Asphalt-based coatings process

Several Pseudomonas spp. have been documented in the literature as common contaminants and derivatives of petroleum fluids (aromatic and paraffinic hydrocarbons, kerosene fuels, cutting oil emulsions), as well as, asphalt and asphalt-based coatings. Generally, their presence produces an alteration of fuel quality which leads to slime formation and subsequent blockages of filters and injection systems. In addition, several types of corrosion processes have been demonstrated which primarily involve pitting (Genner and Hill, 1981). Occasionally, the presence of marcescens has been reported in association with... 

Over the years, multilayers of tar-based waterproofers replaced the hot asphalt used in roofing. In early 1900, asphalt became available from petroleum refining, and it was followed by oxidized bitumen interlaid with roofing felt and then alternated with a mineral base sheet, l" Asphalt-based materials are used extensively as binders, sealants, and waterproof coatings in diverse applications because of their low cost, inherent cohesive nature, weather-resistant properties, and ease of processing in the molten state. 

Recent trends in protective coatings used on buried pipelines have been away from reinforced hot applied coal tar and asphalt enamels and butyl rubber laminate tapes, particularly where applied over-the-ditch . The more recently developed coatings based on fusion bonded epoxies, extruded poly-ethylenes, liquid-applied epoxies and polyurethanes, require factory application where superior levels of pipe preparation and quality control of the application process can be achieved. 

Sulfur, modified in its structure so as to become plastic, presents other problems as it can be a very ductile material. Reinforcement in the sense of load sharing may be effected by incorporating relatively ductile thermoplastic fibers. There is a commercial interest in using polypropylene fibers, and Bennett (10,11) has patented a process whereby woven polypropylene fibers are impregnated with asphalt or bitumen and then are coated on at least one side with a sulfur composition. The plasticized sulfur coating sticks to the base and makes the laminate flexible, weather resistant, and light reflecting. 

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