Viscosity Grade Bitumen (VG Bitumen)

Viscosity bitumen is graded based on viscosity at 60°C and 135°C. In this type of bitumen, penetration at 25 °C is also measured. These properties help us to understand how bitumen responds to temperature fluctuations. Viscosity at 60 °C shows bitumen’s resistance to flow in hot climate conditions. On the other hand viscosity at 135 °C determines the behavior of bitumen while its temperature is very high for preparing hot mix asphalt. Penetration at 25 °C measures consistency at room temperature. Unlike the penetration test, which is an empirical method, the viscosity test of bitumen provides a more fundamental approach to analyzing bitumen’s behavior in a specific range of temperatures. The highest consumption of VG bitumen is in India. Viscosity bitumen has four different grades that are VG10, VG20, VG30, and VG40.

Asphalt Cement Bitumen (AC Bitumen)

AC grade, or asphalt cement bitumen, is a viscosity-based grade of bitumen, defined by the American Association of State Highway Officials (AASHTO). AC bitumen is categorized based on its average dynamic viscosity at 60 °C, divided by 100. For example, AC10 bitumen has a viscosity range of 800-1200 Poise. They are demanded in some markets like Sudan, Ghana, Cameroon, Djibouti, South Africa, Guinea, and Zimbabwe. Its main specifications are: penetration at 25°C, viscosity at two temperatures of 60°C and 135°C.

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AH Bitumen

AH bitumen is a popular bitumen type in the China market. They are graded based on penetration value at 25°C, like penetration grades. However, they have some differences in their tests and specifications. In contrast to the penetration grading system, viscosity at 60 °C is also measured in AH bitumen. The temperature of 60 °C corresponds to the highest pavement temperature during hot summer when rutting problems occur. Therefore, knowing the viscosity of bitumen at this temperature helps to better control one of the main problems of pavement distress. Another difference is the testing of AH bitumen’s ductility at both 10 and 15 °C. At 15 °C, AH bitumen has a ductility of over 100 cm, while penetration bitumen reaches the same ductility at 25°C. This indicates that AH bitumen can maintain its flexibility well even in cold weather. The most widely used grade of AH bitumen is AH 70, also referred to as bitumen 60/80, due to its ideal penetration range of 60 to 80 dmm.

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Oxidized Bitumen

Oxidized or blown bitumen is a bitumen type produced by blowing air into the pure bitumen.This process is done at high temperatures to modify its physical properties for specific uses. The process of blowing air causes oxidation and polymerization, resulting in larger molecular weight molecules that form a harder and less temperature-sensitive product. As the asphaltene percentage increases, oxidized bitumen has a lower penetration value and a greater softening point than pure bitumen.

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Performance Grade Bitumen (PG Bitumen)

PG bitumen is classified based on its ability to handle different temperatures and maintain desired properties. Compared to traditional grading methods such as penetration and viscosity, PG bitumen focuses on the overall performance of the bitumen rather than its physical properties. Performance grade bitumen is named with two numbers that show its performance ranges. For example, PG 76-16 indicates it’s resistant to temperatures as high as 76°C and as low as -16°C. PG bitumen is evaluated using various rheological and aging tests. The Dynamic Shear Rheometer (DSR) measures its resistance to deformation, while the Pressurized Aging Vessel (PAV) simulates long-term aging. Additionally, Direct Tension (DT) tests determine its flexibility and resistance to cracking under repeated load applications. These tests provide detailed information about long-term performance under varying stress and temperature conditions.

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Cutback Bitumen

Cutback is a type of liquid bitumen that is produced by blending penetration grade bitumen with a petroleum solvent such as gasoline, kerosene, and diesel. The percentage of solvent is varied from 20 to 45%.The main uses of them are in producing cold mix asphalt and sealing applications. Curing time is defined as the speed of solvent evaporation and remaining bitumen. Cutback bitumen has different curing times, as follows: • Slow Curing (SC): Produced using heavy petroleum solvents, such as diesel or mazut • Medium Curing (MC): Produced using semi-heavy petroleum solvents, such as kerosene • Rapid Curing (RC): Produced using light petroleum solvents, such as gasoline Cutback bitumen is classified based on curing time and viscosity.

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Petroleum & Petrochemical

Zem Team, core areas of expertise include:
• Petroleum Products: Such as bitumen, diesel, fuel oil, and lubricants.
• Petrochemical Products: Including caustic soda, caustic acid, polyethylene, and other chemical derivatives.

Steel and Metals

Zem Team, core areas of expertise include:

• Steel and Metals: Offering a wide range of products, such as steel billets, rebar, and alloy metals, tailored to meet the needs of various construction and industrial sectors.

Agricultural Commodities

Zem Team, core areas of expertise include:

• Agricultural Commodities: Such as grains, pulses, and high-quality cereals to support the growing demands of the global food supply chain.

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Zem Africa is a highly esteemed trading company with over two decades of extensive experience in global trade. We specialize in the import and export of a wide array of premium products, catering to diverse industries and markets.

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Over 20 years of excellence in the trade of petroleum, petrochemical, steel, and agricultural products

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Active and fully equipped offices in Dubai, Addis Ababa, and Djibouti enable us to manage operations seamlessly.

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Over 20 years of excellence in the trade of petroleum, petrochemical, steel, and agricultural products ...

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Active and fully equipped offices in Dubai, Addis Ababa, and Djibouti enable us to manage operations seamlessly ...

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At Zem Africa, we are more than just a trading firm—we are a bridge connecting markets, industries, and opportunities. Let us help you grow your business with confidence and consistency.

Steel and Metals

steel billets, rebar, and alloy metals, tailored to meet the needs of various construction and industrial sectors

Petrochemical Products

caustic soda, caustic acid, polyethylene, and other chemical derivatives

Agricultural Commodities

grains, pulses, and high-quality cereals to support the growing demands of the global food supply chain

Petroleum Products

bitumen, diesel, fuel oil, and lubricants large grains

STEEL AND METALS

Steel is a highly durable, hard substance. It’s manufactured by adding 2% carbon to pure iron. Due to its solidity and high tensile strength, steel is used for the fabrication of everything from oil tankers to sewing needles, as well as the tools used to produce them.

Steel is often combined with other metal types to incorporate different qualities. The combination used depends on the intended use. To cater to industrial demands, more than 75% of steel variations in the market were developed in the last two decades. Steel comes in thousands of different variations. The type you choose depends on what you intend to use it for.

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Penetration Grade Bitumen

Penetration bitumen is the most commonly used type of bitumen in road construction. It is categorized into several grades based on a penetration test that measures bitumen hardness at 25°C.