What is the use of colored bitumen in road construction?
Colored bitumen is more resistant to heat and cold than normal black bitumen, and this is due to the use of polymer, which improves and strengthens the asphalt layer. In many countries, instead of painting to mark sections Different highways use colored asphalt. Colored bitumens contain various mineral pigments including titanium dioxide. Colored bitumen is obtained by mixing bitumen with pigments. These pigments are divided into two categories, organic and inorganic, and the most important type of organic pigment is azopigman, which consists of aromatic hydrocarbons. And one of the most common inorganic pigments is iron oxide, which is divided into two natural and synthetic types, and most of the time, red iron oxide and green chromium oxide are used to mix with bitumen and produce a colored mixture. These pigments are stable in all weather conditions, but organic pigments extracted from insects and plants are unstable against heat and weather conditions, expensive and not suitable for mixing with bitumen.
In road construction, pigments such as red iron oxide, green chromium oxide, and titanium dioxide are preferred for producing colored asphalt mixtures due to their excellent heat resistance. Titanium dioxide, an inorganic pigment with a high refractive index, is commonly used to achieve a white color. Red iron oxide stands out as one of the most suitable pigments for bituminous mixtures, although with asphaltene-free bitumens, a wider range of colors can be obtained, ranging from yellow to blue.
Vibrant and vivid colors are achievable solely when using colorless binders. These binders, devoid of asphaltene content, exhibit high colorability. By incorporating yellow, brown, and black iron oxide, as well as green chromium oxide, a diverse palette of colors can be achieved with these binders, provided they possess excellent thermal resistance. It is important to note that yellow and black iron oxides tend to transform into red iron oxide at temperatures exceeding 180°C, which is typically the mixing temperature in asphalt production. For yellow coloration, zinc ferrite products with high thermal resistance are employed, while a blend of manganese and iron oxides is utilized for brown and gray shades.
Colorless bitumen is available only in select countries, although it carries certain disadvantages, including high cost and low resistance to climate change. However, when utilizing colorless bitumen, it becomes easier to produce a broader range of colored products by incorporating approximately 1-2% of pigments.
Rubber powder is commonly used in the modification of bitumen 60/70 to enhance its properties and performance. Here are a few examples of how rubber powder is commonly utilized in bitumen 60/70 modification:
1. Rubberized Bitumen Binder: Rubber powder is added to bitumen 60/70 to create a rubberized bitumen binder. This modified binder exhibits improved elasticity, flexibility, and resistance to cracking compared to traditional bitumen. It is commonly used in road construction for asphalt pavements, where it helps to enhance the durability and longevity of the pavement.
2. Polymer-Modified Bitumen (PMB): Rubber powder can be incorporated into bitumen 60/70 as part of polymer-modified bitumen formulations. PMB is created by blending bitumen with polymers, such as styrene-butadiene-styrene (SBS) or ethylene-vinyl acetate (EVA). The addition of rubber powder further enhances the elasticity and deformation resistance of the PMB, making it suitable for areas with high traffic loads and challenging climatic conditions.
3. Crumb Rubber Modifier (CRM): Rubber powder derived from recycled tires, known as crumb rubber, can be used as a modifier in bitumen 60/70. The crumb rubber is mixed with bitumen to form a crumb rubber-modified bitumen (CRMB). This modification improves the bitumen's properties, such as elasticity, viscosity, and resistance to rutting and fatigue cracking. CRMB is commonly utilized in road resurfacing projects to enhance the performance and sustainability of the asphalt pavement.
4. Warm Mix Asphalt (WMA): Rubber powder can also be incorporated into bitumen 60/70 for the production of warm mix asphalt. Warm mix asphalt technologies allow for lower mixing and compaction temperatures compared to traditional hot mix asphalt (HMA). The addition of rubber powder helps to lower the viscosity of the bitumen, allowing it to be mixed and compacted at lower temperatures. This reduces energy consumption, emissions, and potential damage to the asphalt mixture during the production process.
These are some of the common applications of rubber powder in bitumen 60/70 modification. The specific formulation and dosage of rubber powder may vary depending on the desired properties and performance requirements of the asphalt mixture.
Adding rubber powder to bitumen 80/100 offers several benefits beyond reducing thermal sensitivity. Here are some additional advantages:
1. Improved Elasticity and Flexibility: Rubber powder enhances the elasticity and flexibility of bitumen 80/100. This improved flexibility allows the modified bitumen to better accommodate dynamic loads and resist cracking, rutting, and deformation. It helps to maintain the integrity of the pavement under heavy traffic and varying temperature conditions.
2. Increased Resistance to Aging: Rubber-modified bitumen exhibits increased resistance to aging compared to conventional bitumen. The rubber particles act as antioxidants, protecting the bitumen from oxidative degradation caused by exposure to UV radiation and atmospheric oxygen. This leads to improved durability and longer service life of the asphalt pavement.
3. Enhanced Rutting Resistance: Rutting, or permanent deformation of the asphalt pavement under traffic loads, is a common issue in road construction. Rubber powder improves the rutting resistance of bitumen 80/100 by enhancing its elastic recovery and resistance to shear deformation. This results in a more stable and durable pavement that can withstand heavy traffic loads without significant rutting.
4. Improved Crack Resistance: Rubber-modified bitumen exhibits improved resistance to cracking. The rubber particles distribute stress more effectively, reducing the formation and propagation of cracks in the asphalt pavement. This helps to maintain the structural integrity of the pavement and reduces the need for frequent repairs or maintenance.
5. Enhanced Sound Absorption: Rubber-modified bitumen has sound-absorbing properties, making it suitable for applications where noise reduction is desired. The rubber particles help to mitigate road noise by absorbing and dampening sound waves, resulting in a quieter road surface.
6. Sustainable Use of Recycled Materials: Incorporating rubber powder derived from recycled tires in bitumen 80/100 promotes the sustainable use of waste materials. It helps reduce the environmental impact of discarded tires while improving the performance of the asphalt pavement.
Overall, the addition of rubber powder to bitumen 80/100 provides enhanced elasticity, flexibility, resistance to aging, rutting, and cracking. These benefits contribute to the longevity, durability, and sustainability of asphalt pavements.
ATDM CO is a manufacturer and exporter of Bitumen 60/70 and bitumen 80/100, offering three different quality grades available in drums, bags, and bulk quantities. Our products are classified into premium, second, and third types, each with varying production costs and facilities. We provide a wide range of options to accommodate different customer needs and volume requirements.
