BBitumen?!!

were used as cements to hold stonework together in boat building and as waterproofing in pools and baths.

Asphalts

The asphalt used by these ancient civilizations was formed when crude petroleum oils rose to the earth's surface and formed pools.

natural asphalt

The word bitumen comes from the original sanskrit word

Gwitumen

are bituminous condensates obtained in the process of destructive distillation of coal, petroleum, wood and other organic materials at high temperature without access of air.

Tars

on the other hand is a naturally occurring bitumen which is a combination of an inorganic mineral matter either calcareous or siliceous and an organic matter-a chemical compound of carbon and hydrogen.

Asphalt

isa non crystalline solid or viscous material derived from petroleum, by natural or refinery process and substantially soluble in carbon disulphide.

Bitumen

a yellowish oily substance, an excess of which makes bitumen to meltat low temperature

petrolene

hard black substance, an excess of which makes bitumen brittle and non-plastic. Its compositions is carbon 87 per cent, hydrogen 11 per cent and oxygen 2 per cent.

asphaltene

is a liquid product containing bitumen to a great extent in an aqueous medium.

Bitumen emulsion

is obtained by passing air under pressure at a higher temperature through the bitumen.

It can be used as roofing and damp-proofing felts, in the manufacture of pipe asphalts and joint fillers, as heat insulating material, etc

Blown bitumen

Is obtained by fluxing asphaltic bitumen in presence of some suitable liquid distillates of coal tar or petroleum.

It is mainly used in road construction and in soil stabilization (2-4%).

Cut-back bitumen

consists of bitumen, thinner anda suitable inert filler. The amount of inert filler is about 40 to 45 per cent. It is used for filling cracks in masonry structures, for stopping leakage, etc.

Plastic bitumen

is the bitumen being distilled toa definite viscosity or penetration without further treatment.

Straight run bitumen

Pure natural bitumen occurs rarely. Limestones, sandstones and soils impregnated with bitumen are frequently found.

Natural Bitumen

are product of processing crude petroleum and its resinous residues. These are classified as residual asphaltums, oxidized, cracked and extracted bitumens.

Petroleum Bitumens

are black or dark-brown solid substances at normal temperatures, obtained byatmospheric-vacuum distillation ofhigh-resin petroleum after topping of gasoline, kerosene and fractions.

Residual Asphaltums

are produced by blowing air through petroleum residues. Oxygen from air combines with hydrogen of the residues to give water vapour.

Oxidized Bitumen

are obtained by the cracking-high temperature decomposition-of petroleum and petroleum oils allowing high yield of gasoline. Blowing of air through residues gives oxidized cracked bitumens.

Cracked Bitumen

depends greatly on temperature. At lower temperature, bitumen has great viscosity and acquires the properties of a solid body, while with increase in temperature the viscosity of bitumen decreases and it passes into liquid state.

Viscosity

depends upon temperature, group composition and nature of structure. Viscous bitumens, containing solid paraffins at low temperatures are very ductile.

Ductility

is related to viscosity. Bitumen needs sufficient fluidity before specific application.

Softening Point

Bitumen is resilient, non-rigid and as such it is capable of absorbing shocks and accommodate itself to the movement in structure due to temperature, settlement or shrinkage.

Resilience

These are manufactured by running refined bitumen on to paper of different thicknesses and qualities. These sheets are used for damp proof courses.

Bituminous Sheets

When bitumen is used in hot applications, the process is known as hot mopping in which case a suitable flux is added.

Fluxed Bitumen

is essentially a softening process.

Fluxing

is usually a heavy oil added primarily to control the final setting hardness, but may also serve to reduce the temperature at which a hot applied bitumen becomes workable.

flux

is a natural or artificial mixture in which bitumen is associated with inert mineral matter. It is black or brownish black in colour.

Asphalt

is also known as native asphalt. When obtained from lakes it is termed as lake asphalt.

Natural Asphalt

is a naturally occurring rock formation, usually limestone or sandstone intimately impregnated throughout its mass with 6-14% bitumen.

Rock Asphalt

is obtained by heating pitch to drive off the water and to draw off the mineral matter by segregating the impurities.

Refined Asphalt

is manufactured by adding pulverized natural rock gradually to molten refined bitumen, agitating the mixture for about 5 hours (200-250°) and placing it into moulds for cooling.

Mastic Asphalt

is the viscous residue obtained by the distillation of asphaltic base crude oil to 425°C.

Liquid Asphalt

is derived by distillation of asphalt in a volatile solvent. It contains about 80 per cent asphalt and remainder the solvents.

Cut-back Asphalt

is the pitch residue obtained by evaporation of the volatile constituent of coal tar. It is formed of an admixture of coaltar, pitch, ground iron slag, sawdust, chalk, etc.

Artificial Asphalt

is prepared by oxidizing asphalt at a high temperature the lighter oils vapourize and are drawn off at their condensation temperature, leaving a residual materialaspaltic cement.

It is used for flooring and water proofing and in expansion joints in concrete.

Asphaltic Cement

are known to have a long life

Bituminous materials

Exposure to sunlight over a long period is known to affect bituminous material adversely, and the degree to which they are affected will depend upon the type of material used.

The Effect of Sunlight

Mastic asphalt and pitch mastic are not readily combustible and entail no increase in the fire hazard.

Resistance to Fire

Floors composed of bituminous materials are moderately noisy.

Noise

Furol viscosity test, Engler viscosity test, penetration test, or softening point test may be performed for the purpose.

Consistency Test

is conducted in Fural viscometer shown in Fig.18.1. It consists of a cylindrical vessel with a standard orifice at the bottom.

Viscometer Consistency Test

In this method the time taken for a 50 cc of the tar sample is divided by the time taken, in seconds, by an equal quantity of water.

Engler Specific Test

determines the hardness of the bituminous materials by measuring the depth in millimeter to which a standard needle penetrates vertically under specified conditions of load, time and temperature.

Penetration Test

is formed at the pointed end, with the diameter of the smaller base: 0.14 to 0.16 mm.

truncated cone

This test is done to determine temperature susceptibility of the bitumen.

Softening Point Test

Viscosity defined as inverse of fluidity defines the fluid property of bituminous material. It is measured by determining the time taken bya specified quantity of binder to flow from a cup through specified orifice ata given temperature.

Viscosity Test

is the lowest temperature at which the vapour of a substance can be ignited in air by a flame under specifled conditions of test.

Flash point

Fire point is the lowest temperature at which the material gets ignited and burns under specified conditions. The name of the test is ________.

Pensky-Marten test

The significance of the test is that the bitumen should contain just sufficient oil to impart consistency necessary for processing and blending.

Loss on Heat Test

In this test the quantities of the various volatile oils added to bitumens fluxing or for cutting-back are determined.

Distillation Test

In this test water-free petroleum distillate is added to the sample and heated.

Water Content Test

This test indicates the purity of bituminous binders by finding the quantity of bitumen in binder.

Solubility Test

This test is performed to find the presence of paraffin, naphthalene, benzene, etc. which produce greasy effect and fail to hold the aggregate.

Sulphonation Index Test

The test consists of stretching the bitumen binder (in the form of standard briquette shown in Fig. 18.7) at standard temperature of 27°C and ata standard rate of 5 cm per minute till the thread breaks.

Ductility Test

is defined as the ratio of the mass of a given volume of the substance to the mass of an equal volume of water at 27" ± 0.1°C. It can be determined by Pycnometer method or Balance method.

Specific gravity

It is also known as aggregate bitumen affinity test. From the point of view of behaviour of aggregate towards bituminous binders, aggregate are classified into hydrophilic (which lose bituminous coating in the presence of water) and hydrophobic (which retain its bituminous coating).

Adhesion Test