What is Bitumen? Everything about Bitumen Definition and Types

Bitumen is a black solid or a viscous liquid derived from crude oil. More than 85% of the world’s bitumen production is used for road construction, 10% is used in other constructions and 5% is used in a variety of other industries, including insulation.

Read the rest of this article to know more about bitumen.

What is Bitumen? Bitumen Meaning & Definition

Bitumen is a viscous substance that exists in a liquid to a semi-solid phase. It has a blackish-brown color.

It is generally composed of asphaltene resin and other petroleum compounds. 

Different compositions of bitumen result in different properties.

You can read the bitumen production process page to know more details about bitumen manufacturing.

Bitumen Meaning in Other Languages

A lot of people search for the meaning of "bitumen" in their own language, so here's a quick answer:

In Hindi (बिटुमेन का मतलब): Bitumen (बिटुमेन) is a thick, black, sticky substance made from crude oil. It's mainly used to build roads.

In Tamil (பிட்யூமன் பொருள்): Bitumen is a black, sticky material from petroleum, mainly used for making and repairing roads.

In Bengali (বিটুমিন অর্থ): Bitumen is a black, tar-like substance from crude oil, commonly used in road and roof construction.

In Telugu (బిటుమెన్ అర్థం): Bitumen is a thick, black material made from crude oil, mostly used for roads and waterproofing.

In Malayalam (ബിറ്റുമെൻ അർത്ഥം): Bitumen is a black, sticky substance from petroleum, used mainly for road construction.

Bitumen Chemical Formula

The chemical composition of bitumen is a complex mixture of organic compounds, mostly from the families of paraffinic, aromatic, and naphthenic hydrocarbons. In fact, bitumen is a mix of two types of components. The first type is a polar system made up of asphaltenes and resins. The second type is a non-polar system made up of saturated and aromatic chemicals (maltenes).

Generally, there is no unique bitumen chemical formula but It's mostly consists of carbon (85%), hydrogen (10%), nitrogen (0% to 2%), oxygen (0% to 2%), sulfur (0 to 9%), and small amounts of metals like vanadium, iron, and nickel.

Is bitumen a liquid or a solid?

Bitumen can be either, depending on temperature. At room temperature, it's usually a thick, semi-solid material. When heated, it becomes a viscous liquid.

Origin of Bitumen

Bitumen is found in nature and also can be extracted from crude oil.

1- Bitumen of Natural Origin

In a few places on Earth, bitumen forms naturally, in oil lakes and hills, mostly in Canada, Venezuela, and Oman, with smaller natural deposits also found in western Iran. This natural form, also called Gilsonite, contains more impurities like sulfur and heavy metals, which makes it more expensive to extract and use than refinery bitumen.

For the full story of how natural bitumen forms and where it's found around the world, see our complete guide: Where Does Bitumen Come From?

2. Crude Oil Distillation

Most bitumen used today comes from crude oil, not nature. A distillation tower separates crude oil into different products, and the heaviest leftover material, called vacuum bottom, becomes the base for bitumen.

Different processes on this vacuum bottom produce different types, like penetration bitumen or oxidized bitumen, mainly used in road construction. Read more about different types of bitumen used in road construction.

To become familiar with the way bitumen is created in nature, how it is extracted from oil, what its classifications are, and what uses it has, watch the below video:

What is the Difference Between Bitumen, Tar, and Asphalt?

In the United States, the words bitumen and asphalt are synonymous, but in general, asphalt means the composition of aggregates and bitumen, as a binder, that is used for road construction.

Bitumen is a hydrocarbon substance. It is found naturally or comes through refining processes from crude oil. 

Tar is also a dark hydrocarbon material. But the difference between tar and bitumen is in the origin of their production. The tar is obtained through a special distillation process from wood or coal. Coal-based tar is high in benzene, which is cancer-causing. 

Tar is mostly used in road construction. The tar wood has been used for thousands of years in northern Europe to waterproof boats, among other uses. Coal fiber and wood also have medicinal properties and are used to treat psoriasis and eradicate germs.

Read our article about “The difference between bitumen, tar, and asphalt”.

Types of Bitumen and Their Applications

Since different crude oils produce bitumen with different properties, refineries classify it into several types. Here's a quick look at each one:

• Gilsonite : natural, solid bitumen, mined rather than refined
• Penetration grade : the most common type for road construction, graded by hardness
• Viscosity grade (VG) : graded by viscosity instead of hardness, widely used in India
• Bitumen emulsion : bitumen mixed with water, used for spraying and tack coats
• Cutback bitumen : bitumen mixed with solvents, for cold-weather work
• Oxidized bitumen : air-blown bitumen, used for waterproofing and roofing
• Performance grade (PG) : graded by real-world temperature performance

For full specifications, grading tables, and how to choose the right type, see our complete guide: Bitumen Types and Grades.

Bitumen Tests

Bitumen quality tests are a criterion for diagnosing the quality and classification of bitumen in the industry. These tests are also taken to control the quality and guarantee of the bitumen load issued and imported in the ports of origin and destination.

According to SGS standard, bitumen tests in summary, include:

1- Penetration Test

The penetration test is used to measure the hardness and softness of bitumen. Penetration bitumen obtained from the refinery is classified based on this test. The degree of penetration of bitumen is directly related to its ductility and shows that asphalt has a higher loading capacity.

High penetration bitumen is suitable for cold climates and low penetration bitumen is suitable for hot climates.

To perform this test, a needle is penetrated into the bitumen surface with a load of 100 grams for 5 seconds. The degree of penetration is equal to the amount of needle penetrating. Its unit of measurement is 0.1mm.

To know more details, you can read the bitumen penetration test. 

2- Viscosity Test

Viscosity test is used to determine the adhesion of bitumen to asphalt aggregates. Bitumen must have an optimal viscosity value. This means that very viscous or very low viscosity bitumen are not suitable for road construction. In addition, viscosity is highly sensitive to temperature increase, and with increasing temperature, the amount of viscosity decreases as a result, its cohesion is lost. For this reason, viscosity is measured at temperatures of 60 °C and 135 °C. By measuring these two viscosity we can have sufficient information about the best temperature we should mix and compact bitumen with aggregates.

To measure the viscosity, by the viscometer apparatus, the time required to remove a certain amount of bitumen from the viscometer is measured and multiplied by the correction factor of the device. The number obtained is equal to the viscosity of the bitumen.

To know more details, you can read the bitumen viscosity test.

3- Softening Point Test

Bitumen as a combination of different hydrocarbon materials such as asphaltene and resin does not have a specific melting point. By heating the bitumen, it becomes soft and melts slowly. 

The temperature at bitumen starts to melt/softer is called the softening point. This point is important for engineers because it indicates at what temperature the bitumen loosens and its adhesive decreases.

The laboratory method of measuring the softening point is the ring and ball method.

To perform the test, the bitumen sample is taken in two brass rings. Two steel balls are placed on the bitumen samples. Then the assembly is placed in a water bath and heated.

The softening point is the temperature at which the steel ball coated with bitumen hits the bottom of the glass beaker.

To know more details, you can read the bitumen softening point test.

4- Ductility Test

As long as the bitumen has good ductility, it will be resistant to road traffic as well as expansion and contraction of bitumen due to temperature changes, and the possibility of asphalt cracking will decrease and asphalt life will increase.

To measure this property, bitumen is poured into a special mold and the mold is pulled from both sides at a constant speed of 5 cm per minute. The amount of bitumen stretched to the moment of rupture is reported as ductility. The longer the length, the greater the ductility.

To know more details, you can read the bitumen ductility test.

5- Specific Gravity Test 

Specific gravity is the ratio of the mass of bitumen to the mass of water, while both of which have the same volume. 

Each bitumen has a certain amount of specific gravity. As a result, this property is used to measure the amount of impurities in the bitumen. It is also used for calculations.

We use a pycnometer to measure this property. First, weigh the pycnometer, then fill it with bitumen and weigh it again. In the same way, fill the pycnometer with water and weigh it. We subtract the weight of the pycnometer from the readings of the pycnometer filled with water and bitumen. The ratio of bitumen weight to water weight is equal to the specific gravity of bitumen.

To know more details, you can read the bitumen specific gravity test.

6- Solubility in TCE

This test is performed to measure the purity of bitumen. This test detects non-oil impurities. For this purpose, 2 grams of bitumen is dissolved in 125 ml of trichloroethylene. The solution is weighed and then filtered through Whatman paper. Impurities are washed and dried and finally weighed. The percentage of impurities should not be more than 1% because it indicates the low quality of bitumen. High impurity in bitumen will have low adhesion strength.

Insoluble matter (%) = mass of insoluble materials / mass of bitumen sample

To know more details, you can read the bitumen solubility test.

7- Flash and Fire Point Test

There are also risks in transporting and storing flammable materials. As a result, it is more important to notice the flash and fire point of bitumen.

Heat causes liquid materials to evaporate. If the liquid is flammable, it will catch fire if there is an ignition source like a flame. 

Two devices are used to obtain the flash point and fire point:

• Pensky-martens
• Cleveland open cup tester

The procedure of the test is that bitumen is poured into the cup of the apparatus and then it is heated. 

During heating, the flame passes over the liquid surface and through the vapors once every 2 seconds. 

The temperature at which an instant flame appears on the surface of bitumen is called a flash point.

To obtain the fire point, heat is continued and the flame continues to pass over the surface of the liquid until an instant flame reappears on the liquid surface for a moment. 

Compared to the previous flame, this one lasts longer. Its temperature is reported as the fire point.

To know more details, you can read the bitumen flash and fire point test.

8- Loss on Heating Test

The amount of volatiles in the bitumen is measured by the loss on heating test. Volatiles are compounds that have a lower boiling point than water and evaporate at a lower temperature. 

The higher the percentage of volatile materials in the bitumen, the harder it becomes for the asphalt during the heating process and it loses its elasticity. A suitable bitumen binder should contain less than 1% volatiles.

To perform this test 50 g of bitumen sample is heated in the oven at 163 °C for 5 hours. After that, the bitumen sample is weighed.

The percentage of loss on heating is calculated as follows:

Loss on heating (%) = [(Initial weight – Final weight)/Initial weight]*100

To know more details, you can read the bitumen loss on heating test.

9- Spot Test of Bitumen

The spot test of bitumen is used to indicate that the bitumen is not damaged during the refinery’s overheating. 

In a refinery, if the heating was so high the cracking occurs in bitumen. Cracked bitumen is not sticky enough to hold aggregates together. Moreover, it can not tolerate the preheated process for road construction.

To perform the test 10 ml of a solvent is put in a flask containing 2 grams of bitumen sample. The solution is rotated and placed in boiling water until it is dissolved completely.

After it cools at room temperature, put a drop on filter paper.

If the trace of the drop is brown the test is negative. Inversely if the drop is brown with a black center the test is positive and the bitumen is damaged.

To know more details, you can read the bitumen spot test.

10- Drop in Penetration after Heating Test of Bitumen

Drop in penetration tests measure the hardness and volatile content of bitumen. 

When bitumen is heated for construction the volatile component evaporates and causes the material to harden. When bitumen has more volatile content, its hardness increases after heating.

To perform the drop in penetration after the heating test, apply the needle with a load of 100 grams for 5 seconds on the bitumen surface. Note the amount of penetration in 0.1 mm.

Then the bitumen sample is placed in the oven at 163 ͐degrees celsius for 5 hours.

After removing the sample, it is allowed to cool. In the next step, the penetration test is repeated.

Drop in penetration value (%) = 

[ difference between 2 amount of peneration/initial amount ] * 100

To know more details, you can read the bitumen drop in penetration test.

Bitumen Manufacturers

According to global statistics, China is the largest producer (and also consumer) of bitumen in recent years, with a production of 22 million tons per year, and the United States is in close competition with an annual production of nearly 21 million tons. Russia ranks third with a production of almost 7.8 million tons per year. Iran, India, and South Korea follow closely behind with annual production of about 5 million tons, 

It is important to mention that the most important exporters are South Korea, Iran, Singapore, Russia, Canada, and Germany respectively.

In the bitumen market, competition is easier for manufacturers and sellers than in other markets.

There are no major players in this market. The top 5 largest producers and marketers of bitumen are:

• Exxon Mobil Corporation
• Royal Dutch Shell Plc
• bp p.l.c.
• Nynas AB
• China Petroleum & Chemical Corporation (SINOPEC)

If you are interested in knowing more about bitumen manufacturers in the world, read “Top 6 Bitumen Manufacturers in the World”.

Annual Consumption of Bitumen

Bitumen consumption has been steadily increasing from the beginning of 2000 to 2020.

The most common industry in which bitumen is used is the road construction industry. Demand for bitumen is close to 100 million barrels per year, which is due to the expansion of:

• Communication roads and repair of old asphalt to increase their service life
• Construction has led to an increase in roofing
• Various industries and civil works such as dam construction around the world in which bitumen is used

The most influential factors that affect the global demand for bitumen each year are:

1. Economy
2. The government budget for the road
3. Natural disasters such as rapid landslides, floods, volcanoes, and so on.
4. An unplanned event like terrorism, accidents, or corona!

The largest consumer of bitumen in the world is Asia-Pacific, where its main consumptions are in China due to the expansion of environmentally friendly construction projects, and India due to the extensive road network improvement project. 

After Europe, in third place comes North America, whose main consumers are the United States, followed by Canada.

The lowest volume of bitumen is consumed in African countries.

The amount of bitumen consumption in 2020 was over 100 million cubic meters. This number could have been higher, but due to the coronavirus pandemic and quarantine, many development projects were stopped, especially in early 2020.

In 2021, with the spread of two waves of the COVID-19, the demand for bitumen decreased cross-sectionally. َAlthough due to the expansion of vaccination and the controlled situation the construction and industrial projects in the world gradually grew and the consumption of bitumen increased.

Consumption is expected to decrease to less than 4% from 2022 to 2026. This forecast is due to the reduction of road construction projects using bitumen. One of these projects is the production of environmentally friendly roads in China.

Effects of Bitumen on Health

There are always concerns about the use of chemicals and the risks associated with their harm to health or the environment.

Even though bitumen is not a highly toxic substance, safety precautions must be observed when using it, especially for workers who work with it continuously. They need to observe the following points:

• Wearing appropriate work clothes. Work clothes must have long sleeves and pants
• Use thermally insulated gloves
• Use vented goggles when working with liquids
• Use a face shield when working with corrosive and toxic substances. The use of vented goggles is also recommended for extra protection
• If they are exposed to toxic foam, it is necessary to use a mask

–Bitumen Health Effects Include:

• Heated bitumen vapors lead to coughing, a scratchy throat, headaches, skin rashes, fatigue, eye irritation, and lung problems

–Long-Term Side Effects Include:

Bitumen exposure can cause lung and stomach cancer, pigment changes in the skin, bronchitis, and emphysema. In addition, bitumen additives may cause damage to the liver, kidneys, and nervous system. 

When hot bitumen releases hydrogen sulfide gas into the air, suffocation and even death may occur.

Because bitumen is a highly flammable material, care must be taken to keep energy sources such as cigarette butts, flames, and’s away from work.

Impacts of Bitumen on the Environment

By heating bitumen in road construction, toxic vapors enter the atmosphere. Furthermore, The evaporation of bitumen occurs at air temperatures, especially in the summer. This results in air pollution.

Asphalt also reduces soil fertility. In fact, natural soil elements such as iron and calcium, which are essential for plant growth, are reduced. To solve this problem and increase productivity, chemical fertilizers with safe concentrations can be used.

It is also better to use environmentally friendly packaging in the transportation of bitumen. Because by transporting thousands of barrels of New Steel drum, a large amount of waste enters the environment. Which has high recycling and reuse costs. It is better to use compatible packages such as jumbo bags.

Bitumen Price

The price of bitumen depends on several factors. The main factor in changing the bitumen price is the price of crude oil and the amount of supply and demand in the market.

In early 2020, oil prices and, of course, bitumen prices plummeted due to the coronavirus epidemic and quarantine conditions, as construction and industrial projects stalled and demand decreased.

In 2021, the price of bitumen fell cross-sectionally due to two Corona variants, Delta and Omicron. If world conditions are stable, in 2022 prices are expected to rise with a slight slope.

In the Middle East, the main suppliers of bitumen are Iran, Iraq, and, Bahrain. Factors affecting the price of bitumen in the Middle East are:

• World oil prices
• Regional prices of sulfur fuel oil
• The amount of demand from consuming countries, especially India
• Exchange rate of the Rial against the dollar
• Prices of global competitors such as Singapore, South Korea, Thailand, Italy, Greece
• Political conflicts, especially political conflicts in the Persian Gulf area in the Middle East
• Corona condition and its direct impact on demand and project progress
• Shipping cost
• Local competition between refineries

The above factors can also affect the global bitumen price.

[single_chart_module title="Bitumen Price Chart 2023-2024 (New Steel Drum) " id="28227"]

Storage, Packaging and Shipping Conditions

Bitumen has many packages depending on whether it is solid or liquid. These packages include:

• New steel drum
• Jumbo bag
• Bulk bitumen
• Flexitank

Bitumen is a flammable viscous material; so its packaging is very important considering the factors like cost, environment, storage, and shipping.

Drum packaging is the most common packaging because it is available in different sizes, has higher security, and is easy to transfer.

 It varies depending on bitumen volume, height, thickness, and lid. Although new steel drums are preferred to bulk trade, they are still more expensive compared to jumbo bags (steel is more expensive than plastic).

You can read more details on the “Bitumen Packages” page.

Bitumen Expiry Date

Bitumen expiry date depends on the type and grade of bitumen.

The properties of pure bitumen like penetration grade (Pen grade), viscosity grade (VG grade) and performance grades (PG grade) in storage for a long time will not be changed. Generally the stability of these grades of bitumen is high.

But for liquid bitumen like bitumen emulsion or cut back bitumen, the properties can be changed in the storage. The penetration bitumen, viscosity bitumen and performance bitumen have a long shelf-life, 3 to 15 years, but bitumen emulsion and cut back shelf-life is approximately 6 months.