Construction Materials Research Paper

TASK 1(P1):

• Describe the property of construction materials.

1) Chemical resistance: - The ability of material to withstand with the action of acids, alkalis, gases and salt solutions is known as its chemical resistance. This property is carefully examined while selecting material for sewer pipes, hydraulic engineering installations, sanitary facilities, etc.

2) Bulk density:- The term bulk density is used to mean the mass of a unit volume of material in its natural state i.e. including pores and voids. It is obtained by finding out the ratio of mass of specimen to the volume of specimen in its natural state.

3) Coefficient of softening: - The ratio of compressive strength of material saturated to water to that in dry state is known as the

As there are practically no dense substances in nature, the density index of most of the building materials is less than unity.

5) Frost resistance: - The ability of a water saturated material to resist repeated freezing and thawing without considerable decrease of mechanical strength or visible signs of failure is known as the frost resistance. The frost resistance of a material depends upon the density of material and its degree of saturation with water.

6) Hygroscopicity: - The property of a material to absorb water vapors from air is known as the hygroscopicity and it is governed by the nature of substance involved number of pores, air temperature, relative humidity,

Some varieties of naturally occurring thermo plastic where known to Egyptians and Romans to extracted and use these plastics for various purposes. A number of scientists carried out experiments for plastics and as a result of long research, the birth of plastic industry took place in the 19th century. The last stage includes the present and its aim at improving the old plastics and producing new varieties of plastics. Such development is mainly responsible for two world wars during which extensive research is carried out of the plastics with the desire properties. The beginning of this stage was made by an Austrian scientist- Pollack. He prepared a substance from urea and formaldehyde in 1924. This substance was transparent like glass, but it was unbreakable. It was also possible to produce it in many attractive colors and shades. A strong revolution in plastic industry came during the period of Second World War (1939-1944). Within such a short period, the plastic has proved to be a very important engineering material. The plastics because of their wide acceptance as engineering materials are replacing the