Goldbitumen, a trusted manufacturer of premium bitumen from Iran, follows controlled refining methods to produce stable and reliable grades. Because the bitumen oxidation process plays a key role in determining the hardness, durability, and long-term behavior of the binder, it is essential for engineers and buyers to understand how it works. When oxidation happens correctly, the material becomes stronger and more suitable for industrial uses. However, when it occurs unintentionally during storage or heating, it can damage the binder and reduce performance. Therefore, learning how oxidation affects bitumen helps you make better selection and storage decisions.

What Is the Bitumen Oxidation Process?

The bitumen oxidation process is a chemical reaction where oxygen interacts with the hydrocarbons in bitumen. This reaction increases molecular weight, changes viscosity, and makes the material harder. Although oxidation happens naturally over time, refineries often use a controlled method called air blowing to produce oxidized or blown bitumen.

In simple terms:
➡ Bitumen + Oxygen + Heat → Harder and more durable bitumen

Because oxidation changes the structure of bitumen, it directly affects its behavior in roofing, waterproofing, and insulation applications.

How Oxidation Changes Bitumen Properties

During the bitumen oxidation process, several important changes occur:

• Viscosity increases

• Penetration value decreases

• Softening point increases

• Elasticity decreases

• Resistance to flow improves

• Temperature stability rises

As a result, oxidized bitumen becomes better for applications that require heat resistance and long-term durability, such as:

• membrane manufacturing

• roofing sheets

• pipe coating

• electrical insulation

• industrial adhesives

Therefore, oxidation allows manufacturers to tune the binder for specific industrial uses.

Why Refineries Use the Bitumen Oxidation Process

Refineries intentionally oxidize bitumen to meet international standards for specific grades, including:

• Bitumen 85/25

• Bitumen 95/25

• Bitumen 90/40

• Bitumen 115/15

• Bitumen 105/35

These grades must have a higher softening point and lower penetration for industrial performance. Because natural penetration bitumen cannot reach these levels, refineries rely on controlled oxidation.

The Controlled Air-Blowing Method

The most common industrial method is air blowing, where hot air passes through vacuum bottom feedstock.

Step-by-Step Process:

1. Vacuum bottom is heated to around 250–300°C.

2. A steady flow of air is blown through the bitumen.

3. Oxygen reacts with the binder, increasing molecular weight.

4. The bitumen gradually becomes harder and more stable.

5. The process stops when the desired grade is reached.

Because the bitumen oxidation process must be predictable, temperature and air flow are closely monitored.

Chemical Reactions During Bitumen Oxidation

Although the process looks simple, the chemistry behind it is complex. Several reactions occur:

• Oxidation: hydrocarbon molecules react with oxygen

• Polymerization: molecules join together to form larger chains

• Dehydrogenation: hydrogen atoms are removed

• Condensation: molecules combine to create harder structures

Together, these reactions increase the bitumen’s hardness and its resistance to heat and deformation.

Benefits of the Bitumen Oxidation Process

Because oxidized bitumen behaves differently from penetration bitumen, it offers several advantages:

• stronger resistance to aging

• higher softening point

• reduced flow at high temperatures

• improved stability in membrane production

• better bonding in adhesives and mastics

• longer service life

• greater waterproofing performance

Consequently, oxidized bitumen is preferred for industrial and roofing applications where natural bitumen fails.

Difference Between Oxidized Bitumen and Penetration Bitumen

Although both are bitumen types, they behave very differently.

Because oxidized bitumen resists flow even at high temperatures, it is ideal for industrial sectors that require heat stability.

Uncontrolled Oxidation: The Hidden Danger

While controlled oxidation is beneficial, uncontrolled oxidation is harmful. This is the oxidation that happens:

• inside storage tanks

• during long-term heating

• when exposed to air for too long

• during repeated reheating cycles

Uncontrolled oxidation causes:

• hardening

• cracking

• brittleness

• loss of elasticity

• early failure

Therefore, understanding the bitumen oxidation process helps you avoid accidental hardening during storage.

How to Reduce Unwanted Oxidation During Storage

To prevent harmful oxidation and maintain quality:

• store bitumen at the correct temperature

• avoid keeping it hot for long periods

• prevent air exposure inside tanks

• use nitrogen blanketing when possible

• keep drums sealed tightly

• avoid repeated heating cycles

These steps keep the material stable and extend its lifespan.

How Goldbitumen Ensures Controlled and Safe Oxidation

Goldbitumen uses advanced refining systems to guarantee:

• consistent oxidation temperature

• controlled air flow

• perfectly matched softening point

• stable penetration values

• clean, impurity-free feedstock

• accurate ASTM test results

Because of these strict controls, buyers receive oxidized bitumen that performs predictably and reliably.

Conclusion: The Bitumen Oxidation Process Shapes Industrial Performance

In summary, the bitumen oxidation process plays a major role in determining hardness, heat resistance, and long-term stability. While controlled oxidation creates high-quality industrial-grade bitumen, uncontrolled oxidation can cause damage and reduce performance. Therefore, choosing a reliable supplier like Goldbitumen ensures you receive stable, properly oxidized bitumen that meets demanding industrial requirements.