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Bitumen Emulsion

Bitumen Emulsions

Bitumen Emulsions have being developed and exponentially increased sinned they were created in 1900. Estimated presently at 20% of the global bitumen use, bitumen emulsions are basically an O/W – Oil on Water solution – A dispersion of bitumen particles on water, stabilized with the addiction of surfactants – Surface active agents – or most commonly known as emulsifiers, that will permit the bitumen to de diluted in water.
They are primarily used for tack coats for use in between hot mix asphalt layers and prime coats for thin hot mix surfacing layers or a chip seal pavements.

Bitumen emulsions are divided into three categories:

  • 1- Anionic with negatively charged globules

  • 2- Cationic with positively charged globules

  • 3- Non-ionic with neutral globules.

  • The main grades for bitumen emulsions are classified as follows:

    • Bitumen Emulsions
    • Bitumen Emulsion is an area where technological progress is still being made to meet the requirements of pavement engineering. Anionic emulsions were first developed. They are currently less favored than the cationic emulsions, as cationic emulsions coat the aggregates more efficiently due to their positive load and have therefore better adhesion properties. Cationic Emulsion is both more favored and more widely used.

    Emulsified Bitumen usually consists of bitumen droplets suspended in water. This dispersion under normal circumstances would not take place, since everyone knows that oil and water don’t mix, but if an emulsifying agent is added to the water the asphalt will remain dispersed. Most emulsion are used for surface treatments. Emulsions enable much lower application temperatures to be used. Application temperatures range from 45°C to 70°C. This is much lower than the 150 to 190°C used for hot mix asphalt cements. The lower application temperatures will not damage the asphalt and are much safer for field personnel.

    In the production of bitumen emulsion, water is treated with an emulsifying agent and other chemicals and is pumped to a colloid mill along with bitumen. The colloid mill breaks the bitumen up into tiny droplets. The emulsifying agent migrates to the asphalt-water interface and keeps the droplets from coalescing. The emulsion is then pumped to a storage tank.

    Bitumen emulsions are complicated and good chemistry is required to reach target desired emulsion properties. Variables in emulsion production include the base bitumen and the type and amount of emulsifying agent. There are two basic classifications of emulsions globally usually used, anionic bitumen emulsions and cationic bitumen emulsions. The type (chemistry) of the emulsifying agent used, determines the designation. Emulsifying agents are the chemicals used to stabilize the emulsion and keep the “billions and billions” of bitumen drops separated from one another. These compounds are large organic molecules that have two distinct parts to them. These parts are called the “head” and “tail.” The “head” portion consists of a group of atoms that chemically have positive and negative charge areas. These two charged areas give rise to the head being called polar (as in poles of a magnet). Because of this polarity, and the nature of some of the atoms in this polar head, the head is soluble in water. The tail consists of a long chain organic group that is not soluble in water, but is soluble in other organic materials like oils (bitumen). Thus, an emulsifying agent is one molecule with both water-soluble and oil soluble portions. This unique characteristic gives the chemical its emulsifying ability.

    Anionic Emulsions

    The term anionic is derived from the migration of particles of bitumen under an electric field. The droplets migrate toward the anode (positive electrode), and hence the emulsion is called anionic. In an anionic emulsion, there are “billions and billions” of bitumen droplets with emulsifying agent at the water bitumen interface. The tail portion of the emulsifying agent aligns itself in the bitumen while the positive portion of the head floats around in the water leaving the rest of the head negatively charged and at the surface of the droplet. This imparts a negative charge to all the droplets. Since negatives repel each other, all the droplets repel each other and remain as distinct bitumen drops in suspension. A typical anionic emulsifying agent is shown below along with a diagram showing the orientation of the agent at the bitumen-water interface and the negative charge imparted to each drop.

    Typical Anionic Emulsifying Agent
    Typical-Anionic-Emulsifying-Agent.jpg
     Cationic Emulsions

    The term cationic is derived from the migration of particles of bitumen under an electric field also. The droplets migrate toward the cathode (negative electrode), and hence the emulsion is called cationic. The cationic emulsifying agent functions similarly to the anionic; the negative portion of the head floats around in the water leaving a positively charged head. This imparts a positive charge to all the droplets. Since positives repel each other, all the droplets repel each other and remain as distinct bitumen drops in suspension. A typical cationic emulsifying agent is shown below along with a diagram showing the orientation of the agent at the bitumen-water interface and the positive charge imparted to each drop.

    Typical Cationic Emulsifying Agent

    Typical-Cationic-Emulsifying-Agent.jpg

    Breaking Characteristics of Emulsions

    Emulsions exist for ease of application. After application the water to should evaporate and leave the asphalt cement. In a surface treatment, after emulsion and aggregate have been applied to the road surface, the emulsion should “break” leaving the asphalt cement holding the aggregate. At that point traffic may be allowed on the surface without loss of aggregate. The type of emulsion used has a large effect on the speed of the “break” of an emulsion.
    Almost all surfaces have a net negative charge. The strength or intensity of this negative charge may be different from material to material. Because of this phenomenon, anionic and cationic emulsions break in different ways.
    In an application of anionic emulsion, negatively charged drops of asphalt are applied to a negatively charged surface. All components repel each other. The only way the emulsion can break is through the loss of water by evaporation. As more and more water is lost through evaporation, the particles are forced closer and closer together until they can no longer be separated by a film of water. At this point droplets coalesce into larger and larger drops and ultimately a sheet of asphalt on the road. A depiction of the application is shown below:

    cationic-emulsion-application.jpg

    In an application of cationic emulsion, we are applying positively charged drops of bitumen to a negatively charged surface. The bitumen drops are immediately attracted to the surface and begin to break. The emulsion also loses water by evaporation. Thus the cationic emulsion has two breaking mechanisms at work and will break faster than a corresponding anionic emulsion. A depiction of the application is shown below:

    cationic-emulsion-application.jpg

    The object of a surface treatment is to seal the road from moisture intrusion and provide a new skid resistant surface, but be open to traffic as soon as possible and retain aggregate. Due to the chemistry of emulsions, they may react differently in specific weather and application conditions. If you have problems in any of these areas, the problem could be because of the weather, aggregate condition or emulsion used.

    In bitumen emulsions the basic bitumen has also been diluted in order to facilitate application. Hot bitumen, water and emulsifier are processed in a high-speed colloid mill that disperses the bitumen in the water. The emulsifier produces a system in which fine droplets of bitumen, of between 30% and 80% of the volume, are held in suspension. If they separate in storage, the emulsion can easily be restored by agitation.

    Bitumen emulsions have a low viscosity and can be workable at ambient temperatures, which makes them ideal for use in road pavements and surfacing. This application requires controlled breaking and setting. The emulsion must not break before they are laid on the road surface but, once in place, they should break quickly so that the road can be in service again without delay.

    TACK COAT:

    What is tack coat?

    Tack coat (also known as bond coat) is a light application of asphalt emulsion between hot mix asphalt layers designed to create a strong adhesive bond without slippage. Heavier applications may be used under porous layers or around patches where it also functions as a seal coat.

    Why use tack coat?

    Without tack coat the asphalt layers in a road way may separate which reduces the structural integrity of the road and may also allow water to penetrate the structure

    What type of emulsion should be used for tack coats?

    The type of emulsion used for tack coats varies from country to country. Normal practice in the USA is to use a slow-setting emulsion that is diluted with water before application. In many European countries cationic rapid setting or specially designated low viscosity medium setting emulsions are used, which are applied undiluted.

    PRIME COAT:

    Why use prime coat?

    Prime coats protect the integrity of the granular base during construction and help reduce dust. In the case of a base which is to be covered with a thin hot mix layer or a chip seal for a low volume roadway, priming ensures a good bond between the seal and the underlying surface which otherwise would have a tendency to delaminate.

    Why use asphalt emulsion prime?

    Compared to cut back asphalt primes, emulsion primes are environmentally friendlier.

    What type of emulsion is most suitable for emulsion prime?

    Slow-setting grades of asphalt emulsions (diluted with water before application) are suitable. With dense granular bases, or stabilized bases the surface may need to be broken up by scarifying before application, to ensure good penetration.

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Penetration Bitumen

Penetration Bitumen

Penetration Bitumen Grade is a standard bitumen usually used as a Paving Grade Bitumen essential for road construction and for the production of asphalt pavements with superior properties, and it’s very important once it bounds the aggregates and creates a unique cohesion and stability to the bituminous mix.

This grade of Bitumen is mainly used in the manufacture of hot mix asphalt for bases and wearing courses.

Penetration Grade Bitumen supplied by BITUMENA is petroleum grade bitumen, manufactured from fractional / vacuum distillation of crude oil. The Bitumen supplied by BITUMINA is produced from vacuum residue (short residue) feedstock.

Penetration Grade bitumens are specified by the penetration and softening point test. Designation is by penetration range only. The penetration grade bitumens have a thermoplastic property which causes the material to soften at high temperatures and to harden at lower temperatures. This unique temperature/viscosity relationship is important when determining the performance parameters such as the adhesion, rheology, durability and application temperatures of bitumen.

Global Leading Bitumen ( GLB co ) supplies all Penetration Graded Bitumen Grades in correspondence to ASTM D946-09 and EN 12591-2009, including:

ASTM D946-09 Grades:

  • Bitumen Penetration Grade 40-50

  • Bitumen Penetration Grade 60-70

  • Bitumen Penetration Grade 85-100

  • Bitumen Penetration Grade 120-150

  • Bitumen Penetration Grade 200-300

EN 12591-2009 Grades:

  • Bitumen Penetration Grade 20/30

  • Bitumen Penetration Grade 30/45

  • Bitumen Penetration Grade 35/50

  • Bitumen Penetration Grade 40/60

  • Bitumen Penetration Grade 50/70

  • Bitumen Penetration Grade 70/100

  • Bitumen Penetration Grade 100/150

  • Bitumen Penetration Grade 160/220

Iran penetration bitumen (Iran bitumen 40/50; Iran bitumen 60/70; Iran bitumen 80/100; Iran bitumen 85/100) has high quality in the world.  It is famous to NIOC Iran bitumen and available in different grades, packing between 10000 MT to 12000 MT monthly.
Available packing is new steel drum, polybag, Bulk bitumen, Bitutank.

Product Summary

Global Leading Bitumen ( GLB co ) is member of syndicate Iranian bitumen exporter (Iran bitumen 40/50; Iran bitumen 60/70; Iran bitumen 80/100)  and partner of most drumming factories which has owned export license for exporting all grades of bitumen as per of ASTM standard such as :
Iran Bitumen 30/40, Iran Bitumen 40/50, Iran Bitumen 60/70, iran Bitumen 80/100, Iran Bitumen 85/100.

Penetration Bitumen?

Iran Bitumen is produced from selected crude oils through a process of fractional distillation. The crude oil is heated to temperatures of between 300 and 350 degrees Celsius and fed into a distillation column allowing the lightest fractions of the crude to separate, through vaporization, from the heavier fractions, which remain liquid.

The higher boiling point fractions are then drawn – off via a heat exchange and enter a vacuum distillation column. This process produces a “short residue” that is used to manufacture several grades of Iran bitumen.  The  pressure and temperature conditions  within  the vacuum  process  will  determine the hardness of the short residue, and as  such  the  grade  of  Iran bitumen produced.

The short residue may be further modified by   ‘air blowing’ in which air is passed through the residue at temperatures of 250 – 300 degrees Celsius.
The above are the typical Penetration or Paving Grades of bitumen. Additional processing provides other grades of bitumen products such as:

Oxidized bitumen – produced by more vigorous air blowing; they are more ‘rubber like’ and less temperature susceptible than the paving grades.
Hard Grade bitumen – harder paving grades.

Cutback bitumen – blends of penetration bitumen with solvent such as kerosene.
Emulsions – stabilized suspensions of bitumen in water.
Polymer Modified Bitumen – mixtures of selected bitumen with polymers such as thermoplastics or elastomers.

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Cutback Bitumen

What is Bitumen (Asphalt) Cutback Bitumen?

Bitumen is ‘cutback’ by adding controlled amounts of petroleum distillates such as kerosene. This is done to reduce the viscosity of the bitumen temporarily so it can penetrate pavements more effectively or to allow spraying at temperatures that are too cold for successful sprayed sealing with neat bitumen. The materials used to cutback bitumen will evaporate after application to leave the remaining material similar in hardness to the original bitumen.

Applications of Cutback Bitumen in Bituminous (asphalt) Pavement Construction and Maintenance:

Prime and Tack Coating

The process of priming involves applying a low viscosity binder to a prepared but usually unbound aggregate base. It is intended to be absorbed by the top layers of the base and provide a surface more easily ‘wetted’ by a subsequent bituminous covering. The primer will be able to carry traffic for a short time (although this practice is uncommon) and help control dust. Generally, primers are applied at rates between 0.5 and 1.4 L/m2. Cutback bitumens suitable for priming are also used for tack coats, which are applied to an underlying surface to help with the adhesion of subsequent asphalt layer. A typical application rate is between 0.2 and 0.4 L/m2.

Prime Sealing

Where temperatures are too cool for an effective priming operation, or where traffic is likely to upset a primed surface before the final seal can be sprayed, a primer seal can be used to give adequate protection of the pavement for periods of up to 6 to 12 months. Cutback bitumens suitable for primer sealing can also be used in the manufacture of pre-mix asphalt, which is used in patch repairs.

Spray Sealing

Cutback bitumens are used extensively in sprayed sealing applications, particularly in cooler weather where they provide improved initial stone retention due to their lower viscosity. Typically, a single application of the appropriate cutback bitumen is sprayed onto the primed pavement onto which aggregate is laid

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Oxidized Bitumen

Oxidized Bitumen

Oxidized bitumen is blown asphalt which is exporting in various grades as Oxidized Bitumen 115/15,Blown bitumen 90/40,75/25, 85/25, 90/15, 105/35, 150/5 95/25 and any other grade will produce according to order.

United petrol is a dynamic and multi-faceted limited company actively involved in manufacturing procurement distribution and export of various grades of oxidized bitumen. We are structured into focused on oxidization of Bitumen division to serve the different needs of our customers worldwide.

We have a long history of supplying Oxidized Bitumen to bitumen factories, asphalt companies, roof insulation companies and membrane sheet manufacturer

Throughout the world, more than 7 types of bitumen that is produced depend on the type of weather conditions one of them is Oxidized Bitumen or blown bitumen

Oxidized bitumen grades are suitable for sealing saw cuts and joints where there is expected to be the minimum amount of moving in the joint. Their wide temperature range prevents bleeding in high temperature applications. Oxidized bitumen can also be used in industrial applications like roofing, flooring, mastics, pipe coatings, electrical applicatin.

Oxidized Bitumen

What is Oxidized Bitumen?

Bitumen used in a wide variety of ‘industrial’ applications including roofing, flooring, pipe-coating etc. They are produced by passing air through soft bitumen/flux mixtures under controlled temperature conditions. British Standard grades (BS 3690) are normally designated by two numbers representing the mid-points of their softening point and penetration ranges.

 How to produce Oxidized Bitumen (Blown Bitumen)?

 Production process:

  1. Bitumen heating to 265-270 °C
  2. Transferring melted bitumen to blowing towers
  3. Blowing air to bitumen
  4. Cooling melted bitumen with water
  5. Packing

The procedures of producing bitumen are as follows:

  1. Continuous blowing procedure
  2. Discontinuous blowing procedure

These two procedures are done by other two procedures named catalysis and anticatalysis .

Catalysis means adding some chemical material during the process In order to decrease blowing reaction time.

For the following reasons:

¨ Ease and simplicity in changing blowing condition and have production with different grades as a result.

¨ Ease in generating the unit.

¨ Ease in technology and also low expense in investment.

The discontinuous producing procedure is chosen.

Technical point and operating conditions are as follows:

¨ The blowing should be done from the bottom of blowing tanker. The reaction between bitumen and air is calorific .If the heat produced during the mixture is high, the heat of reaction is controlled by water injection.

¨ Admixture of air and the volume of blowing air is two important variants in blowing process.  In bitumen producing plant, bitumen 60/70 is usually got by blowing. In this case for making bitumen 90/15 or 85/25 distilled used oil or crude oil should be injected to the product according to the volume 20-25 % otherwise the fragility in bitumen lead to inferior production.

¨ Increasing the heating temperature, air injection amount, time and tower pressure increase the speed of production process reaction. The suitable temperature for production operation is 265-270°C which should be controlled not to be ascended since in high temperature and in 288°C  intensity of reaction becomes more sever and incontrollable which lead to explosion in tower.

¨ The long time stay of bitumen in tower in any condition is not in favor of system and should be delivered to drum or empty tanker after being ready.

¨ If the liquid surface in blowing tower is low, not more than particular limit should be added to the system for the extra air gather in empty parts and lead to ignition nearly. And if the temperature is kept high, the inside heat of tower ascend fats and this issue cause inside explosion and endamage the system.

¨ Blowing tower is filled up to 70%. Air injection is done in 190-232°C. The final point of blowing is specified by sampling and testing of bitumen properties. Finally the temperature of product should be kept 150- 165 °C in order to have loading and packing capability.

The production process is as follows:

The producing operation of oxidized bitumen mainly includes tank loading different steps, bitumen blowing, condenser external gases and packing. So in the beginning the loose bitumen shipped to the plant by tanker is transferred to the raw material store tanker. In order to transfer the bitumen easily to the blowing tower the burner is contrived at the bottom of the store tanker to heat them. It is necessary to say that if the blowing towers are empty, hot bitumen can be uploaded directly to them and blowing operation start.

Since the volume of bitumen increases as a result of blowing and it may overflow, the blowing tower is filled up to 70 %.

Air injection is usually done when the temperature of material reach to 190-230 °C.

For gradual heating and also pipes filling with the air is entered from the top of the tower and at the bottom the bitumen dispread monotonously in phase via nozzel then oxidation is done accordingly and the light molecule, volatile gases and steam are emitted from the top of the tower.

Blowing operation is done in temperature range 215-290°C but the suitable temperature is between 265 to 270°C. The needed heat is provided by burner contrived at the bottom of the tower. The bitumen reaction is calorific so in order to prevent the explosion danger resulted from temperature increasing, the temperature can be controlled by water injection, burner extinguisher and air amount reducing.

Blowing end point is usually signified by sampling from tower and bitumen properties testing. The blowing operation stops when oxidized bitumen reaches to specified properties. After this in order to fix the final point and depolymerization bitumen got in high temperature. It is necessary to be transferred to store after packing and presented to sale.

It is necessary to say that the produced gas and steam entered the condansor through the pipe fixed at the top of the blowing tower. In this stage the bad smelling gases and oily and volatile parts are separated from then transfer to sewage accompanied with water. Other unseparated  gas  parts is emitted from top of the condenser then transfer to furnace and burned there. After cooling the blowing oven and reaching them to 150-160°C, all the content of blowing oven which is hard bitumen is able to be loaded and packed. Because of the liquid height in blowing tower, oxidized bitumen is transferred by specific gravity and there is no need to use pump. Packing is done in two sections and in 220 liter drum and 35 kg carton. For fast operation (preventing from cooling & hardening) in every section several taps are fixed so that it can fill specific drum and carton with bitumen in same time.

Oxidized bitumen (oxidsed asphalt) products

Oxidized bitumen 85/25 (blown asphalt)

Oxidized bitumen 90/15 (blown asphalt)

Oxidized bitumen 90/40 (blown asphalt)

Oxidized bitumen 95/25 (blown asphalt)

Oxidized bitumen 115/15 (blown asphalt)

Oxidized bitumen 150/5 (blown asphalt)