Crumb Rubber Modified Bitumen (CRMB) is a unique and innovative material that has gained significant attention in the road construction industry. This sustainable solution is made by blending bitumen with crumb rubber obtained from scrap tires, which results in a durable and flexible material with excellent resistance to wear, tear, and weather conditions. This page will explore the different aspects of CRMB, including its product description, history, types, forms, applications, properties, advantages, production methods, specifications, safety tips, importing and exporting countries, packaging, transportation, and storage.

Crumb Rubber Modified Bitumen (CRMB) is a high-quality road construction material made by adding finely ground rubber particles to bitumen. The rubber particles are obtained from scrap tires that are first shredded into small pieces and then further processed to remove any impurities. The resulting crumb rubber is then blended with bitumen in a specific ratio to produce CRMB. This material is typically black in color, with a soft and sticky consistency. It has excellent elasticity, which allows it to withstand traffic loads and temperature changes without cracking or deforming.

Petro Naft manufactures the highest quality Crumb Rubber Modified Bitumen (CRMB) in different types and grades and exports them from Iran and the UAE to other countries around the world.

Iran Crumb Rubber Modified Bitumen ( Iran CRMB)
UAE Crumb Rubber Modified Bitumen (UAE CRMB)


CRMB is a modified bitumen material that combines the benefits of bitumen and rubber to produce a durable and flexible road construction material. It is a sustainable solution that recycles waste tires and reduces the environmental impact of road construction activities. CRMB can be used as a binder in asphalt concrete, which is the most common type of pavement used on roads and highways worldwide. It improves the performance of asphalt concrete by increasing its resistance to deformation, cracking, and aging.


The use of rubber in road construction dates back to the early 1900s when Henry Ford used rubberized asphalt to pave his automobile factory’s parking lot. However, the commercial use of rubberized asphalt did not become widespread until the 1960s when the first rubber-modified asphalt was produced in the United States. Since then, the use of crumb rubber in road construction has become increasingly popular, especially in countries with large quantities of scrap tires.


CRMB is also known as rubberized asphalt, rubberized bitumen, rubberized asphalt concrete, and asphalt-rubber.


Crumb Rubber Modified Bitumen (CRMB) presents a sustainable, high-performance choice for a variety of applications within the paving industry. This innovative road construction material blends scrap tires, also known as crumb rubber, with traditional bitumen, creating an enhanced binder with improved properties.

The components of CRMB chiefly consist of two main elements:

  1. Crumb Rubber: Derived from waste tires that are mechanically ground into small particles, typically between 0.6 to 0.8 mm. This recycling process not only reduces landfill waste but also harnesses the physical properties of rubber for enhancing the overall characteristics of bitumen.

  2. Bitumen: A highly viscous, sticky substance that’s a byproduct of petroleum refining. Known for its exceptional waterproofing and adhesive qualities, bitumen serves as the binder in CRMB, ensuring strong cohesion with aggregates in asphalt mixtures.

CRMB’s production involves blending these components under specific conditions—temperature, duration, and the amount of crumb rubber—to achieve the desired specifications.


The production process of Crumb Rubber Modified Bitumen (CRMB) or rubberized asphalt involves a series of well-defined stages, resulting in a product that optimally combines the advantageous properties of bitumen and crumb rubber. Here is a generalized process:

  1. Crumb Rubber Production: This is the initial phase where waste tires are mechanically ground into fine particles, creating the crumb rubber. The size of these particles typically ranges between 0.6 to 0.8 mm.

  2. Preliminary Blending: The crumb rubber is added to hot bitumen, usually at temperatures around 180°C. The high temperature is necessary for the rubber particles to swell and absorb the bitumen.

  3. Digestion Phase: The mixture is kept at the high temperature for a specific period, known as the digestion or reaction time. This period can vary between 1 to 2 hours and allows for the complete assimilation of the crumb rubber into the bitumen. During this process, the rubber particles swell, soften, and partially dissolve, creating a thicker, more viscous material.

  4. Final Blend: Following the digestion phase, the blend is stirred thoroughly to ensure the crumb rubber is evenly dispersed within the bitumen. This can be achieved by using high-speed shear mills.

  5. Filtration and Storage: The CRMB is filtered to remove any large, undissolved rubber particles. It is then stored at high temperatures to prevent separation before use.

  6. Use in Asphalt Mixture: The final CRMB product is mixed with aggregate material (stones, sand, etc.) to create the asphalt mixture that is used for paving.

Please note that the specifics of the production process may vary depending on the required properties of the CRMB, local regulations, and the technology available. Regardless of these factors, the goal is always to produce a superior pavement binder that can resist deformation, cracking, and weathering more effectively than conventional bitumen.


Crumb Rubber Modified Bitumen (CRMB) is an innovative form of bitumen, fortified by the inclusion of crumb rubber, which are finely ground particles extracted from waste tires. This unique combination boosts the performance and durability of bitumen, significantly enhancing road longevity. The varied grades of CRMB, differentiated by the rubber content and the production method, are specifically designed for distinct climates, road networks, and traffic volumes.

The three primary grades of CRMB are:

  1. CRMB 60: Tailored for warm climates, this grade blends bitumen with crumb rubber to enhance the elasticity of bitumen and increase its softening point, making it more resistant to high temperatures. It consequently reduces the risk of rutting and heat-related damage to the road surface.

  2. CRMB 55: This grade is suitable for general climates where temperatures fluctuate considerably throughout the year. It ensures optimal performance under a range of temperatures and is ideal for a variety of road construction projects, including highways, urban roads, and residential streets.

  3. CRMB 50: For colder climates with frequent sub-zero temperatures, CRMB 50 is the preferred choice. This formulation maintains flexibility at lower temperatures, thereby reducing the likelihood of thermal contraction-induced cracking. The added crumb rubber enhances the bitumen’s resistance to cold-temperature cracking and thermal fatigue.

Additionally, CRMB is available in different types based on the rubber content:

  1. Type A CRMB: Comprising 18-22% rubber, it’s produced by adding dry crumb rubber to hot bitumen. This type is ideal for high-traffic roads and highways, where the pavement must withstand heavy loads and extreme weather conditions.

  2. Type B CRMB: Contains 12-16% rubber and is produced by integrating wet crumb rubber with hot bitumen. It’s suitable for low-traffic roads and pavements, where the pavement must endure moderate loads and weather conditions.

  3. Type C CRMB: Comprising 6-10% rubber, this type is generated by adding wet crumb rubber to cold bitumen. It’s appropriate for thin pavements such as bike lanes and footpaths, where the pavement needs to be flexible and resilient.

CRMB can be procured in two forms: wet mix and dry mix. Wet mix CRMB is created by adding wet crumb rubber to hot bitumen and thoroughly amalgamating the components. Dry mix CRMB, on the other hand, is created by adding dry crumb rubber to hot bitumen and blending the mixture using a high-speed mixer.

The various grades, types, and forms of CRMB have a multitude of applications in road construction, determined by the pavement’s design, traffic volume, and climate conditions. High-traffic roads usually employ Type A or wet mix CRMB for its homogeneous and durable mixture. Conversely, low-traffic roads opt for Type B or dry mix CRMB due to its ease of handling and storage. Type C CRMB is typically used for thin pavements like bike lanes and footpaths, where flexibility and durability are crucial.

The production of CRMB can be achieved using two methods: the wet process and the dry process. Both involve blending crumb rubber with hot bitumen in a high-speed mixer. The wet process employs wet crumb rubber, whereas the dry process uses dry crumb rubber ground into a fine powder. The resulting CRMB is stored in a heated storage tank and transported to the construction site in insulated tankers, ensuring its optimal quality and performance for the specific application.


CRMB must meet specific specifications to ensure its quality and performance in road construction. The specifications may vary depending on the country and the project requirements, but the most common ones are as follows:

  • Penetration: the depth in tenths of a millimeter to which a standard needle will penetrate the CRMB sample under specified conditions of temperature and loading.
  • Softening point: the temperature at which the CRMB sample softens and deforms under specified conditions of heating.
  • Viscosity: the resistance of the CRMB sample to flow under specified conditions of temperature and shear rate.
  • Elastic recovery: the percentage of the original deformation that the CRMB sample recovers after being subjected to a specified deformation and relaxation cycle.
  • Fatigue life: the number of load repetitions that the CRMB sample can withstand before failure under specified conditions of temperature and loading.

Specifications For All Grades of CRMB

1Penetration at 25 ֯C, 1/10mm, 100g, 5 sec< 70< 60< 50D5
2Softening Point, (R&B), ֯C, Min505560D36
3Elastic Recovery at 15 ֯C ,%, Min 505050D6084
4Flash point , COC, ֯C , Min220220220D92
5Separation, Difference in Softening Point,(R&B), ֯C, Max444
6Viscosity at 150 ֯C, Poises1-32-63-9D2170/D4402
Thin Film Oven Test & Test on Residue
7aLoss in Mass, %, Max1.01.01.0D6
7bReduction in Penetration of residue at 25 ֯C , 100g, 5s, %,Max404040D5
7cIncrease in Softening Point, ֯C, Max765D36
7dElastic Recovery at 25 ֯C, %, Min353535D6085

Benefits of Opting for CRMB Instead of Traditional Bitumen

Traditional BitumenCrumb Rubber Modified Bitumen (CRMB)
6 to 8 cm Topcoat Asphalt Thickness5 to 7 cm Topcoat Asphalt Thickness
1 to 5 Years Road Lifetime5 to 15 Years Road Lifetime
High Maintenance CostExtremely Low Maintenance Cost
Low Stability Under High LoadsVery High Stability Under High Loads
Extremely Low FlexibilityExtremely High Flexibility
Moderate Skid ResistanceHigh Skid Resistance
Low Fatigue ResistanceHigh Fatigue Resistance
Low Elastic Recovery Causes Asphalt DeformationHigh Elastic Recovery Resists Asphalt Deformation
Moderate Resistance to High and Low TemperatureHigh Resistant to Extreme High and Low Temperature
Low UV Protection Causes Early AgingHigh UV Protection Increases Lifetime
Moderate Car Cabin Noise PenetrationLow Car Cabin Noise Penetration(Up to 4dB)


CRMB is a mixture of bitumen and crumb rubber and does not have a specific chemical formula or CAS number. However, it is classified under the Harmonized System (HS) code 2715.00.90, which covers bituminous mixtures based on natural asphalt, petroleum bitumen, mineral tar or mineral asphalt, mineral wax, and mixtures thereof. The HS code is used by customs authorities to classify goods and determine the applicable duties and taxes.


CRMB has several properties that make it an attractive alternative to conventional bitumen in road construction. Some of these properties are:

  • Improved fatigue resistance: CRMB can withstand repeated loading cycles without cracking or breaking, which improves the pavement’s durability and lifespan.
  • Increased stiffness: CRMB has a higher stiffness modulus than conventional bitumen, which reduces rutting and deformation under heavy loads and high temperatures.
  • Improved adhesion: CRMB forms a stronger bond with aggregates and other materials than conventional bitumen, which improves the pavement’s resistance to water and shear stresses.
  • Reduced aging: CRMB contains antioxidants and anti-oxidant additives that reduce the effects of oxidation and aging, which improves the pavement’s resistance to cracking and embrittlement.
  • Reduced noise: CRMB has a higher content of crumb rubber, which improves the pavement’s noise-absorbing properties and reduces tire-pavement noise.


CRMB has several advantages over conventional bitumen in road construction, such as:

  1. Improved pavement performance: CRMB improves the pavement’s durability, stability, and resistance to deformation, fatigue, and cracking, which reduces maintenance costs and extends the pavement’s lifespan.
  2. Environmental benefits: CRMB recycles waste tires and reduces their disposal in landfills, which reduces the environmental impact of waste and conserves natural resources.
  3. Cost-effectiveness: CRMB is cost-effective compared to other pavement materials, such as concrete, and reduces the construction time and traffic disruptions.
  4. Versatility: CRMB can be used in various pavement applications, such as high-traffic roads, low-traffic roads, thin pavements, and urban areas, which increases its versatility and adaptability to different design and climate conditions.


CRMB is a hazardous material and requires proper handling, storage, and transportation to ensure the safety of workers, the public, and the environment. Some safety tips for handling CRMB are:

Wear protective clothing and equipment, such as gloves, goggles, and respirators, when handling CRMB to prevent skin contact, eye irritation, and inhalation of fumes.

Store CRMB in a heated storage tank or insulated container to prevent it from freezing or solidifying, which can cause blockages and accidents.

Transport CRMB in insulated tankers or containers that are properly labeled and secured to prevent spills, leaks, and fires.

Dispose of used CRMB and contaminated materials in accordance with local regulations and guidelines to prevent environmental contamination and health hazards.


CRMB has a wide range of applications in the road construction industry, including:

  • Asphalt mixtures: CRMB can be used as a binder modifier in asphalt mixtures to improve the pavement’s performance, reduce rutting and cracking, and extend its service life. CRMB can also enhance the resistance of the asphalt mixture to aging, oxidation, and moisture damage.
  • Surface treatments: CRMB can be used as a surface treatment on existing pavements to enhance their skid resistance, prevent raveling, and seal surface cracks. Surface treatments with CRMB can also provide a cost-effective alternative to pavement rehabilitation and reconstruction.
  • Asphalt emulsions: CRMB can be used as an emulsifier in asphalt emulsions to improve their stability and performance. Asphalt emulsions with CRMB can be used as tack coats, fog seals, and chip seals to enhance the bond between asphalt layers and improve the pavement’s durability and resistance to water damage.
  • Warm mix asphalt: CRMB can be used as a warm mix asphalt additive to reduce the mixing and compaction temperatures of asphalt mixtures, which can save energy, reduce emissions, and improve the workability and durability of the pavement.
  • Polymer modified asphalt: CRMB can be combined with polymer modifiers to create polymer modified asphalt (PMA), which can improve the pavement’s performance and resistance to deformation, cracking, and aging.


The installation of Crumb Rubber Modified Bitumen (CRMB) largely follows the same procedure as traditional bitumen, with a few added steps to ensure the unique properties of the material are fully utilized. Below is a generalized process:

  1. Material Preparation: First, the CRMB is prepared according to the specifications of the project. This involves creating a mixture of CRMB and aggregates, which include materials like stones and sand.

  2. Heating: The CRMB mixture is heated to a certain temperature before application, usually around 160 to 170°C. It’s crucial to maintain this temperature range to prevent the premature cooling of the mixture, which can affect its workability and the quality of the finished surface.

  3. Transportation: The heated CRMB mixture is then transported to the construction site. Again, it’s essential to maintain the mixture at the proper temperature during transport.

  4. Placement: Upon arrival at the site, the mixture is placed on the prepared surface using a paving machine. The CRMB mixture is spread evenly across the area to be paved.

  5. Compaction: After placement, the mixture is compacted using rollers to ensure a uniform, dense surface. Proper compaction is crucial to the performance and longevity of the road. This process must be completed before the mixture cools and hardens.

  6. Curing: Finally, the paved surface is left to cure and harden. This can take a few hours to a few days depending on the specific mix and environmental conditions.

The successful installation of CRMB requires careful planning and execution. From the accurate preparation of the CRMB mixture to maintaining the proper temperature during transportation and installation, every step of the process plays a role in achieving a high-quality, durable road surface. It’s also worth noting that different projects may require specific installation techniques or additional steps based on local conditions and regulations.


Maintenance for Crumb Rubber Modified Bitumen (CRMB) roads largely parallels that of traditional asphalt pavements, although the improved properties of CRMB may lead to less frequent maintenance interventions. Here are a few key aspects of maintenance for CRMB roads:

  1. Routine Inspections: Regular inspections are crucial to identify early signs of distress such as rutting, cracking, or potholes. Timely identification and repair of these issues can prevent more significant damage and costly repairs.

  2. Surface Treatments: Surface treatments like seal coating can help preserve the surface of the road and extend its lifespan. These treatments can provide a protective layer, helping to resist weathering and oxidation, and maintain surface texture for skid resistance.

  3. Crack Sealing: Despite CRMB’s enhanced resistance to cracking, any cracks that do appear should be promptly sealed. This can prevent water from infiltrating into the pavement structure and causing more extensive damage.

  4. Pothole Repairs: Similar to cracks, potholes can be more effectively repaired if they are addressed quickly. Potholes in CRMB pavements can be patched using a suitable bituminous material.

  5. Resurfacing or Overlay: If the CRMB road shows signs of significant wear or distress, it may be necessary to apply a new layer of asphalt (an overlay) or to completely resurface the road. This typically involves removing the top layer of the existing pavement and replacing it with a new layer of CRMB.

  6. Drainage Maintenance: Ensuring proper drainage is crucial to prevent water-related damage. This includes keeping ditches, culverts, and storm drains clear of debris and making sure they are functioning correctly.

  7. Routine Cleaning: Regular sweeping can remove debris that may potentially damage the road or lead to drainage problems.

While CRMB roads often exhibit superior performance and longer service lives compared to traditional bitumen pavements, regular maintenance is still essential to maximize their lifespan and keep them in good condition. The specific maintenance needs and schedule will depend on the exact composition of the CRMB, the local climate, the volume and type of traffic, and other factors.


Crumb Rubber Modified Bitumen (CRMB) is known for its enhanced durability compared to traditional bitumen, making it an excellent choice for road construction, particularly in regions experiencing extreme weather conditions or high traffic volume. This increased durability stems from several unique properties of CRMB:

  1. Enhanced Elasticity: CRMB exhibits superior elasticity due to the incorporation of crumb rubber. This allows it to better accommodate the contraction and expansion caused by temperature fluctuations, reducing the likelihood of cracking and rutting.

  2. Increased Resistance to Deformation: High temperatures and heavy traffic can cause road surfaces to deform, leading to rutting. The increased rut resistance of CRMB contributes to its superior durability as it withstands deformation under these conditions.

  3. Superior Aging Properties: CRMB has improved aging properties. The crumb rubber slows down the oxidation process of the bitumen, which helps prevent brittleness and maintains the pavement’s flexibility over time.

  4. Water Damage Resistance: The crumb rubber within the CRMB creates a tighter, more flexible binder-aggregate matrix, which improves resistance to water damage and stripping, hence prolonging the service life of the pavement.

  5. Fatigue Resistance: CRMB’s enhanced elasticity also improves its resistance to fatigue cracking, a common type of distress in asphalt pavements subject to repeated loads.

These beneficial properties translate to reduced maintenance costs, longer road life, and improved driving conditions, making CRMB an environmentally friendly and cost-effective option for road construction projects. The specific durability of CRMB will vary depending on several factors including the precise formulation of the CRMB, the design and construction of the pavement, and the specific conditions (traffic, climate, etc.) to which the pavement is exposed.


The performance of Crumb Rubber Modified Bitumen (CRMB), or rubberized asphalt, greatly surpasses traditional bitumen in several key areas. Its unique properties make it a preferred material for road construction projects, offering enhanced functionality under various conditions:

  1. Elasticity: CRMB possesses greater elasticity due to the incorporation of rubber particles. This elasticity allows it to recover after being deformed by heavy traffic or temperature changes, reducing the likelihood of permanent deformation or rutting.

  2. Resistance to Cracking: The enhanced flexibility of CRMB reduces its susceptibility to both low-temperature cracking (caused by contraction in cold weather) and fatigue cracking (caused by repeated traffic loads).

  3. Thermal Stability: CRMB maintains its physical properties over a broader temperature range compared to traditional bitumen. This makes it suitable for regions with extreme temperatures, and it’s less likely to soften excessively in high temperatures or become brittle in low temperatures.

  4. Rutting Resistance: Under heavy traffic loads or high temperatures, conventional bitumen might form ruts or grooves. CRMB offers higher resistance to this form of road distress, enhancing road safety and longevity.

  5. Reduced Noise Pollution: CRMB pavements have been observed to reduce tire-road noise, making it an attractive solution for urban areas or highways near residential zones.

  6. Increased Skid Resistance: Asphalt made with CRMB often has a higher skid resistance, which can lead to improved road safety, particularly in wet conditions.

  7. Durability: Thanks to its superior resistance to common forms of road wear and distress, CRMB pavements generally have a longer service life. This leads to lower lifecycle costs for road infrastructure.


In the world of road construction and maintenance, Crumb Rubber Modified Bitumen (CRMB) has emerged as a sought-after material that greatly enhances the durability of the roadways. With the rising global demand for CRMB, understanding the market, especially in a leading manufacturing hub like Iran, becomes crucial.

The price of Crumb Rubber Modified Bitumen is a key factor influencing its global and local market dynamics. The price varies based on several factors such as quality, production cost, and the volatile nature of the petroleum industry. Iran, being an abundant source of petroleum, provides a competitive Crumb Rubber Modified Bitumen price in the global market.

As of 2023, the Iran Crumb Rubber Modified Bitumen price is relatively stable compared to the international market, making it an appealing choice for buyers. The market price of Crumb Rubber Modified Bitumen fluctuates in line with the changing costs of raw materials, production, and logistics.

To help buyers make informed decisions, manufacturers usually provide a Crumb Rubber Modified Bitumen (CRMB) price list that includes different grades and quantities of the product. Price list of Crumb Rubber Modified Bitumen in Iran, specifically, assists both domestic and international buyers to plan their purchases effectively.

The Crumb Rubber Modified Bitumen market is serviced by a plethora of sellers, suppliers, and manufacturers. Iran, known for its robust petroleum industry, hosts numerous Crumb Rubber Modified Bitumen manufacturers, suppliers, and sellers. These Iran Crumb Rubber Modified Bitumen suppliers and manufacturers are renowned for their high-quality product offerings, and they continually contribute to the country’s substantial exports.

Companies like Petro Naft, one of the reliable Crumb Rubber Modified Bitumen manufacturers in Iran, have contributed significantly to the industry’s growth. We produce and supply high-quality CRMB both nationally and internationally. You can buy Crumb Rubber Modified Bitumen or plan a purchase of Crumb Rubber Modified Bitumen from trusted suppliers such as Petro Naft.

Iranian refineries, plants, and firms play a pivotal role in shaping the Crumb Rubber Modified Bitumen market price. The product’s superior quality, coupled with the country’s strategic location, provides the Iranian Crumb Rubber Modified Bitumen manufacturers with a competitive edge in the market.

For anyone asking “Where to buy Crumb Rubber Modified Bitumen?”, the answer lies in exploring the Iranian market. Not only are there many nearby Crumb Rubber Modified Bitumen manufacturers, but the chances of getting quality material at a reasonable price are also high.

In conclusion, the market for Crumb Rubber Modified Bitumen (CRMB) in Iran is both dynamic and promising. With manufacturers like Petro Naft at the helm, the supply of high-quality CRMB is ensured. Whether you are a buyer seeking the current Crumb Rubber Modified Bitumen price, or a contractor looking for reliable Crumb Rubber Modified Bitumen (CRMB) sellers in Iran, it is clear that the Iranian CRMB market has much to offer.

Stay updated with the latest prices of our wide range of Petronaft bitumen types. Explore the information on this page for weekly price updates and make informed decisions for your projects:


We produce Crumb Rubber Modified Bitumen CRMB of the best quality in a variety of types and grades and export them from Iran and the United Arab Emirates to other nations worldwide.

  • Crumb Rubber Modified Bitumen Iran ( CRMB Iran )
  • Crumb Rubber Modified Bitumen Emirates ( CRMB Emirates )


CRMB is typically packaged in bulk tanker trucks or drums for transportation and storage. Bulk tanker trucks are the most common packaging method for large-scale projects, while drums are used for small-scale projects or remote areas. The packaging of CRMB must comply with the local regulations and safety standards to prevent spills, leaks, and other hazards during transportation and storage.


CRMB transportation and storage require proper safety precautions and guidelines to ensure the safety of workers, the environment, and the pavement quality. The following are some safety tips for CRMB transportation and storage:

Transport CRMB in dedicated tanker trucks that are designed and equipped for hazardous materials transportation.

Store CRMB in dedicated storage tanks or containers that are made of corrosion-resistant materials and have proper ventilation, heating, and insulation systems.

Use proper personal protective equipment (PPE) when handling CRMB, such as gloves, goggles, respirators, and protective clothing.

Train workers on the safe handling, storage, and transportation of CRMB and provide them with emergency response plans and procedures.

Comply with the local regulations and safety standards for CRMB transportation, storage, and disposal, and obtain the necessary permits and approvals from the relevant authorities.

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