Construction material includes all materials used for civil construction work. eg, Stone, Brick, Cement, Wood, Paint, etc.
Stone:- Stone is a natural material obtained from the quarry.
a. Geographical Classification
|i. Igneous Rock||It is formed by the solidification of the molten mass of silicates below or surface of the earth. The main constituent is silica. Eg, Granite, Dolerite, Diorite, Syenite, Pegmatite, Basalt, Trap, Gabro, Obsidian, Pumice.|
|ii. Sedimentary Rock||It is formed by the deposition of debris, sand, silt, etc, which are subjected to the action of rain, wind sun i.e enormous overburden pressure for a million of years. The main constituents are sand, silt, detritus. Eg, Limestone, Sandstone, Conglomerate stone, Gypsum, Dolomite, Magnesite, Chalk, Shale, Kankar, Tripoli, Diatomite, etc. Also known as Aqueous Rock.|
|iii. Metamorphic Rock||It is formed due to a change in texture or mineral composition or both Igneous or Sedimentary rock due to high pressure and temperature. Eg, Gneiss, Quartzite, Marble, Slate, Schist, Serpentine ,etc.|
b. Physical Classification
|i. Stratified Rock||It can be split along distinct layers. Eg, Sedimentary Rock, Marble, Quartzite.|
|ii. Unstratified Rock||It can not split into a thin layer. Eg, Igneous Rock.|
|iii. Foliated Rock||It has a tendency to split in a certain direction. Eg, Metamorphic Rocks except for Marble and Quartzite.|
c. Chemical Classification
|i. Argillaceous rock||The main constituent is clay. Eg, Laterite, Slate.|
|ii. Silicious rock||The main constituent is silica. Eg, Quartzite, Basalt, Trap, Gneiss, Sand Stone, Granite, Syenite, Flint.|
|iii. Calcareous rock||The main constituent is lime. Eg, Lime Stone, Marble, Dolomite.|
a. Quarrying:- The process of taking out stone from a natural rock known as quarrying.
b. Quarry Sap:- The moisture content of stone during the period of quarry known as quarry sap.
c. Seasoning of Stone:- The removal of the sap of stone is called seasoning of stone.
d. Dressing:- Giving a definite, regular, and smooth face to the stone known as dressing.
a. Heavy stone suitable for retaining wall, dam, etc.
b. Soft stone suitable for ornamental work.
c. Light stone is suitable for Arches, Domes, etc.
d. In stone masonry, the stone should be placed such a way that the pressure acting on them is at angles to their natural bedding plane.
e. Limestone and Sandstone should not be used together.
f. Sandstone is a form of Quartz.
g. The minimum crushing strength of stone should be 100kg/cm2 whereas good building stone should be 1000kg/cm2 crushing strength.
h. Good quality building stone should not absorb water more than 5% of its weight and stone is rejected if it absorbs water more than 10% of its weight.
i. Strength of stone in wet condition is 30-40% less as compared to dry condition.
j. Good Building stone should be hard, tough, compact grade, and uniform in size and texture.
k. Moho Scale is used to find the hardness of stone material.
l. Moho Scale value increasing order…Talc(1)→Gypsum(2)→Calcite(3)→Fluorite(4)→Apatite(5)→Orthoclase(6)→Quartz(7)→Topaz(8)→Sapphire(9)
Testing of Stone:-
|1. Smith Test||To find dirty material in stone.|
|2. Brard Test||For frost resistance.|
|3. Acid Test||To check weather resistance.|
|4. Crushing Test||Strength of stone.|
|5. Absorption Test||Amount of water absorbed in 24 hrs.|
|6. Attrition Test||To check resistance to Abrasion.|
|7. Hardness Test||To Hardness of stone|
Properties of Material:-
|a. Cleavage||It is the tendency of minerals to split along a certain plane parallel to the crystal face.|
|b. Streak||It may be defined as the colour of its in powder form.|
|c. Colour||Colour is the main characteristic of minerals.|
|d. Luxture||It’s shine on the surface of a mineral and its appearance under reflected light.|
|e. Texture||It is the arrangement of the constituent mineral grains available in stone.|
Characteristics of Good Stone:-
|a) Appearance||For the face work, it should have fine, compact, texture, and light colour.|
|b) Easy of working||Property is found in soft stone but opposes to strength, durability and hardness.|
|c) Hardness||Important Property for flooring, apron or bridges, pavement.|
|d) Structure||The stone should be strong & durable to withstand the disintegrating action of the weather.|
|e) Weight||It indicates the stability of structures like dams, retaining walls.|
|f) Porosity and Absorption||It depends on minerals constituents, cooling time, and structural formation. More porous stones are not suitable for building work.|
|g) Toughness||It is a measure of the impact that stone can withstand.|