Sunday, December 16, 2018

 

Bonyan Novin Shimi Pars (BNSP) Co.

Asphalt and Bitumen Additives

 

Bitumen in different forms is used as a binder in road construction. At ambient temperature, bitumen is an extremely high viscous liquid that is not workable. It can be transferred into a workable state in three ways:

• by heating

• by blending with petroleum solvents (cutback)

• by emulsifying in water to form bitumen emulsion

Bitumen emulsions provide an alternative approach in which the bitumen is liquefied by dispersing in water.

An emulsion can be defined as a dispersion of small droplets of one liquid in another liquid. Bitumen emulsions are an oil-in-water type of emulsion where the bitumen is dispersed in water. The size of the droplets is generally in the range 1 to 50 micron.

To obtain a stable bitumen emulsion, an emulsifier has to be added. The bitumen droplets are kept apart due to the effect of the ionized emulsifier molecules, and a stable emulsion will be produced.

Depending on emulsion types and their applications, two main types of emulsifiers (Cationic and Anionic) are produced in BNSP Company.

 

1-      Cationic Emulsifiers:

In a cationic emulsion the positivelycharged ions orientate themselves to the surface of the bitumen droplets.

 

Rapid-Setting emulsions:

Be used for tack coat, chipseal and penetration macadam with 0.15 to 0.25 % wt. (1.5-2.5 kg per ton of emulsion)  of emulsifier. BNSP recommend the following emulsifiers for this application:

 

Neftamin-55

Neftamin-66

 

Medium-setting emulsions:

set less quickly and be used for cold mix asphalt, and surface dressing with 0.4 to 0.6 %wt. (4-6 kg per ton of emulsion) of emulsifier. BNSP recommend the following emulsifiers for this application:

 

Neftamin-55

Neftamin-66

 

Slow-setting emulsions:

be used for prime coat, mulch, and micro surfacing with 0.8 to 1.2 %wt. (8-12 kg per ton of emulsion) emulsifier. BNSP recommend the following emulsifiers for this application:

 

Neftamin-1357

Neftamin-1976

 

2-      Anionic Emulsifiers:

In ananionic emulsion the negatively charged ions orientate themselves to the surface of the bitumen droplets.An anionic emulsion does not break chemically. The water evaporates and causes the emulsion to break. Because this is a much slower process, these emulsions are used especially for recycling asphalt and slurry seal with 0.5 to 2 %wt (3-5 kg per ton of emulsion) emulsifier.BNSP recommend the following emulsifiers for this application:

 

NX-5500

NX-6000

 

3-      Anti-Stripping Agent:

The fact that roadways can suffer water damage is well established. The symptoms of water damage are  various  and  include  rutting  and  shoving,  loss  of  chippings  from  surface dressings  (chip  seal), raveling  of  surface  layers  leading  to  potholes,  susceptibility  to  freeze-thaw  damage,  cracking  and bleeding. But the underlying problem on a micro scale is loss of adhesion between the binder and the aggregate.

Bitumens, especially those of high acid value, have a tendency to become negatively charged and thus adhesion problems occur particularly, but not exclusively, with acidic aggregates.

All road materials can be damaged by water.  Experience has shown that there are few aggregates which completely resist the action of water under all conditions. The water may enter the pavement structure in several ways.

The  chemical  affinity  between  bitumen  and  aggregate  can  be  improved  by  the  addition  of  small quantities  of  chemicals  which  change  the  nature  of  the  aggregate  surface  or  the  nature  of  the bitumen. These chemicals are known as "adhesion promoters" or “Anti-stripping Agent”. The use of Anti-stripping  Agent  cannot  eliminate  all  the  moisture  damage  caused  by  poor  design,  bad construction techniques or poor materials, but it can reduce their effect in practice.

Bonyan  Novin  Shimi  Pars  Company  presents  a  qualitative  Liquid  Anti-stripping  Agents (Tackamin-180 and Tackamin-200)  that  is  manufactured  implementing  latest production  techniques.  Used  as  an  adhesion  promoter,  Bitumen  Anti-stripping  Agent  helps  in reducing  the  damage  made  to  Bituminous  Pavements  with moisture  and  rain.  The Anti-Stripping Agent offered by us is tested by some professional companies in Iran and producing excellent results. In addition to this, we provide availability of Liquid Anti-stripping Agent in high quantity suiting to the preferences of customers.  Anti-Stripping Agent can be obtained at cost-effective prices of the industry.

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