Intro of Blown Asphalt
Blown Asphalt is produced by the Continuous or Staggered Blowing Process, where hot Penetration Grade Bitumen is blown in controlled conditions through the air in order to regulate oil content and oxidation. The resulting product has increased rubbery properties, making it more hard than its parent material.
Blown Asphalt has overall use in industries, including construction, waterproofing, roofing, and automotive. It is an anti-slip coating, electric cable protector, and joint sealant. It has other uses in bituminous marine mastic in oil and gas pipelines. Low thermal sensitivity, it still possesses a high softening point and penetration index (8>PI>2), making it suitable for use.
Produced by air-blowing penetration grade bitumen at high temperatures, Blown Asphalt is graded by numbers indicating softening point and penetration. It is available in solid or semi-black shape which melts gradually when heated. Softening point is analyzed according to ASTM D36, whereas penetration is calculated in terms of ASTM D5 or IP49 tests.
Blown Asphalt is available in different grades, including 115/15, 90/40, 75/25, 85/25, 90/15, 105/35, 150/5, 95/25, and special order on request.
Process
The production of Blown Asphalt involves several key steps: tank loading, bitumen blowing, gas condensation, and packaging. Loose bitumen is loaded into storage tanks and warmed for easy pumping into the blowing tower first. When the tower isn’t being loaded, hot bitumen is loaded directly, packing the tower up to 70% in order to prevent overloading. 190-230°C air is blown in, with oxidation at the ideal temperature of 265-270°C. Temperature is controlled by a burner, explosion hazard precautions.
The process terminates when Blown Asphalt achieves the desired properties depending on sampling and testing. The bitumen is final-heated after being oxidized, and then transported to storage or packaging. Volatile substances and gases released are separated, treated, and burned in the furnace. Loading and packaging can begin after cooling the material to 150-160°C. Oxidised bitumen transfer is pump-free due to the liquid level of the tower. Filling occurs in drums and 25kg cartons with multiple taps to ensure efficiency as well as avert hardening during filling.
Blown Bitumen Application
The most commonly requested Blown Asphalt grades are 95/25, 85/25, 90/40, and 115/15, with special grades ordered to specification. Because it has such a high softening point, it is an excellent sealant to maintain bleeding away from high-heat applications. Blown Asphalt is used in piling as an anti-slip compound, auto undercarriage sealants, joint filling, roofing felts, sound dampening, and bituminous marine mastic for oil and gas pipelines.
Bituminized Oxidized is most suitable for waterproofing saw cut and joint fillings with little or no movement and finds wide application in roofing, floorings, mastic, pipelining coating, and electrical applications. Bituminized Oxidized finds its applications in carpet backing, anticorrosive protection, acoustical paneling, and paint manufacture.
The production process is air-blowing, where air blows asphalt at high temperatures, resulting in a harder, more viscous, and less volatile product. Oxidized asphalt is used in roofing, pipe coatings, pavement undersealing, hydraulic applications, and membrane envelopes. Coating asphalt is used in various roofing systems, including asphalt shingles and modified bitumen roofing, which include polymers such as APP or SBS for better performance on commercial and industrial low-slope roofs.
Blown Asphalt Packing
Blown Asphalt is packed tightly to prevent cooling and hardening in processing. It is usually packed in drums and cartons of 25kg. Due to the liquid level in the blowing tower, the material is gravity-fed without the use of pumps. Multiple taps are available to fill multiple drums and cartons simultaneously, which enables a quick and smooth process. Once the bitumen cools to 150-160°C, it can be transported and delivered. Proper packaging ensures safe transport and storage with the quality of the product intact.
Specification
Among these bitumen, the most widely used Blown Asphalt in the market is R85/25, with a softening point of 85 and a penetration grade of 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 D6
- Flashpoint: ASTM D92
- Solubility: ASTM D4
- Ductility: ASTM D113
- Spot test: AASHTO T 102
ZUMRUT INT Co is a vibrant company that is involved in the production, purchase, distribution, and exportation of various grades of Blown Asphalt. Having an exclusive oxidization section, the company meets global customers’ needs, exporting bitumen plants, asphalt companies, roof insulation firms, and membrane sheet manufacturers. Blown Asphalt, being one of over seven types of bitumen produced worldwide, is highly valued for its water resistance and heat fluctuation tolerance, as well as toughness and elasticity. ZUMRUT INT Co also offers custom Blown Asphalt grades based on the specifications of the client, thus it is a flexible and reliable product for use in industries.
