The oxidation may be performed using air, nitrogen, oxygen, carbon dioxide, chlorine, another suitable oxidizing gas, or a combination of these gases at a time and temperature such that any needed or desired characteristic of the bio-source material or the bitumen source material (for example, softening point, penetration distance, viscosity, another suitable parameter, or any combination thereof) is achieved. In one embodiment, the oxidation can be performed in the absence of air. In a particular embodiment, the oxidation may be performed at a temperature in a range of approximately 100° C. (212° F.) to approximately 235° C. (455° F.). In a particular embodiment, the catalyst for oxidation is provided in a liquid form. In another particular embodiment, the oxidation can be performed without the addition of a catalyst. The oxidation can be performed until a needed or desired characteristic of the bitumen for example, softening point, penetration distance, viscosity, another suitable parameter, or any combination thereof is achieved. After reading this specification, skilled artisans will be able to determine the particular conditions used for the oxidation. For the purposes of this specification, an oxidised asphalt material includes a partially blown asphalt source, such as partially oxidized petroleum-based bitumen asphalt.
The oxidized grade of bitumen using as
Two types of blown asphalt coated roofing materials are available; built up roofs, and roofs made of roofing shingles. Built up roofing is the type used on horizontal type roof structures which are typically commercial or apartment type buildings. For the built up roofs, blown asphalt is heated to 400°-450° F., and then mopped on. The saturated bitumen felt is then rolled over. The asphalt which acts both as an adhesive as well as a water-proofing coating, is applied as the roof is being layed down. Because the oxidised asphalt for built up roofing must retain adhesive properties, it is less cross linked or mildly oxidized compared to asphalt prepared for roofing shingles. Roofing stone aggregate is spread over the entire built up roof to provide weather resistance to the built up roof. Roofing stone aggregate can be stone or slag. Its purpose is to prevent ultraviolet rays from degrading the roof coating. The stone allows walking over the roof without disturbing the asphalt.
Roofing shingles are another type of roofing material coated with blown asphalt. The bitumen is cross linked or oxidized and is coated onto the roofing felt in a manufacturing step. Generally, the asphalt is filled with stone dust. The asphalt is heated to about 400°-450° F. and spread on and pressed into the roofing felt. Roofing granules are then fed onto the saturated asphalt felt and pressed in.
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