Emulsion Bitumen

An emulsion is a mixture of two immiscible liquids, one of which is dispersed in the other in the form of very fine particles. The process of emulsification is accomplished by use of an emulsifier and a stabilizer. Bitumen emulsions are dispersions of bitumen in water. Hot bitumen, water and emulsifier are processed in a high speed colloid mill that disperses the bitumen in the water in the form of small droplets. The emulsion making material is usually alkali salt of an organic acid or ammonium salt which charges bitumen particles.Emulsions which are made with negatively charged emulsifiers are called anionic emulsions while emulsions made with positively charged emulsifiers are called cationic emulsions.

Bitumen emulsions normally comprise between 30% and 80% bitumen by volume. Bitumen emulsions have a low viscosity compared to the bitumen from which they are produced and can be workable at ambient temperatures. Their application requires controlled breaking and setting. The emulsion must not break before it is laid on the road surface but, once in place, it should break quickly. When the emulsion is applied on the road it breaks down resulting in release of water and the mix starts to set. The time of setting depends upon the grade of bitumen.

Three types of bituminous emulsions are available, which are Rapid setting (RS), Medium setting (MS), and Slow setting (SC). Bitumen emulsions are ideal binders for hill road construction. Where heating of bitumen or aggregates are difficult. Rapid setting emulsions are used for surface dressing work. Medium setting emulsions are preferred for premix jobs and patch repairs work. Slow setting emulsions are preferred in rainy season.

The use of Emulsion bitumen is increasing for its advantages. All of the advantages of emulsions flow directly from this fact that Asphalt emulsions are dispersions of Asphalt in water and stabilized by a chemical system.

Asphalt emulsions are dispersions of Asphalt in water and stabilized by a chemical system. All of the advantages of emulsions flow directly from this fact. The main areas of advantage of emulsions are related to this can be summarized in terms of: energy conservation/ pollution control/ safety, versatility, ease of use, performance

Sources:fegrease.com, bp.com, petrotarco.com, cdeep.iitb.ac.in, highway1.co.nz, slurry.com

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Cutback Bitumen

Cutback asphalt is simply a combination of asphalt cement and petroleum solvent. Like emulsions, cutbacks are used because they reduce asphalt viscosity for lower temperature uses (tack coats, fog seals, slurry seals, stabilization material). Cutback bitumen is used for cold weather bituminous road construction and maintenance

Cutback bitumen in normal environment temperature is liquid, or is changed to liquid with a little heat. Similar to emulsified asphalts, after cutback asphalt is applied, the petroleum solvent evaporates leaving behind asphalt cement residue on the surface to which it was applied and the bitumen will bind the aggregate. Cutback asphalt is said to “cure” as the petroleum solvent evaporates away.

The speed of its clotting or hardening depends on the kind of liquid. For example because of high speed of gasoline evaporation, bitumen solved in gasoline hardens faster. The distillates used for preparation of cutback bitumen are naphtha, kerosene, diesel oil, and furnace oil.

Depending on the kind of solvent, there are different types of cutback bitumen, like rapid curing (RC), medium curing (MC), and slow curing (SC). RC is recommended for surface dressing and patchwork. MC is recommended for premix with less quantity of fine aggregates. SC is used for premix with appreciable quantity of fine aggregates.

The use of cutback asphalts is decreasing because of firstly environmental regulations. Cutback asphalts contain volatile chemicals that evaporate into the atmosphere. Emulsified asphalts evaporate water into the atmosphere. The second reason is due to high amount of energy and money required. The petroleum solvents used require higher amounts of energy to manufacture and are expensive compared to the water and emulsifying agents used in emulsified asphalts. In many places, cutback asphalt use is restricted to patching materials for use in cold weather.

Sources: cdeep.iitb.ac.in, pavementinteractive.org, petrotarco.com

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Asphalt in Road Construction

Asphalt in Road Construction

          
Majority of today's roads are constructed using asphalt but its use has been traced back even thousands of years. This naturally occurring substance is sought after for a number of applications due to its adhesive and waterproofing properties. Though the substance is so common today that it is not usually given a thought, asphalt is all around us in the form of roads, airport runways, roofs, tennis courts, parking lots, batteries, adhesives and more. Over ninety percent of the roads in the United States are constructed using this valuable, binding substance, but how did this come to be?

... Asphalt, blacktop, asphalt concrete, tarmac, bituminous concrete or macadam, can be naturally occurring but today is more commonly produced as a byproduct of the refining process in the petroleum industry.

P.S: Gildatar Bitumen and Asphalt is a company that provides excellent service to the civil contracting industry: bitumen sealing, asphalt surfacing of roads.
Author: Bob Jent

Oxidized Bitumen (Air Blown)

For the next several posts,I am going to introduce different types of bitumen.Blown Bitumen is the first and it will be followed by cut back, emulsion, modified  and fluxed bitumen . Hope to find the info helpful.

Oxidized Bitumen is produced by passing air through a bitumen feedstock under controlled conditions. This produces higher softening point bitumen with reduced susceptibility to change with temperature and greater resistance to imposed stresses. Compared with pure bitumen, blown bitumen has a low penetration rate and a high softness point.

The degree of oxidation can range from very small, often referred to as air-rectification, or semi-blowing, which only slightly modifies the bitumen properties, through to “full” blowing, whereby the properties of the bitumen are significantly different to penetration grade bitumen.

Oxidized Bitumen is produced by either Continuous or Staggered Blowing Process. The producing operation of oxidized bitumen mainly includes different steps: tank loading, bitumen blowing, condenser external gases and packing.

Blown grade bitumen is widely used as an anti-slip layer compound in the piling industry, for manufacture of roofing felts, for sound dampening felts and under carriage sealant in the automobile industry, electric cable joint protection, joint filling compound, sealant compound and many others

P.S: Gildatar is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Sources: e-asphalt.com , eurobitume.eu , petrotarco.com , benzeneinternational.com , blownbitumen.com

What is Bitumen?

To have a real start of the blog, I have prepared a post on the first basic question everyone unfamiliar with Bitumen will ask:"What is Bitumen?" here I have tried to present a fairly simple description of Bitumen! I hope you find it useful.

Bitumen is a dark black, greasy and viscous oiled based substance.  A non-crystalline viscous material having adhesive properties derived from petroleum either by natural or refinery processes and substantially soluble in carbon disulphide.

Bitumen is a mixture of Organic Liquids and composed primarily of highly condensed Polycyclic Aromatic Hydrocarbons. It would typically comprise at least 80% carbon and 15% hydrogen, the remainder being oxygen, sulphur, nitrogen and traces of various metals.

Bitumen can be obtained from various sources. It occurs naturally or from refinery process. Bitumen is found in nature in several forms, from the hard, easily crumbled bitumen in rock asphalt to the softer, more viscous material found in tar sands and so-called asphalt lakes.

Naturally occurring or crude bitumen is a sticky, tar-like form of petroleum which is so thick and heavy that it must be heated or diluted before it will flow. At room temperature, it is much like cold molasses.
Bitumen may occur naturally but for most purposes it is petroleum on which the world relies for its supplies of bitumen. Refined Bitumen is the residual (bottom) fraction obtained by fractional distillation of crude oil. It is the heaviest fraction and the one with the highest boiling point, boiling at 525 °C (977 °F). The bitumen content of crude petroleum oil can vary between 15% and 80%, but the more normal range is 25% to 40%.

In North America, bitumen is commonly known as “asphalt cement” or “asphalt”. While elsewhere, “asphalt” is the term used for a mixture of small stones, sand, filler and bitumen, which is used as a road paving material.  In Australian English, Bitumen is sometimes used as the generic term for road surfaces. In Canadian English, the word bitumen is used to refer to the vast Canadian deposits of extremely heavy crude oil, while asphalt is used for the oil refinery product used to pave roads and manufacture roof shingles.

The uses of bitumen are numerous. The chief one in most countries is for road construction. It is also used for surfacing airfield runways and taxi tracks, hydraulic applications such as canal lining, river bank protection, dam construction and sea defenses. There are also numerous industrial applications like roofing felt manufacture, printing inks, electrical cable / Junction boxes, mastic for roofing of terraces, duplex paper manufacture etc.

P.S: Gildatar Bitumen is proud to make possible the supply of Middle East bitumen in multiple grades 60/70, 80/100, 85/100, 85/25, 40/50, and 30/40.

Sources: petroleumbazaar.com , bp.com , shivamtarproducts.com , eurobitume.eu