Bitumen coatings

Composition. Bitumen paints contain bituminous substances as binders. Bitumen is defined in DIN 55 946 as A low-volatile, darkly-colored mixture of organic substances obtained in the processing of mineral oils and petroleum, whose viscoelastic behavior changes with temperature. The typical properties of bitumen can be attributed to a colloidal system in which the disperse phase (asphaltenes) is stably distributed in a coherent phase of high-boiling oils (maltenes).  

Bitumens are thermoplastic, weather resistant, water resistant, absorb very little water, do not release any toxic substances in water, and are soluble in hydrocarbons. 

Depending on the application, relatively hard distillation bitumen, oxidation bitumen, or high-vacuum bitumen (hard bitumen) are used for physically drying bitumen paints. Waterborne bitumen paints and thick coatings (bitumen emulsions) are produced from moderately hard distillation bitumen. 

Petroleum fractions and aromatic hydrocarbons with a boiling point range between ca. 130 and 200°C are suitable solvents for bitumen solutions. Benzines (mineral spirit) are preferred on account of their less obtrusive smell and the fact that they are more environmentally friendly. On account of their toxic properties, chlorinated hydrocarbons are no longer used. 

Waterborne bitumens may be anionic, cationic, or rarely nonionic emulsions, and are produced with the aid of emulsifiers and, if necessary, stabilizers conventionally used in the paint industry. The properties of bitumen paint (solutions and emulsions) (e.g., stability mechanical, weather, water, and chemical resistance corrosion protection properties) can be substantially improved by incorporating extenders. Suitable extenders include ground slate, ground limestone, chalk, talc, and mica (25 45 wt%, depending on extender type and required properties). The use of extenders 

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Corrosion protection using bitumen coatings reaches back into antiquity. The most ancient occurrence of bitumen deposits was in Mesopotamia. Many writers of antiquity, such as Dido, Strabo, and Vitruvius, mention that asphalt was obtained for many years near Babylon. About 5000 yeare ago, the streets of Ur, capital of the Sumerians (north of present-day Kuwait), were lit at night with mineral oil. Natural gas was reported to be used for lighting in the Middle East and China. 

Fig. 3-4 Current-potential measurements on a buried steel storage tank with bitumen coating (surface area 4 m with four defects 5 cm x 20 cm soil resistivity p 30Q. m).

Fig. 9-20 Pipe/soil potential of a pipeline with defect-free PE coating (up to 200 m) and with bitumen coating (200 to 600 m) in the region of an anodic voltage cone...

Figure 12-2 shows as an example the arrangement of the anode installation for the local cathodic protection of pipelines in a power station. The cooling water pipelines have a nominal diameter of DN 2000 and 2500 and a covering of earth up to 6 m. The fire-fighting pipelines have a nominal diameter of DN 100 and a covering of 1 m. All the pipelines have a bitumen coating. 

Well casing and pipelines in oilfield Cathodic protection Bitumen coating 1.35... 

With bitumen coating, there is a natural limit to the voltage so that, even under the most unfavorable conditions, pipeline potentials scarcely ever exceed 1.5 kV. With PE coating, a voltage limit is to be expected only at higher pipeline potentials of a few kilovolts. 

Bitumen-coated spunbonded polypropylene fabrics, 17 487 Bituminous coal, 6 703... 

Figure 10. Nyquist plots for bitumen coated mild steel. Day 0 and Day 50.

Even so, the low frequency irtpedance as derived from the noise measurements was still two to three orders of magnitude higher than the bitumen coated system. The better coatings exhibited low frequency impedances some four to five orders of magnitude higher than the bitumen. 

Figure 20. Photographic sequence in which, viewing the images clockwise, an air bubble on the tip of a capillary, is pushed down through an alkaline solution at 80° C until it just touches a layer of bitumen coated onto a silica surface. The bitumen spontaneously spreads over the surface of the bubble, causing it to detach from the capillary and become engulfed. Note the obvious presence of solid particles in the bitumen on the surface in the lower photo. (Photomicrographs by L. L. Schramm, reproduced from reference 69. Copyright 1994 American Chemical Society.)...

Bitumen. Generally based on residues from petroleum or coal mining processes. Bitumen coatings can also come from naturally occurring sources such as gilsonite. The presence of some aromatic hydrocarbons such as benzene in some of these coatings has limited their acceptability in recent times because of environmental and health concerns. 

Protective films, such as paint, bitumen coatings, or oil films... 

Blade mixing is the least precise of the mixed-in-place methods since everything is dependent on the experience of the motor grader operator. In an attempt to achieve uniform and adequate coating, it is possible that bitumen coating is stripped from the aggregate. 

The cure time test is used to determine initial cohesion of slurry mat and resistance to traffic. Total cure of a slurry seal mat is obtained when complete cohesion between bitumen-coated aggregate particles occurs. 

Fig. 2. The wave structures of various coating materials at frequency 28 kHz (a) for bitumen coating, the amplitude of circumferential displacement is vary from the inside wall (position 76 mm) to outside wall (position 83.2 mm) then through the coating material. The relative displacement changes significantly high in the viscous layer (b) for polyethylene coating, the variation of the relative displacement is slightly high in the viscous layer, (c) for mineral wool coating, its relative displacement is near the same as in the viscous layer.

Mineral surfaced roofing n. Felt or fabric saturated with bitumen, coated on one or both sides with a bituminous coating and surfaced on its weather side with mineral granules. 

Stern, B., Connan, I, Blakelock, E., Jackman, R., Coningham, R.A.E., Heron, C. (2008) From Snsa to Anuradhapura reconstructing aspects of trade and exchange in bitumen-coated ceramic vessels between Iran and Sri Lanka from the third to the ninth centuries AD. Archaeometry, 50,409-428. 

Based on microscopic studies, Swanson [128] proposed that the rising bitumen-coated gas bubbles collapse in the froth layer to yield water droplets dispersed in bitumen, as illustrated in Figure 30. This would produce dispersed gas bubbles with diameters just smaller than the original globules and also small water droplets, formed from the original... 

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