Definition of Oxidized Bitumen
Generally, Oxidized bitumen or Blown asphalt constitutes one of the foremost cheap film-forming materials to use in coating compositions and has found widespread use in various sorts of paints, cement, pipe coatings, metal primers, and similar compositions. Oxidized Bitumen is a type of bitumen that obtains from blowing air to pure bitumen. It has a lower penetration grade and more softening point in comparison to pure bitumen.
Based on its softening point and penetration grade it classifies into three types low, medium, and hard oxidized bitumen.
The performance of oxidized bitumen plays a crucial role in its successful application across various industries. This part aims to explore the key factors that influence the performance of oxidized bitumen and provides strategies to enhance its overall performance. By understanding these factors and implementing effective strategies, users can achieve superior performance and optimize the utilization of oxidized bitumen.
Blown Bitumen is manufactured by blowing air through bitumen. Specifically, in the air-blowing method of bitumen production, the air at 190 to 200 c is blown to the substance, and the oxidized or air-blown asphalt is produced. Among the unique specifications of Oxidized Bitumen are flexibility, increased durability, and resistance to water.
Oxidized Bitumen is a peculiar amorphous material that is generally in liquid form when discharged by oxidation plants at a temperature ranging from 240°-300°C., and becomes solid or pasty at ambient temperatures. While being relatively hot, it is vicious, whereas when in a pasty or solid-state it possesses a fair degree of elasticity. Both in liquid and in plastic or solid form blown bitumen is a highly insulating material with good adhesion properties with respect to almost any solid material.
Oxidized bitumen usage
Blown grade bitumen is widely used as an anti-slip layer compound in the piling industry, for the manufacture of roofing felts, for sound dampening felts, and undercarriage sealant in the automobile industry, electric cable joint protection, joint filling compound, sealant compound, and many others.
Blown asphalt is an aesthetic adhesive substrate for asphalt membranes. Metal and concrete protective coating under atmospheric conditions. Blown asphalt is used for coating pipelines. Blown asphalt is impregnated by a coating of papers and boards. Bonding agent for tiles and mastic also bonding agent for cork plates and adhesive for roofing felts.
Applications of oxidized bitumen in construction
1. Roofing Materials
- Bituminous Membranes: Oxidized bitumen is commonly used in roofing membranes, including bitumen roofing felt. These membranes offer excellent waterproofing and durability.
- Flat Roofs: Its resistance to UV rays and weathering makes it ideal for flat roofing applications where longevity and protection from the elements are crucial.
2. Waterproofing
- Basement Waterproofing: Oxidized bitumen is used in waterproofing systems for basements and foundations. It provides a reliable barrier against moisture infiltration.
- Concrete Protection: It can be applied to concrete structures to prevent water damage and deterioration.
3. Paving and Road Construction
- Asphalt Mixes: Though less common than standard bitumen, oxidized bitumen can be used in specific types of asphalt mixes to enhance performance in certain conditions.
- Repair and Maintenance: It’s also used in road repair and maintenance for its ability to adhere well to existing surfaces and provide a durable finish.
4. Industrial Applications
- Coatings: Oxidized bitumen is used in protective coatings for industrial structures. Its resistance to chemical and environmental factors makes it suitable for harsh conditions.
- Insulation: It can be used in various insulation applications, including thermal and acoustic insulation materials.
5. Waterproofing Membranes for Underground Construction
- Tunnel Linings: In underground construction, such as tunnels and underground facilities, oxidized bitumen membranes are used to provide waterproofing and protect against ground moisture.
6. Gaskets and Sealants
- Construction Sealants: Due to its flexibility and adhesive properties, oxidized bitumen is used in sealants and gaskets for joints and seams in construction projects.
7. Protective Layers for Infrastructure
- Bridges and Overpasses: It provides a protective layer for bridges and overpasses, helping to guard against environmental wear and tear.
Key Benefits:
- Durability: Increased resistance to aging and weathering compared to non-oxidized bitumen.
- Adhesion: Good adhesion properties make it effective in various construction applications.
- Waterproofing: Excellent water resistance makes it suitable for waterproofing tasks.
Properties of Oxidized Bitumen
- Increased Hardness
- Modification: Oxidized bitumen is produced by blowing air through heated bitumen, which increases its hardness and viscosity. This process also enhances its resistance to deformation under load.
- Temperature Stability
- Thermal Resistance: It has a higher softening point compared to non-oxidized bitumen, making it more stable in high-temperature environments. This property helps maintain its performance in hot climates.
- Reduced Elasticity
- Lower Flexibility: While this reduced elasticity can be a disadvantage in some applications, it is beneficial for specific uses where rigidity is preferred.
- Enhanced Durability
- Long-Term Stability: Oxidized bitumen exhibits improved resistance to aging, UV radiation, and weathering, which contributes to its long-term durability and lifespan.
- Chemical Resistance
- Resilience: It has better resistance to various chemicals, which can be advantageous in industrial applications where exposure to corrosive substances is common.
- Adhesion Properties
- Good Bonding: The material has excellent adhesive properties, allowing it to bond well to different surfaces and substrates.
Maintenance of Oxidized Bitumen
Maintaining oxidized bitumen is crucial for ensuring its longevity, optimal performance, and resistance to environmental factors. This article aims to provide practical and effective maintenance strategies for oxidized bitumen, emphasizing the importance of regular inspections, cleaning, repairs, and protective measures. By following these maintenance practices, users can maximize the lifespan and functionality of oxidized bitumen in various applications.
- Regular Inspections
- Cleaning and Debris Removal
- Handling and Transfer
- Storage and Containment
- Emergency Preparedness
Differences between oxidized bitumen and conventional bitumen
1. Production Process
- Conventional Bitumen:
- Production: Conventional bitumen is derived from the distillation of crude oil during the refining process. It is produced by heating crude oil to separate bitumen from other components.
- Characteristics: The bitumen produced in this way is typically softer and more flexible at room temperature.
- Oxidized Bitumen:
- Production: Oxidized bitumen is produced by blowing air through heated bitumen. This oxidation process increases the bitumen’s viscosity and hardness.
- Characteristics: The process results in a more rigid material with higher softening points and reduced elasticity.
2. Physical Properties
- Conventional Bitumen:
- Softening Point: Has a lower softening point, which means it becomes softer and more flexible at lower temperatures.
- Elasticity: More elastic and flexible, making it suitable for applications where movement and flexibility are required.
- Oxidized Bitumen:
- Softening Point: Has a higher softening point, which gives it greater stability in high-temperature environments.
- Elasticity: Less elastic and more rigid, providing greater resistance to deformation under load but less flexibility.
3. Performance Characteristics
- Conventional Bitumen:
- Temperature Sensitivity: Can become soft and lose strength in high temperatures, and may become brittle in cold conditions.
- Durability: Generally has lower resistance to aging, UV radiation, and weathering compared to oxidized bitumen.
- Oxidized Bitumen:
- Temperature Stability: Performs well under high temperatures and has a higher resistance to softening and deformation.
- Durability: Exhibits enhanced resistance to aging, UV radiation, and weathering, contributing to a longer service life.
4. Applications
- Conventional Bitumen:
- Road Construction: Commonly used in asphalt mixes for road paving due to its flexibility and ability to accommodate thermal expansion and contraction.
- Roofing: Used in roofing applications where flexibility and ease of application are needed.
- Oxidized Bitumen:
- Roofing Membranes: Ideal for flat roofing and waterproofing membranes due to its durability and resistance to weathering.
- Waterproofing: Utilized in basement waterproofing, concrete protection, and industrial coatings due to its superior waterproofing capabilities and chemical resistance.
- Industrial Uses: Applied in protective coatings and insulation where durability and resistance to harsh conditions are crucial.
5. Cost and Economic Considerations
- Conventional Bitumen:
- Cost: Generally less expensive due to the simpler production process.
- Maintenance: May require more frequent maintenance and replacement, leading to potentially higher long-term costs.
- Oxidized Bitumen:
- Cost: Often more expensive due to the additional processing involved.
- Maintenance: Longer-lasting and more durable, which can lead to cost savings over time through reduced maintenance and replacement needs.
Procedures for Production Oxidized Bitumen
The Vacuum bottom (VB) in liquid form by Blowing Bitumen with a petroleum distillate fraction is customary and is generally accomplished in tanks equipped with coils for air agitation or with a mechanical stirrer or a vortex mixer.
Air is heated up to 150–250°C and introduced at the bottom of a blowing production tower. It then migrates through the Bitumen to the top of the blowing production tower.
The chemical reactions result in bitumen with a different mixture of molecular structures. Catalysts can influence this process.
The production operation of producing Blown Bitumen mainly includes tank loading in different steps, Bitumen blowing, condenser external gases, and packing.
Air injection is usually done when the temperature of the material reaches 190-230 °C.
For gradual heating and also pipes filling with the air is entered from the top of the tower and at the bottom, the BITUMEN dispread monotonously in phase via nozzle then oxidation is done accordingly and the light molecule, volatile gases, and steam are emitted from the top of the tower.
Oxidized Bitumen Benefits
- Extended Lifespan
- Durability: Due to its resistance to weathering and aging, oxidized bitumen has a longer service life compared to non-oxidized bitumen. This can reduce the need for frequent replacements and maintenance.
- Improved Performance in Harsh Conditions
- Weather Resistance: Its stability in extreme temperatures and resistance to UV radiation make it suitable for use in challenging environmental conditions.
- Enhanced Waterproofing
- Effective Barrier: It provides excellent waterproofing capabilities, making it ideal for use in roofing membranes, basement waterproofing, and other moisture-resistant applications.
- Versatility
- Multiple Applications: Oxidized bitumen is used in a variety of construction and industrial applications, including roofing, waterproofing, paving, and protective coatings.
- Economic Efficiency
- Cost-Effective: Its durability and extended lifespan often result in cost savings over time, as it reduces the frequency of repairs and replacements.
- Ease of Application
- Workability: It can be easily applied and integrated into various construction systems, whether in the form of membranes, coatings, or sealants.
- Good Adhesion
- Bonding Strength: The strong adhesive properties ensure effective bonding with other materials, which is crucial for both construction and industrial uses.
Oxidized Bitumen Specification:
Among these bitumen, the most widely used oxidized or blown bitumen in the market is R85/25 that whose softening point is 85 and its penetration grade is 25.
Blown Asphalt 85/40 is popular in some European countries like Denmark, Norway, Finland, and Sweden.
The standard test methods used to obtain each property are as below:
- Specific Gravity: ASTM D70
- Penetration : ASTM D5
- Softening Point: ASTM D36
- Loss on heating: ASTM D6Flash point: ASTM D92
- Solubility: ASTM D4
- Ductility: ASTM D113
- Spot test: AASHTO 102
Product Benefits:
- Weatherproof packaging for flexibility of storage.
- High capacity, quality assured manufacture.
- Conforms to ASTM standards with regards to softening point and penetration.
- Wrapping can be melted in conventional boilers without the need for removal.
Health & Safety for Oxidized Bitumen
workers should comply with these tips:
- Ventilation: workers anywhere working should have appropriate Ventilation Because Blown Bitumen can release fumes when heated, which can be harmful if inhaled.
- Protective Equipment: workers should use heat-resistant gloves, safety shoes, long-sleeved shirts, long trousers, and safety goggles.
- Fire Safety: Workers work with high temperature for this reason Keep bitumen away from open flames or sparks and have appropriate fire extinguishing equipment on hand.
Oxidized Bitumen Packing:
Oxidized Bitumen has a different Packing and you can see some of these packings:
- Meltable Polyamide Bags in (20&25 Kg)
- Carton Box in (20,25&40 Kg)
- Kraft Bags in (20,25&40 Kg)
- Blocks in (20,25&40 Kg)
- Drums in (20&25 Kg)
