Editing Bitumen (section)

== Modern use ==
=== Global use ===
The vast majority of refined bitumen is used in construction: primarily as a constituent of products used in paving and roofing applications. According to the requirements of the end use, bitumen is produced to specification. This is achieved either by refining or blending. It is estimated that the current world use of bitumen is approximately 102 million tonnes per year. Approximately 85% of all the bitumen produced is used as the [[Binder (material)|binder]] in asphalt concrete for roads. It is also used in other paved areas such as airport runways, car parks and footways. Typically, the production of asphalt concrete involves mixing fine and coarse [[Construction aggregate|aggregates]] such as [[sand]], [[gravel]] and crushed rock with asphalt, which acts as the binding agent. Other materials, such as recycled polymers (e.g., [[Natural rubber|rubber]] [[tire|tyres]]), may be added to the bitumen to modify its properties according to the application for which the bitumen is ultimately intended.

A further 10% of global bitumen production is used in roofing applications, where its waterproofing qualities are invaluable.
The remaining 5% of bitumen is used mainly for sealing and insulating purposes in a variety of building materials, such as pipe coatings, carpet tile backing and paint. Bitumen is applied in the construction and maintenance of many structures, systems, and components, such as:

{{div col|colwidth=22em}}
* Highways
* Airport runways
* Footways and pedestrian ways
* Car parks
* Racetracks
* Tennis courts
* Roofing
* Damp proofing
* Dams
* Reservoir and pool linings
* Soundproofing
* Pipe coatings
* Cable coatings
* Paints
* Building water proofing
* Tile underlying waterproofing
* Newspaper ink production
{{div col end}}

=== Rolled asphalt concrete ===
{{Main|Asphalt concrete}}The largest use of bitumen is for making [[asphalt concrete]] for road surfaces; this accounts for approximately 85% of the bitumen consumed in the United States. There are about 4,000 asphalt concrete mixing plants in the US, and a similar number in Europe.<ref name="the_asphalt_paving_industry_2nd_ed">{{cite book | title = The Asphalt Paving Industry: A Global Perspective, 2nd Edition | publisher = National Asphalt Pavement Association and European Asphalt Pavement Association | year = 2011 | location = Lanham, Maryland, and Brussels | url = http://www.asphaltpavement.org/images/stories/GL_101_Edition_3.pdf | access-date = 27 September 2012 | isbn = 978-0-914313-06-9 | archive-date = 7 January 2014 | archive-url = https://web.archive.org/web/20140107203855/http://www.asphaltpavement.org/images/stories/GL_101_Edition_3.pdf }}</ref>
[[File:Pavement layers.png|thumb|[[Asphalt concrete]] is usually placed on top in a road.]]
Asphalt concrete pavement mixes are typically composed of 5% bitumen (known as asphalt cement in the US) and 95% aggregates (stone, sand, and gravel). Due to its highly viscous nature, bitumen must be heated so it can be mixed with the aggregates at the asphalt mixing facility. The temperature required varies depending upon characteristics of the bitumen and the aggregates, but [[Warm-mix asphalt|warm-mix asphalt technologies]] allow producers to reduce the temperature required.<ref name="the_asphalt_paving_industry_2nd_ed" /><ref name="whats_in_your_asphalt_2017_09_fhwa" />

The weight of an asphalt pavement depends upon the [[construction aggregate|aggregate]] type, the bitumen, and the air void content. An average example in the United States is about 112 pounds per square yard, per inch of pavement thickness.<ref name="whats_in_your_asphalt_2017_09_fhwa" />

When maintenance is performed on asphalt pavements, such as [[Pavement milling|milling]] to remove a worn or damaged surface, the removed material can be returned to a facility for processing into new pavement mixtures. The bitumen in the removed material can be reactivated and put back to use in new pavement mixes.<ref>{{cite journal|title=How Should We Express RAP and RAS Contents? |journal=Asphalt Technology E-News |year=2014 |volume=26 |issue=2 |url=http://www.eng.auburn.edu/research/centers/ncat/info-pubs/newsletters/fall-2014/recycledcontents.html |archive-url=https://web.archive.org/web/20150609020500/http://www.eng.auburn.edu/research/centers/ncat/info-pubs/newsletters/fall-2014/recycledcontents.html |archive-date=9 June 2015 }}</ref> With some 95% of paved roads being constructed of or surfaced with asphalt,<ref>{{cite web |url=https://www.fhwa.dot.gov/policyinformation/statistics/2012/hm12.cfm |title=Highway Statistics Series: Public Road Length Miles by Type of Surface and Ownership |publisher=[[Federal Highway Administration]] |date=1 October 2013 }}</ref> a substantial amount of asphalt pavement material is reclaimed each year. According to industry surveys conducted annually by the [[Federal Highway Administration]] and the National Asphalt Pavement Association, more than 99% of the bitumen removed each year from road surfaces during widening and resurfacing projects is reused as part of new pavements, roadbeds, shoulders and embankments or stockpiled for future use.<ref>{{cite web|title=Asphalt Pavement Recycling|url=http://www.asphaltpavement.org/recycling|work=Annual Asphalt Pavement Industry Survey on Recycled Materials and Warm-Mix Asphalt Usage: 2018|publisher=National Asphalt Pavement Association|access-date=14 January 2020|archive-date=23 January 2020|archive-url=https://web.archive.org/web/20200123010627/http://www.asphaltpavement.org/recycling}}</ref>

Asphalt concrete paving is widely used in airports around the world. Due to the sturdiness and ability to be repaired quickly, it is widely used for [[runway]]s.

=== Mastic asphalt ===
[[Mastic asphalt]] is a type of asphalt that differs from dense graded asphalt ([[asphalt concrete]]) in that it has a higher bitumen ([[binder (material)|binder]]) content, usually around 7–10% of the whole aggregate mix, as opposed to rolled asphalt concrete, which has only around 5% asphalt. This thermoplastic substance is widely used in the building industry for waterproofing flat roofs and tanking underground. Mastic asphalt is heated to a temperature of {{convert|210|°C|°F}} and is spread in layers to form an impervious barrier about {{convert|20|mm|in|1|abbr=off|sp=us}} thick.

=== Bitumen emulsion ===
[[File:Bitumenemulsion.jpg|thumb|Volume-weighted particle size distribution of 2 different asphalt emulsions determined by laser diffraction]]
Bitumen emulsions are colloidal mixtures of bitumen and water. Due to the different surface tensions of the two liquids, stable emulsions cannot be created simply by mixing. Therefore, various emulsifiers and stabilizers are added. Emulsifiers are amphiphilic molecules that differ in the charge of their polar head group. They reduce the surface tension of the emulsion and thus prevent bitumen particles from fusing. The emulsifier charge defines the type of emulsion: anionic (negatively charged) and cationic (positively charged).<ref name="Al-Mohammedawi-2022">{{Cite journal |last1=Al-Mohammedawi |first1=Ahmed |last2=Mollenhauer |first2=Konrad |date=9 March 2022 |title=Current Research and Challenges in Bitumen Emulsion Manufacturing and Its Properties |journal=Materials |language=en |volume=15 |issue=6 |page=2026 |doi=10.3390/ma15062026 |issn=1996-1944 |pmc=8952829 |pmid=35329476|bibcode=2022Mate...15.2026A |doi-access=free }}</ref> The concentration of an emulsifier is a critical parameter affecting the size of the bitumen particles—higher concentrations lead to smaller bitumen particles.<ref name="Al-Mohammedawi-2022" /> Thus, emulsifiers have a great impact on the stability, viscosity, breaking strength, and adhesion of the bitumen emulsion.<ref name="Al-Mohammedawi-2022" /> The size of bitumen particles is usually between 0.1 and 50{{nbs}}μm with a main fraction between 1{{nbs}}μm and 10{{nbs}}μm. Laser diffraction techniques can be used to determine the particle size distribution quickly and easily.<ref name="Al-Mohammedawi-2022" /><ref>{{Cite web|url=https://wiki.anton-paar.com/at-de/particle-size-in-building-materials-from-cement-to-bitumen/|title=Particle Size in Building Materials: From Cement to Bitumen |website=Anton Paar}}</ref> Cationic emulsifiers primarily include long-chain amines such as imidazolines, amido-amines, and diamines, which acquire a positive charge when an acid is added.<ref name="Al-Mohammedawi-2022" /> Anionic emulsifiers are often fatty acids extracted from lignin, tall oil, or tree resin saponified with bases such as NaOH, which creates a negative charge.<ref name="Al-Mohammedawi-2022" />

During the storage of bitumen emulsions, bitumen particles sediment, agglomerate (flocculation), or fuse (coagulation), which leads to a certain instability of the bitumen emulsion. How fast this process occurs depends on the formulation of the bitumen emulsion but also storage conditions such as temperature and humidity. When emulsified bitumen gets into contact with aggregates, emulsifiers lose their effectiveness, the emulsion breaks down, and an adhering bitumen film is formed referred to as 'breaking'. Bitumen particles almost instantly create a continuous bitumen film by coagulating and separating from water which evaporates. Not each asphalt emulsion reacts as fast as the other when it gets into contact with aggregates. That enables a classification into Rapid-setting (R), Slow-setting (SS), and Medium-setting (MS) emulsions, but also an individual, application-specific optimization of the formulation and a wide field of application<ref name="Al-Mohammedawi-2022" /> (1). For example, Slow-breaking emulsions ensure a longer processing time which is particularly advantageous for fine aggregates<ref name="Al-Mohammedawi-2022" /> (1).

Adhesion problems are reported for anionic emulsions in contact with quartz-rich aggregates. They are substituted by cationic emulsions achieving better adhesion. The extensive range of bitumen emulsions is covered insufficiently by standardization. DIN EN 13808 for cationic asphalt emulsions has been existing since July 2005. Here, a classification of bitumen emulsions based on letters and numbers is described, considering charges, viscosities, and the type of bitumen.<ref name="Al-Mohammedawi-2022" /> The production process of bitumen emulsions is very complex. Two methods are commonly used, the "Colloid mill" method and the "High Internal Phase Ratio (HIPR)" method.<ref name="Al-Mohammedawi-2022" /> In the "Colloid mill" method, a rotor moves at high speed within a stator by adding bitumen and a water-emulsifier mixture. The resulting shear forces generate bitumen particles between 5{{nbs}}μm and 10{{nbs}}μm coated with emulsifiers.<ref name="Al-Mohammedawi-2022" /> The "High Internal Phase Ratio (HIPR)" method is used for creating smaller bitumen particles, monomodal, narrow particle size distributions, and very high bitumen concentrations. Here, a highly concentrated bitumen emulsion is produced first by moderate stirring and diluted afterward. In contrast to the "Colloid-Mill" method, the aqueous phase is introduced into hot bitumen, enabling very high bitumen concentrations.<ref name="Al-Mohammedawi-2022" />

T The "High Internal Phase Ratio (HIPR)" method is used for creating smaller bitumen particles, monomodal, narrow particle size distributions, and very high bitumen concentrations. Here, a highly concentrated bitumen emulsion is produced first by moderate stirring and diluted afterward. In contrast to the "Colloid-Mill" method, the aqueous phase is introduced into hot bitumen, enabling very high bitumen concentrations (1).he "High Internal Phase Ratio (HIPR)" method is used for creating smaller bitumen particles, monomodal, narrow particle size distributions, and very high bitumen concentrations. Here, a highly concentrated bitumen emulsion is produced first by moderate stirring and diluted afterward. In contrast to the "Colloid-Mill" method, the aqueous phase is introduced into hot bitumen, enabling very high bitumen concentrations (1).

Bitumen emulsions are used in a wide variety of applications. They are used in road construction and building protection and primarily include the application in cold recycling mixtures, adhesive coating, and surface treatment (1). Due to the lower viscosity in comparison to hot bitumen, processing requires less energy and is associated with significantly less risk of fire and burns.<ref name="Al-Mohammedawi-2022" /> [[Chipseal]] involves spraying the road surface with bitumen emulsion followed by a layer of crushed rock, gravel or crushed slag. Slurry seal is a mixture of bitumen emulsion and fine crushed aggregate that is spread on the surface of a road. Cold-mixed asphalt can also be made from bitumen emulsion to create pavements similar to hot-mixed asphalt, several inches in depth, and bitumen emulsions are also blended into recycled hot-mix asphalt to create low-cost pavements. Bitumen emulsion based techniques are known to be useful for all classes of roads, their use may also be possible in the following applications: 1. Asphalts for heavily trafficked roads (based on the use of polymer modified emulsions) 2. Warm emulsion based mixtures, to improve both their maturation time and mechanical properties 3. Half-warm technology, in which aggregates are heated up to 100 degrees, producing mixtures with similar properties to those of hot asphalts 4. High performance surface dressing.<ref>Read, J. and Whiteoak, D., 2003. ''The Shell Bitumen Handbook''. Thomas Telford.</ref>

=== Synthetic crude oil ===
{{Main|Synthetic crude oil}}
{{See also|Petroleum production in Canada}}
Synthetic crude oil, also known as syncrude, is the output from a bitumen upgrader facility used in connection with oil sand production in Canada. Bituminous sands are mined using enormous (100-ton capacity) [[power shovel]]s and loaded into even larger (400-ton capacity) [[dump trucks]] for movement to an upgrading facility. The process used to extract the bitumen from the sand is a hot water process originally developed by [[Karl Clark (chemist)|Dr. Karl Clark]] of the [[University of Alberta]] during the 1920s. After extraction from the sand, the bitumen is fed into a [[Upgrader|bitumen upgrader]] which converts it into a [[light crude oil]] equivalent. This synthetic substance is fluid enough to be transferred through conventional [[oil pipeline]]s and can be fed into conventional oil refineries without any further treatment. By 2015 Canadian bitumen upgraders were producing over {{convert|1|Moilbbl}} per day of synthetic crude oil, of which 75% was exported to oil refineries in the United States.<ref name=NEBstats>{{cite web | url = https://www.neb-one.gc.ca/nrg/sttstc/crdlndptrlmprdct/index-eng.html | title = Crude Oil and Petroleum Products | publisher = [[National Energy Board]] of Canada | access-date = 21 January 2016}}</ref>

In Alberta, five bitumen upgraders produce synthetic crude oil and a variety of other products: The [[Suncor Energy]] upgrader near [[Fort McMurray, Alberta]] produces synthetic crude oil plus diesel fuel; the [[Syncrude Canada]], [[Canadian Natural Resources]], and [[Nexen]] upgraders near Fort McMurray produce synthetic crude oil; and the Shell [[Scotford Upgrader]] near Edmonton produces synthetic crude oil plus an intermediate feedstock for the nearby Shell Oil Refinery.<ref name=CAPP2015>{{cite web|url=http://www.capp.ca/publications-and-statistics/publications/264673 |title=2015 CAPP Crude Oil Forecast, Markets & Transportation |publisher=[[Canadian Association of Petroleum Producers]] |access-date=21 January 2016 |archive-url=https://web.archive.org/web/20160120081514/http://www.capp.ca/publications-and-statistics/publications/264673 |archive-date=20 January 2016 }}</ref> A sixth upgrader, under construction in 2015 near [[Redwater, Alberta]], will upgrade half of its crude bitumen directly to diesel fuel, with the remainder of the output being sold as feedstock to nearby oil refineries and petrochemical plants.<ref>{{cite web | url = http://www.nwrpartnership.com/ | title = The Project | publisher = North West Redwater Partnership | access-date = 21 January 2016}}</ref>

=== Non-upgraded crude bitumen ===
{{See also|Western Canadian Select}}
Canadian bitumen does not differ substantially from oils such as Venezuelan extra-heavy and Mexican [[heavy crude oil|heavy oil]] in chemical composition, and the real difficulty is moving the extremely viscous bitumen through [[oil pipeline]]s to the refinery. Many modern oil refineries are extremely sophisticated and can process non-upgraded bitumen directly into products such as gasoline, diesel fuel, and refined asphalt without any preprocessing. This is particularly common in areas such as the US [[Gulf coast]], where refineries were designed to process Venezuelan and Mexican oil, and in areas such as the US [[Midwest]] where refineries were rebuilt to process heavy oil as domestic light oil production declined. Given the choice, such heavy oil refineries usually prefer to buy bitumen rather than synthetic oil because the cost is lower, and in some cases because they prefer to produce more diesel fuel and less gasoline.<ref name=CAPP2015/> By 2015 Canadian production and exports of non-upgraded bitumen exceeded that of synthetic crude oil at over {{convert|1.3|Moilbbl}} per day, of which about 65% was exported to the United States.<ref name=NEBstats/>

Because of the difficulty of moving crude bitumen through pipelines, non-upgraded bitumen is usually diluted with [[natural-gas condensate]] in a form called [[dilbit]] or with synthetic crude oil, called [[synbit]]. However, to meet international competition, much non-upgraded bitumen is now sold as a blend of multiple grades of bitumen, conventional crude oil, synthetic crude oil, and condensate in a standardized benchmark product such as [[Western Canadian Select]]. This sour, heavy crude oil blend is designed to have uniform refining characteristics to compete with internationally marketed heavy oils such as [[Petroleum industry in Mexico|Mexican Mayan]] or Arabian [[Dubai Crude]].<ref name=CAPP2015/>

=== Radioactive waste encapsulation matrix ===
Bitumen was used starting in the 1960s as a [[hydrophobic]] matrix aiming to encapsulate [[radioactive waste]] such as medium-activity salts (mainly soluble [[sodium nitrate]] and [[sodium sulfate]]) produced by the reprocessing of [[spent nuclear fuel]]s or radioactive [[sludge]]s from sedimentation ponds.<ref>Rodier, J., Scheidhauer, J., & Malabre, M. (1961). The conditioning of radioactive waste by bitumen (No. CEA-R{{snd}}1992). CEA Marcoule.</ref><ref>Lefillatre, G., Rodier, J., Hullo, R., Cudel, Y., & Rodi, L. (1969). Use of a thin-film evaporator for bitumen coating of radioactive concentrates (No. CEA-R{{snd}}3742). CEA Marcoule.</ref> Bituminised radioactive waste containing highly [[radiotoxic]] [[ionizing radiation#Alpha particles|alpha-emitting]] [[Transuranium element|transuranic element]]s from nuclear reprocessing plants have been produced at industrial scale in France, Belgium and Japan, but this type of waste conditioning has been abandoned because operational safety issues (risks of fire, as occurred in a bituminisation plant at Tokai Works in Japan)<ref>Sato, Y., Miura, A., Kato, Y., Suzuki, H., Shigetome, Y., Koyama, T., ... & Yamanouchi, T. (2000). Study on the cause of the fire and explosion incident at Bituminization Demonstration Facility of PNC Tokai Works. In Nuclear waste: from research to industrial maturity. International conference (pp. 179–190).</ref><ref>Okada, K., Nur, R. M., & Fujii, Y. (1999). The formation of explosive compounds in bitumen/nitrate mixtures. Journal of hazardous materials, 69(3), 245–256.</ref> and long-term stability problems related to their [[Deep geological repository|geological disposal]] in deep rock formations. One of the main problems is the swelling of bitumen exposed to radiation and to water. Bitumen swelling is first induced by radiation because of the presence of [[hydrogen]] gas bubbles generated by alpha and gamma [[radiolysis]].<ref>Johnson, D.I., Hitchon, J.W., & Phillips, D.C. (1986). Further observations of the swelling of bitumens and simulated bitumen wasteforms during γ-irradiation (No. AERE-R{{snd}}12292). UKAEA Harwell Lab. Materials Development Division.</ref><ref>Phillips, D. C., Hitchon, J. W., Johnson, D. I., & Matthews, J. R. (1984). The radiation swelling of bitumens and bitumenised wastes. Journal of nuclear materials, 125(2), 202–218.</ref> A second mechanism is the matrix swelling when the encapsulated [[hygroscopic]] salts exposed to water or moisture start to rehydrate and to dissolve. The high concentration of salt in the pore solution inside the bituminised matrix is then responsible for [[osmosis|osmotic]] effects inside the bituminised matrix. The water moves in the direction of the concentrated salts, the bitumen acting as a [[Semipermeable membrane|semi-permeable membrane]]. This also causes the matrix to swell. The swelling pressure due to osmotic effect under constant volume can be as high as 200 bar. If not properly managed, this high pressure can cause fractures in the near field of a disposal gallery of bituminised medium-level waste. When the bituminised matrix has been altered by swelling, encapsulated radionuclides are easily leached by the contact of ground water and released in the geosphere. The high [[ionic strength]] of the concentrated saline solution also favours the migration of radionuclides in clay host rocks. The presence of chemically reactive nitrate can also affect the [[redox]] conditions prevailing in the host rock by establishing oxidizing conditions, preventing the reduction of redox-sensitive radionuclides. Under their higher valences, radionuclides of elements such as [[selenium]], [[technetium]], [[uranium]], [[neptunium]] and [[plutonium]] have a higher solubility and are also often present in water as non-retarded [[anion]]s. This makes the disposal of medium-level bituminised waste very challenging.

Different types of bitumen have been used: blown bitumen (partly oxidized with air oxygen at high temperature after distillation, and harder) and direct distillation bitumen (softer). Blown bitumens like Mexphalte, with a high content of saturated hydrocarbons, are more easily biodegraded by microorganisms than direct distillation bitumen, with a low content of saturated hydrocarbons and a high content of aromatic hydrocarbons.<ref>Ait-Langomazino, N., Sellier, R., Jouquet, G., & Trescinski, M. (1991). Microbial degradation of bitumen. Experientia, 47(6), 533–539.</ref>

Concrete encapsulation of radwaste is presently considered a safer alternative by the [[nuclear industry]] and the waste management organisations.

=== Other uses ===
[[Asphalt shingle|Roofing shingle]]s and [[Asphalt roll roofing|roll roofing]] account for most of the remaining bitumen consumption. Other uses include cattle sprays, fence-post treatments, and waterproofing for fabrics. Bitumen is used to make [[Japan black]], a [[lacquer]] known especially for its use on iron and steel, and it is also used in paint and marker inks by some exterior paint supply companies to increase the weather resistance and permanence of the paint or ink, and to make the color darker.<ref>{{Cite web |title=Bitumen {{!}} Oil Sands, Extraction & Refining {{!}} Britannica |url=https://www.britannica.com/science/bitumen |access-date=23 June 2024 |website=www.britannica.com |language=en}}</ref> Bitumen is also used to seal some alkaline batteries during the manufacturing process. Bitumen is also commonly used as a ''ground'' in the etching process of [[intaglio printmaking]].