Properties of Construction Materials
Properties of Construction Materials: Numerous naturally occurring materials have been used in building from prehistoric times. Soil (earth), stone, rock, wood, and water are only a few of the ingredients. These materials are plentiful in nature. While some of these materials may be utilized directly without further processing, others may need further refining to meet the precise requirements.
Natural resources are utilized as raw materials to manufacture building materials, for example, clay is utilized to manufacture bricks and tiles. These materials may be employed in a variety of technical applications.
To guarantee correct use of these building materials, it is necessary to understand their varied qualities.
The properties of building materials, in particular, are discussed here.
Engineering Materials Classification
Civil engineering materials, electrical engineering materials, and mechanical engineering materials are all generically classed as engineering materials. Certain materials, however, may be utilized in other areas as well.
Civil engineering materials include soils, building stones, bricks and clay products, lime, cement, concrete, mortar, wood, metals, and alloys.
Electrical engineering materials include conductors, semi-conductors, insulators, and magnetic materials.
The primary materials used in mechanical engineering are cast iron, steel, and lubricating materials.
In one or more of the fields, metals, alloys, ceramic materials, and organic matter are utilized.
Qualities of Construction Materials
The following summarizes the properties of building materials used in engineering projects:
- Physical characteristics
- Mechanical characteristics
- Electrical characteristics
- Magnetic characteristics
- Chemical characteristics
The following sections discuss the properties of construction materials that are significant to building construction.
Physical characteristics of construction materials
The following are significant physical qualities of construction materials:
Density of the Bulk
Bulk density is the mass of a substance per unit volume in its native condition. This is calculated by dividing the mass of the substance by its volume. The bulk density of a material determines the majority of its technical attributes, such as strength, conductivity, and so on. The unit is kN/m3. Granite has a bulk density of 25 to 27 kN/m3, limestone has a bulk density of 18 to 24 kN/m3, and pinewood has a bulk density of 5 to 6 kN/m3.
Density is defined as the mass per unit volume of a homogenous substance. Steel has a density of 78.5 kN/m3. The density index is the ratio of the bulk density to the density of the material. Clearly, the density index of the majority of construction materials is less than one.
It is a material’s resistance to chemical attack by acids, alkalis, salt solutions, and gaseous substances.
Resistance to fire
Fire resistance refers to a material’s ability to withstand the action of high temperatures without losing strength or altering the structure’s original form. Wood, as a building material, is very flammable. These materials should be treated to withstand extreme heat and fire.
Resistance to Frost
When the spaces in a construction material are filled with water and exposed to sub-zero temperatures, a process called freezing occurs. Thus, frost resistance refers to a material’s capacity to withstand freezing and thawing. It is dependent on the material’s density and degree of saturation with water. By and large, thick materials are resistant to frost.
Resistance to spalling
Spalling resistance is a term that refers to materials that can withstand repeated temperature fluctuations. This is mostly determined by the material’s coefficient of linear expansion.
Resistance to the weathering
It is a material’s ability to withstand alternating wet and dry environments without degrading. Weathering alters the contour of the object and reduces its mechanical strength.
A substance’s porosity is defined as the volume of voids or pores divided by the total volume of the substance. The denser the material, the less porous it will be. The bulk density, water absorption, thermal conductivity, strength, and durability of a material are all dependent on its porosity.
Absorption of Water
Water absorption refers to a material’s capacity to absorb and hold water. It is dependent on the material’s porosity, the size and shape of the pores.
Permeability of Water
It is the ability of a substance to let the passage of water under pressure. For instance, wood may have a higher water permeability than steel.
A material’s ability to absorb water vapor from the air is referred to as its absorption capacity. It is determined by the material’s porosity, the ambient temperature, and the type of the substance.
It is the ratio of a material’s compressive strength when completely soaked to its compressive strength when dry. Water-resistant materials have a coefficient of softening greater than 0.8.
The capacity of a material to withstand the continuous action of atmospheric and other conditions is referred to as its durability. For instance, a building’s durability is determined by the resistance supplied by the various materials used to create it under varying situations.
Mechanical characteristics of construction materials
The following sections describe various mechanical characteristics of materials:
Abrasion is a characteristic of a material that describes how well it resists the force applied by a moving load.
Elasticity refers to a material’s capacity to regain its original form after the removal of an external force. If a material reverts to its former form after being stretched, it is said to be completely elastic. Steel, copper, and aluminum, for example, may be classified as fully elastic materials under specified deformation limitations. Thus, each material has a critical load value, sometimes referred to as the elastic limit, which results in the partial breakdown of elasticity. Excessive loading results in permanent deformation of the material.
Plasticity is the characteristic of a material that allows a stretched material to keep its distorted state long after the external force that generated the distortion is removed. Most materials become plastic when subjected to high stresses.
Ductility refers to a material’s capacity to be pulled into a wire by external pressures. As a result, a ductile material may sustain significant deformation without failing. During the extension phase, a ductile material may exhibit a degree of elasticity in addition to a high degree of plasticity. Copper, aluminum, and gold are all examples of ductile materials.
Brittleness is a quality of a material in which it is incapable of undergoing significant deformation in response to an external stress yet spontaneously fractures or ruptures. This is the most detrimental feature of a building material. Glass, porcelain, and other fragile materials are examples.
Malleability refers to a material’s ability to be evenly stretched or broadened without rupture when hammered or rolled. A malleable material is one that is very malleable. This feature is widely used in forging, hot rolling, and drop stamping, among other applications. Wrought iron, copper, and mild steel are all malleable materials.
The strength of a material is measured by the greatest stress that it can endure before failing. The definition of strength is dependent on the nature of the loading and the type of the stress. There is no one value that can be used to quantify strength in all circumstances.
For instance, a structural part that is well constructed is unlikely to break under typical working circumstances. This is guaranteed when the member’s material is sufficiently robust to sustain the force applied to it.
The hardness of a substance refers to its resistance to penetration by another substance or item. Diamond is the hardest substance known to man, whereas talcum is the softest.
Toughness is a quality of a substance that allows it to absorb energy without breaking. This is a very valuable feature of a material that applies to both cyclic and instantaneous loads.
Stiffness is the quality of a material that permits it to resist a great amount of stress without deforming significantly. A material’s stiffness is determined by its elastic property. For instance, excessive deformations are undesirable in a structural part, and the material should be rigid enough to bear the load.
When a material is repeatedly exposed to fluctuating stress, it will fail at a stress that is much less than the stress necessary to create a fracture under stable loads. This is referred to as weariness.
Stability is the characteristic of a member that allows it to retain its overall equilibrium, preventing it from collapsing completely. For instance, when a component member composed of a certain material is exposed to a force acting along its axis, it is just long enough to avoid buckling.
Electrical characteristics of construction materials
Physical properties and mechanical properties are important for solid materials, which are used as building construction materials. However, knowledge of electrical, magnetic and chemical properties is also needed to deal with construction activities of buildings under different environments. Electrical properties of materials are discussed briefly below.
The material’s property is to impede the passage of electricity through it. It is a very beneficial feature of a conductor.
Electrical conductivity is the property of a substance that allows electricity to flow freely through it. It is inversely proportional to electrical resistance.
The dielectric strength of a substance refers to its ability to withstand high voltages. Thus, a material with a high dielectric strength may endure a sufficiently high voltage without degrading and conducting.
It is the rapid decrease in resistance of some metals at a temperature known as the superconducting transition temperature.
Magnetic characteristics of construction materials
Magnetic materials are those that can be induced into a state of magnetism. These materials generate a magnetic field in their immediate vicinity. Several significant magnetic qualities include the following:
- Forces of coercion
- Magnetic Hysteresis
The permeability of a material is defined as the ratio of its flux density to the magnetizing force that produces that flux density.
The coercive force is the magnetizing power required to totally eliminate magnetism in an electromagnetic environment.
Hysteresis is the property of a magnetic material that causes energy to be wasted when its magnetism is reversed.
Chemical characteristics of construction materials
When engineering materials come into touch with other substances, they are prone to react and degrade chemically. Corrosion resistance, chemical composition, and acidity or alkalinity are all important chemical characteristics.