What is Bitumen?

Bitumen

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Ans. Bitumen is a petroleum product obtained by the distillation of petroleum crude oil. Bitumen found in gaseous, liquid semisolid or solid form. Bitumen is hydrocarbon material of either natural of either natural of pyrogenous origin.Bitumen consider to be flexible from structural point of view.I is completely soluble in Carbon disulphide( CS2) and in carbon tetrachloride( CCl4).Bituminous materials are widely use in road construction and maintenance.

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Cutback Bitumen

Cutback bitumen is a type of bitumen which obtained from viscosity of bitumen is reduced by volatile diluent. It is generally used in colder region.

Types of cutback bitumen-

(i) Rapid Curing Cutback(RC)- In this bitumen is fluxed with naptha or gasoline.

(ii) Medium Curing Cutback(MC)- In this bitumen is fluxed with kerosene.

(iii) Slow Curing Cutback( SC)- In this bitumen is fluxed with high boiling point diluent.

Bitumen Emulsion

It is the condition in which bitumen is suspended in an aqueous medium.It is used for patch up work. Bitumen emulsion is generally used in rainy season.
Types of bitumen emulsion-
(i) Rapid Setting(RS)- It is used for surface painting.
(ii) Medium setting(MS)- It is used for premixing with coarse aggregate.
(iii) Slow Setting(SC)- It is suitable for fine aggregate mixes.

Penetration Test of Bitumen-

Hardness of bitumen is obtained by the penetration test.It is measured the distance a standard blunt point needle will vertically penetrate a sample of materials at 27 degree C , the load being 100g and time of application of load being 5 seconds. The unit of penetration is 1/10 mm. Thus 80/100 grade mean 8-10 mm penetration.Commonly used bitumen are 30/40 and 80/100 grade of bitumen depending upon construction type and climate conditions. Grade of bitumen is decided on the basis of penetration test. If the grade of bitumen is A-30 then it means this bitumen is manufactured from Assam petroleum and penetration value.

Ductility Test of Bitumen-

Ductility is measured as the distance in cm to which a standard briquette of size 10* 10 mm can be stretched before the thread breaks at a standard temperature of 27 degree C and the rte of elongation is 50 mm per minute.Bitumen should be sufficient ductile and capable of being stretched without breaking. Ductility is a measure of adhesiveness and elasticity of bitumen.Minimum ductility value according to ISI is 75 cm for grade 45 and above.

Spot Test of Bitumen-

This test is used to detect whether the bitumen is cracked or not. In this test 2 g of bitumen is dissolved in 10 ml of naptha. A drop of solvent is taken into filter paper.If the strain of the spot on paper is uniform in colour, the bitumen is accepted as uncracked bu if the spots from dark brown or black circle in the centre, the bitumen is consider to be over heated or cracked.

Flash and Fire point Test of Bitumen-

Flash point is the temperature at which bitumen vapours momentarily takes fire in the form of flash. Standard flash point according to Indian Standard Institute(ISI) is 175 degree C.

Fire point is the lowest temperature at which bitumen gets ignited and burn. Pensky-Martens closed cup are used for conducting the tests.The safe limit for heating bitumen is normally 50 degree C below the flash point.

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What is Bitumen? | Cutback Bitumen | Bitumen Emulsion | Penetration Test |.Ductility Test | Spot Test | Flash and Fire point Test