BITUMEN Ashalt, bitumen and tar are referred as bituminous materials, which are essentially hydrocarbon materials.The asphalt is a mixture of inert mineral matter lime alumina, lime, silica etc. and a hydrocarbon known as asphaltic bitumen. In some places like Trinidad and Bermudez, asphalt is available in nature at a depth of 3 to 60 metres. It is known as natural asphalt. Common variety used all over the world is residual asphalt, which is obtained by fractional distillation of crude petroleum oil. Bitumen is the binding material which is present in asphalt. It is a hydrocarbon. It is obtained by partial distillation of crude oil. It contains 87 per cent carbon, 11 per cent hydrogen and 2 per cent oxygen.Tar is obtained in the distructive distillation of coal, wood or other organic materials. When coal or wood is heated to redness in an closed chamber, it yields volatile product and residue coke. After separating and coo...
ASBESTOS Asbestos is a general name for several varieties of fibrous minerals which are available in nature. But presently, most of the commercial asbestos produced is ‘chriotile’ [Mg6SiO11(OH)6.H2O]. Properties of Asbestos 1. It is flexible, soft and non-porous. 2. It is fireproof and acid proof material. 3. It is a good insulator of heat and electricity. 4. When it is mixed with cement and water, it retains shape firmly. 5. Its colour is brown or grey. 6. It can be cut into pieces or can be drilled. 7. It possesses high tensile strength in the direction of its fibres. 8. Its specific gravity is 3.10. Uses of Asbestos 1. Asbestos cement sheets are the cheapest roofing materials. 2. Asbestos cement pipes are used as down take pipes of rain water from the roof. 3. With bitumen it forms good damp proof layer. 4. It is used for preparing fire proof ropes and clothes. 5. It is used as covering material for fuse and electric switch boxes. 6. It is...
Cube crushing machine Tests on Concretehe following are some of the important tests conducted on concrete: 1. Slump test. 2. Compaction factor test. 3. Crushing strength test 1. Slump Test: This test is conducted to determine the workability of concrete. It needs a slump cone for test Slump cone is a vessel in the shape of a frustum of a cone with diameter at bottom 200mm and 50mm at top and 300 mm high. This cone is kept over a impervious platform and is filled with concrete in four layers. Each layer is tamped with a 16 mm pointed rod for 25 times. After filling completely the cone is gently pulled up. The decrease in the height of the concrete is called slump. Higher the slump, more workable is the concrete. 2. Compaction Factor Test: This is another test to identify the workability of concrete. This test is conducted in the laboratory. The test equipment consists of two hoppers and a cylinder fixed to a stand, the dimension...
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