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The Advantages of Asphalt Emulsions for Road Construction

Asphalt Emulsions

Asphalt Emulsions. Asphalt is a standard in automobile road construction and repairs. Its application has a limitation: the viscosity of asphalt must be minimized. This can be achieved by one of the three different approaches:

  • heating;
  • mixing with petroleum based thinners;
  • emulsification.

The first method found its use in production of hot mix with preheating of mineral materials. There are both advantages and disadvantages. The former are the production of strong asphalt concrete, required for road repair and construction, from highly viscous asphalt. The latter are the energy cost to heat the mineral material in production of hot mixes, limited time for application of the road layers as well as environmental concerns.

The method is quite costly due to the high price of thinners. Besides, their evaporation contaminates the environment, and poses a fire hazard.

Asphalt emulsions, on the other hand, require no heating. This material can be used with moist and cold mineral materials, reducing power consumption by 30-40% compared to technologies which require heating of the binder.

Among other advantages of asphalt emulsion are:

  • the viscosity of asphalt emulsion at room temperature is significantly lower than that of asphalt. This allows emulsion to permeate even small pores and cracks;
  • bitumen emulsion is highly adhesive to various surfaces, including metals, as well as acidic or basic minerals. This allows for strong and durable road construction;
  • operation is possible at relatively low temperatures and high humidity due to increased adhesion of the emulsion to the treated surface. Strangely enough, moisture on the surface of the mineral materials plays a certain positive role;
  • increased precision of binder material dosage and even distribution in even thinner layers due to low viscosity for material economy;
  • fuel economy, since the mineral materials do not require heating. The process ensures the required quality in normal conditions, reducing the amount of energy consumption;
  • reduced emissions into the environment.

Asphalt emulsion are currently coming into wider use, pushing hot bitumen from the stage. In the general case, the use of asphalt emulsions improves road quality, increases labor efficiency; besides, emulsion can be used in cases where hot asphalt is inefficient.

One of the priority directions of GlobeCore is the design and production of the modern UVB-1 asphalt emulsion plants.

The GlobeCore asphalt emulsion plants feature the following advantages:

  • emulsion product fully meets ASTM D 2397-98 and D977-98 standards;
  • improved safety (emergency stop and safety interlocks);
  • dilution of blended chemicals with water inside the unit;
  • capability to make all types of emulsions, such as CRS, CMS and CSS-1,2, as well as anionic emulsion of the corresponding types, including sub-type h;
  • production of high quality asphalt emulsion regardless of initial asphalt quality by adding plasticizers, adhesion modifiers and thinners;
  • compact size;
  • simple operation and servicing.

Bitumen Storage and Heating Tanks

Bitumen Storage

Bitumen Storage. Bitumen is supplied to asphalt plants in special heated tanks. Special horizontal or vertical tanks are used for storage of bitumen, with volume range from 50 to 200 tons.

The number and volume of tanks is chosen depending on the consumption of the binder, and the frequency of supplies. Heating systems are built into the tanks to prevent heat loss and to keep bitumen temperature high enough. heating systems can also heat pumps, mixers and piping.

Heating of bitumen is important. If the correct temperature is not maintained, bitumen physical properties and chemical composition will change, making it impossible to obtain a quality asphalt mix.

Bitumen can be heated directly or indirectly. In the first case, the material is heated through thin wall heat tubes by hot gases, which result from the combustion of gas or liquid fuel. This method allows to rapidly heat the binder to the required temperature. The main drawback is that bitumen crust may form on the tubes.

Electrical heaters significantly simplify the heat exchanger design by eliminating the need for an intermediary heating substance. The limitations of such systems is less than gentle heating and also the formation of crust.

GlobeCore GmbH is one of the world leaders in industrial manufacturing. Products of GlobeCore are used in transformer oil purification and degassing, insulation oil filtration, power transformer vacuuming.

The head office is located in Oldenburg, Germany. Our systems have been supplied to and are successfully operated in 70 countries. A network of 17 dealers supports global sales and services.

GlobeCore established representative offices in United States, and South Africa and in United Arab Emirates to extend reach and improve efficiency. We actively expand production and sales territories, develop our infrastructure and introduce new additional services.

GlobeCore today is a large and diverse company. Over 260 specialists are working as a team from metal cutting to final assembly of the products.

The production facility is equipped in compliance with international industry standards: it features robotic plasma metal cutters, automated welding systems and modern PLC controlled machinery.

The engineering staff systematically develops new oil purification equipment and improves existing product lines. GlobeCore produces hundreds of units annually and each product is thoroughly tested at the company’s testing facility.

Bitumen Pumps

Bitumen Pumps

Bitumen pumps transport bitumen through pipelines and are widely used in asphalt plants.

At this time, external gear pumps are mostly used due to their reliability, as well as simplicity in operation and servicing. Besides, such pumps are successfully used for pumping of bitumen from storage tanks to portioning tanks of bitumen emulsion production plants.

When choosing a bitumen pump, it should be noted that its capacity must correspond to the capacity of the dosage equipment; the pump must meet the requirements to tank unloading and loading of bitumen sprayers and bitumen transportation trucks.

A bitumen pump consists of a black steel body and two cylindrical gears. To prevent bitumen from solidification in the pump, the pump is heated by steam supplied to the heating jacket of the pump. If steam heating is not possible, other methods are available, including electrical heating. Bitumen pump drives include gearboxes, couplings and motors.

Depending on mobility, the pumps can be mobile or stationary. In the former case, the pump is installed on a special cart and is driven by an internal combustion engine, while in the latter case it is installed on a concrete foundation and can be driven by any motor.

GlobeCore GmbH is one of the world leaders in industrial manufacturing. Products of GlobeCore are used in transformer oil purification and degassing, insulation oil filtration, power transformer vacuuming.

The head office is located in Oldenburg, Germany. Our systems have been supplied to and are successfully operated in 70 countries. A network of 17 dealers supports global sales and services.

GlobeCore established representative offices in United States, and South Africa and in United Arab Emirates to extend reach and improve efficiency. We actively expand production and sales territories, develop our infrastructure and introduce new additional services.

GlobeCore today is a large and diverse company. Over 260 specialists are working as a team from metal cutting to final assembly of the products.

The production facility is equipped in compliance with international industry standards: it features robotic plasma metal cutters, automated welding systems and modern PLC controlled machinery.

The engineering staff systematically develops new oil purification equipment and improves existing product lines. GlobeCore produces hundreds of units annually and each product is thoroughly tested at the company’s testing facility.

Running Bitumen Emulsion Equipment

On 30 June 2014, GlobeCore employees traveled to European country

and conducted a successful launch and commissioning of GlobeCore model UVB-1 intended for the production of bitumen emulsion.

Bitumen emulsion equipment manufactured and supplied by GlobeCore, is increasingly in demand.  This is the result of a wide spread acceptance of and demand for the cold process mix in preparation for the pavement, repair, and construction of roadways.

If you are a company engaged in road repair, road construction, building and structure construction, or production of asphalt mixes, the bitumen emulsion equipment from the Globecore is just what you need!

The GlobeCore UVB- 1 does not emit harmful gases into the atmosphere. Modification of the model with different capacities allow you to select the most suitable model for your specific conditions.  A climate version of the UVB-1 produces bitumen emulsion almost all year round from early spring to late autumn, without stopping earlier programmed processes.

New Road Construction Materials

In today’s road construction industry, great importance is placed on road surface durability.  It is generally accepted that it is impossible to improve road pavement durability without the application of new organic binding materials.  These materials would include bitumen emulsions, modified bitumen and cold technologies used with the application of such materials.

Modern cold application technology adoption is realized in several ways such as:

  • Production of gravel-emulsion mixtures;
  • Re-use of old asphalt-concrete with emulsion and composite binders;
  • Road surface waterproofing;
  • Production and application of cold mixtures for pothole repair; and
  • Membrane technologies for cement-concrete pavement repairs.

Bitumen is being emulsified to obtain emulsion with a definite set of physicochemical properties.  The final product therfore, is required to meet the following requirements:

  • to be resistant to storage and transportation; and
  • to properly coagulate after the mineral materials are applied on the surface.

The rate of emulsion breakdown is determined by (1) its composition, (2) the size of bitumen particles, and (3) the nature and granulometric composition of the mineral material.

GlobeCore has developed and produced equipment designed for bitumen emulsion production as well as polymer modified bitumen when using the UVB-1 and UVB-2 units.

The final product produced with GlobeCore eqipment fully complies with and exceeds international requirements and standards.

Skid Mounted Bitumen Modification Unit

The asphalt based road systems can no longer ensure the durability of the wearing surface because of  the increased  amount of heavy load carrying vehicles on our roads.  In the not so distant past, this problem could be solved by using crushed aggregates of average size or stone mastic asphalt.
The rapid development of motor vehicles has made the road builders take more effective measures to make the road surface more resistant to (1) high temperature extremes; (2) cracking at low temperatures; (3) surface scaling; (4) potholing; and (5) aging.

It has been known that the quality of a bitumen-concrete mixture is largely determined by the quality of the bitumen binders.

It was therefore, the researchers and road builders that decided that it would be reasonable to substitute polymer modified bitumen for traditional bitumen.  This tendency first appeared in the 1960s.  Since then, there has been an intensive, but, unsystematic development of modified bitumen.
The use of different polymers and a constant search for new ways to connect them with bitumen were the main tendencies of this development.  A clear theory of bitumen modification first appeared only at the end of the 20th century.

The theory states that the most effective modifiers are thermo-elastoplast polymers and that the substitution of  modified bitumen for traditional bitumen will benefit the service life of road surface pavement materials.

The fact that the standards for modified bitumen have been developed and consistently implemented in the European Union (EU) (2005) supports the long-term benefits of using modified binders.  GlobeCore GmbH has developed skid mounted bitumen modification units, designated as UBV-2, to produce high quality modified bitumen.  These units are made of separate standard blocks that can be replaced or added to meet the individual customer’s order and needs.  It helps to find a solution to any technological problems.

Fig.1. The main unit for modified bitumen production

The main unit for modified bitumen production (Fig.1) consists of:
(1) colloid mill; (2) premixing container for “SBS”(styrene-butadiene-styrene) and bitumen; (3) bitumen supply pump; (4) screw-type feeder of “SBS”; (5) tank-receiver for “SBS” with mounted load cells, and (6) a control systems.


Fig.2. Block of plasticizer and adhesive additive supply

Fig.3. Block of bulk materials input

All of these units are mounted in spatial relays that allows them to be transported  by any means of transport.  Additionally, these units can be completed with a “Block of plasticizer and adhesive additive supply” (Fig. 2) and (or) “Block of bulk materials input ” (Fig. (3).

“The block of plasticizer and adhesive additive supply” is an autonomous unit consisting of 3 pumping points: (1) bitumen; (2) plasticizer (3) adhesive additive; (4) an injector mixer; (5) a heat-transfer device; (6) a piping system; and (7) a control system.

“The block of bulk materials input” is also an autonomous unit consisting of: (1) a colloid mill; (2) an input bulk materials unit; (3) bitumen supply pump; (4) screw-type feeder; (5) tank-receiver of bulk materials with mounted load cells; and (6) a control system.

The blocks, described above, can operate independently as well as as a part of a set (Fig.4).

Fig.4. Skid Mounted Bitumen Modification Unit

This set may also be equipped with (1) modified bitumen storage tanks with volume of 15 and 30 m³; (2) container-type storage tank with volume of 32 m³; (4)  an oil heat generator with capacity of 70-500 kW (kilowatt) that operates on any kind of fuel or electricity.

The set may be equipped with pumping stations, designed to input and output of modified bitumen to meet the customer’s order.

All the units have reverse bitumen pipes that allow the operators to rinse equipment with clean bitumen when the main works are done.  Modular design of this equipment allows a quick mounting and dismounting when moving to another site.

Bitumen Emulsion Technology

In the road construction industry, bitumen serves as a binding material.  At ambient temperatures howver, it is very viscous and cannot be used as intended without heating.

In today’s modern road construction industry, there are three ways to make bitumen suitable for road construction projects:

  • To warm up bitumen to between 100º and 200°C;
  • To blend it with solvents (asphalt paint); or
  • To make bitumen emulsion.

Bitumen emulsion is a material where small particles of bitumen are distributed in a water phase (bitumen in water dispersion).  Such emulsions may be made of bitumen of different viscosity depending on the required performance characteristics of the final product.  According to the chemical nature of the surface-active substances, bitumen emulsions are divided into groups such as:

  • Anionic; and
  • Cationic.

There are three classes of  bitumen emulsions depending on the blending stability:

  • Quick-breaking;
  • Medium-breaking; and
  • Slow-breaking.

It should be borne in mind that cationic and anionic emulsions should not be blended together since their charges are equalized and emulsion separates into bitumen and water.  The bitumen emulsion storage tanks should be cleaned thoroughly before filling them with a different kind of bitumen emulsion.

The physicochemical performance characteristics of bitumen emulsion and dispersion degree are determined by the properties and amount of bitumen, emulsifier, and acid. 

Specialists consider that it is the emulsifier that determines the quality of bitumen emulsion.  There are a lot of chemical compounds that can be used to emulsify bitumen.  But, only some substances have found practical use because of rigid technical and economic regulations.

In recent times, cationic bitumen emulsions have become preferable since they are more unique and make binding material adhesive when reacting with the acid materials and other natural elements.  As compared to hot bitumen, bitumen emulsions have a wide spectrum of benefits that include:

  • Significant bitumen savings (up to 30-50%);
  • Energy conservation (up to 25-40%) since there is no need to warm up bitumen emulsion before application;
  • Compatibility with wet solid material;
  • Good adhesion of bitumen to roadbed;
  • Fire safety; and
  • Eco-friendliness.

Bitumen emulsion production is realized by the use of a colloid mill.  The quality of  the final product depends on the following parameters of the colloid mill:

  • Air-gap distance between the rotor and the stator (may be adjustable or constant);
  • Rotor speed. This parameter depends on dimensions and power of the mill; and
  • Design of the mill.

GlobeCore has designed its UBV-1 units to produce bitumen emulsions. Their capacity may vary from several hundreds of kilograms (laboratory units) to several tens of tons per hour (plant models).

GlobeCore
bitumen emulsion units allow for production of high-quality bitumen emulsions.

The GlobeCore UVB-1 bitumen emulsion units have gained widespread acceptance in many parts of the world.   Bitumen emulsions, produced by GlobeCore equipment, can be applied to carry out a wide spectrum of road construction projects such as:

  • Tack coating;
  • Ground stabilization;
  • Crush-stone grouting;
  • Sludge compaction;
  • Dust laying;
  • Minor road works;
  • Cold recycling;
  • Pothole repair;
  • Production of cold bitumen-concrete mixtures, paving type Slurry; and
  • Coarse surface treatment, paving type Chip Seal.