cracking and retain this shape after the removal of load then it is said to be plastic material and this property is called as plasticity. They give resistance against bending , impact etc.
Examples: steel , hot bitumen etc.
When the material is subjected to load , if it fails suddenly without causing any deformation then it is called brittle material and this property is called as brittleness.
Examples: concrete , cast-iron etc.
If a material is subjected to repeated loads , then the failure occurs at some point which is lower than the failure point caused by steady loads. This behavior is known as fatigue.
If a material is subjected to sudden loads and it will undergo some deformation without causing rupture is known as its impact strength. It designates the toughness of material.
The loss of material due to rubbing of particles while working is called abrasion. The abrasion resistance for a material makes it durable and provided long life.
Creep the deformation caused by constant loads for long periods. It is time dependent and occurs at very slow rate. It is almost negligible in normal conditions. But at high temperature conditions creep occur rapidly.