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8901
solutions thus have a pH of less than 7. While the Arrhenius concept is useful for describing many reactions, it is also quite limited in its scope. In 1923 chemists Johannes Nicolaus Brønsted and Thomas Martin Lowry independently recognized that acid-base reactions involve the transfer of a proton. A Brønsted-Lowry acid (or simply Brønsted acid) is a species that donates a proton to a Brønsted-Lowry base. Brønsted-Lowry acid-base theory has several advantages over Arrhenius theory. Consider the following reactions of acetic acid (CHCOOH), the organic acid that gives vinegar its characteristic taste: Both theories easily describe the first reaction: CHCOOH
Acid
[ -0.5060689449310303, 0.3478640913963318, 0.3643527925014496, -0.21926461160182953, -0.6454347968101501, 0.04266394302248955, 0.03994771093130112, -0.08486730605363846, 0.10536166280508041, -0.16368888318538666, -0.208475261926651, -0.01758534274995327, -0.40231382846832275, 0.4893247187137...
8902
acts as an Arrhenius acid because it acts as a source of HO when dissolved in water, and it acts as a Brønsted acid by donating a proton to water. In the second example CHCOOH undergoes the same transformation, in this case donating a proton to ammonia (NH), but does not relate to the Arrhenius definition of an acid because the reaction does not produce hydronium. Nevertheless, CHCOOH is both an Arrhenius and a Brønsted-Lowry acid. Brønsted-Lowry theory can be used to describe reactions of molecular compounds in nonaqueous solution or the gas phase. Hydrogen chloride (HCl) and ammonia combine
Acid
[ -0.536539614200592, 0.6261695623397827, 0.4230663776397705, -0.137602761387825, -0.7184925675392151, -0.2524210512638092, 0.07013410329818726, -0.4282363951206207, 0.14530383050441742, 0.016794387251138687, -0.3897571861743927, 0.028222082182765007, -0.5500327348709106, 0.734062910079956, ...
8903
under several different conditions to form ammonium chloride, NHCl. In aqueous solution HCl behaves as hydrochloric acid and exists as hydronium and chloride ions. The following reactions illustrate the limitations of Arrhenius's definition: As with the acetic acid reactions, both definitions work for the first example, where water is the solvent and hydronium ion is formed by the HCl solute. The next two reactions do not involve the formation of ions but are still proton-transfer reactions. In the second reaction hydrogen chloride and ammonia (dissolved in benzene) react to form solid ammonium chloride in a benzene solvent and in the
Acid
[ -0.4538727104663849, 0.47323986887931824, 0.6116176843643188, -0.11769168823957443, -0.4695269763469696, -0.33283185958862305, 0.23125411570072174, -0.5682848691940308, 0.10871996730566025, 0.07370179146528244, -0.3396141529083252, 0.10330547392368317, -0.542114794254303, 0.877633631229400...
8904
third gaseous HCl and NH combine to form the solid. A third, only marginally related concept was proposed in 1923 by Gilbert N. Lewis, which includes reactions with acid-base characteristics that do not involve a proton transfer. A Lewis acid is a species that accepts a pair of electrons from another species; in other words, it is an electron pair acceptor. Brønsted acid-base reactions are proton transfer reactions while Lewis acid-base reactions are electron pair transfers. Many Lewis acids are not Brønsted-Lowry acids. Contrast how the following reactions are described in terms of acid-base chemistry: In the first reaction a
Acid
[ -0.46894940733909607, 0.19056305289268494, 0.3097486197948456, -0.4564366042613983, -0.7644715309143066, -0.16371090710163116, 0.18057937920093536, -0.6310005187988281, 0.1489429771900177, -0.01304331049323082, -0.25594279170036316, -0.056636445224285126, -0.6694926619529724, 0.65632796287...
8905
fluoride ion, F, gives up an electron pair to boron trifluoride to form the product tetrafluoroborate. Fluoride "loses" a pair of valence electrons because the electrons shared in the B—F bond are located in the region of space between the two atomic nuclei and are therefore more distant from the fluoride nucleus than they are in the lone fluoride ion. BF is a Lewis acid because it accepts the electron pair from fluoride. This reaction cannot be described in terms of Brønsted theory because there is no proton transfer. The second reaction can be described using either theory. A proton
Acid
[ -0.3509860336780548, 0.261414110660553, 0.3810080587863922, -0.19992615282535553, -0.8050597906112671, -0.46095916628837585, 0.2614961564540863, -0.273479163646698, 0.35196423530578613, 0.0776524543762207, -0.40873950719833374, -0.08385614305734634, -0.587865948677063, 0.6272167563438416, ...
8906
is transferred from an unspecified Brønsted acid to ammonia, a Brønsted base; alternatively, ammonia acts as a Lewis base and transfers a lone pair of electrons to form a bond with a hydrogen ion. The species that gains the electron pair is the Lewis acid; for example, the oxygen atom in HO gains a pair of electrons when one of the H—O bonds is broken and the electrons shared in the bond become localized on oxygen. Depending on the context, a Lewis acid may also be described as an oxidizer or an electrophile. Organic Brønsted acids, such as acetic, citric,
Acid
[ -0.43094903230667114, 0.4301054775714874, 0.3819758892059326, -0.24656766653060913, -0.650455892086029, -0.23523038625717163, 0.07691176980733871, -0.4193475544452667, 0.020964117720723152, -0.27954167127609253, -0.6155897974967957, 0.001734567922540009, -0.4839511811733246, 0.592430591583...
8907
or oxalic acid, are not Lewis acids. They dissociate in water to produce a Lewis acid, H, but at the same time also yield an equal amount of a Lewis base (acetate, citrate, or oxalate, respectively, for the acids mentioned). Few, if any, of the acids discussed in the following are Lewis acids. Reactions of acids are often generalized in the form HA H + A, where HA represents the acid and A is the conjugate base. This reaction is referred to as protolysis. The protonated form (HA) of an acid is also sometimes referred to as the free acid.
Acid
[ -0.4358906149864197, 0.632882833480835, 0.2517825663089752, -0.23480239510536194, -0.7154529690742493, -0.10709111392498016, 0.3197541832923889, -0.45907947421073914, 0.2203233242034912, -0.30092769861221313, -0.520317018032074, 0.08174070715904236, -0.4780530631542206, 0.5575527548789978,...
8908
Acid-base conjugate pairs differ by one proton, and can be interconverted by the addition or removal of a proton (protonation and deprotonation, respectively). Note that the acid can be the charged species and the conjugate base can be neutral in which case the generalized reaction scheme could be written as HA H + A. In solution there exists an equilibrium between the acid and its conjugate base. The equilibrium constant "K" is an expression of the equilibrium concentrations of the molecules or the ions in solution. Brackets indicate concentration, such that [HO] means "the concentration of HO". The acid dissociation
Acid
[ -0.5096132159233093, 0.512451708316803, 0.3300023674964905, -0.2720799744129181, -0.5982223749160767, -0.1900368183851242, 0.29045403003692627, -0.6150553822517395, 0.10858378559350967, -0.263162761926651, -0.19267532229423523, -0.08984698355197906, -0.5706399083137512, 0.7328868508338928,...
8909
constant "K" is generally used in the context of acid-base reactions. The numerical value of "K" is equal to the product of the concentrations of the products divided by the concentration of the reactants, where the reactant is the acid (HA) and the products are the conjugate base and H. The stronger of two acids will have a higher "K" than the weaker acid; the ratio of hydrogen ions to acid will be higher for the stronger acid as the stronger acid has a greater tendency to lose its proton. Because the range of possible values for "K" spans many
Acid
[ -0.5329363942146301, 0.46242496371269226, 0.30514004826545715, -0.07237344980239868, -0.5383838415145874, 0.1194743886590004, 0.28669682145118713, -0.6308147311210632, 0.2149227410554886, -0.2890951335430145, -0.08684968948364258, 0.027225378900766373, -0.45680147409439087, 0.7951050996780...
8910
orders of magnitude, a more manageable constant, p"K" is more frequently used, where p"K" = −log "K". Stronger acids have a smaller p"K" than weaker acids. Experimentally determined p"K" at 25 °C in aqueous solution are often quoted in textbooks and reference material. In the classical naming system, acids are named according to their anions. That ionic suffix is dropped and replaced with a new suffix (and sometimes prefix), according to the table below. For example, HCl has chloride as its anion, so the -ide suffix makes it take the form hydrochloric acid. In the IUPAC naming system, "aqueous" is
Acid
[ -0.3201703131198883, 0.5952498912811279, 0.03603070601820946, 0.007505140267312527, -0.4900287687778473, -0.19487231969833374, 0.41939541697502136, -0.3088853657245636, 0.0152439521625638, -0.049310315400362015, -0.4730011224746704, 0.014803417026996613, -0.295742005109787, 1.0298042297363...
8911
simply added to the name of the ionic compound. Thus, for hydrogen chloride, the IUPAC name would be aqueous hydrogen chloride. The prefix "hydro-" is added only if the acid is made up of just hydrogen and one other element. Classical naming system: The strength of an acid refers to its ability or tendency to lose a proton. A strong acid is one that completely dissociates in water; in other words, one mole of a strong acid HA dissolves in water yielding one mole of H and one mole of the conjugate base, A, and none of the protonated acid
Acid
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8912
HA. In contrast, a weak acid only partially dissociates and at equilibrium both the acid and the conjugate base are in solution. Examples of strong acids are hydrochloric acid (HCl), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HClO), nitric acid (HNO) and sulfuric acid (HSO). In water each of these essentially ionizes 100%. The stronger an acid is, the more easily it loses a proton, H. Two key factors that contribute to the ease of deprotonation are the polarity of the H—A bond and the size of atom A, which determines the strength of the H—A bond. Acid strengths
Acid
[ -0.4212864339351654, 0.5294279456138611, 0.39519014954566956, -0.003653367981314659, -0.5950456857681274, -0.2842126786708832, 0.28597328066825867, -0.5755742192268372, 0.2622482180595398, -0.3452637791633606, -0.46911904215812683, 0.04996708407998085, -0.36444583535194397, 0.6220434308052...
8913
are also often discussed in terms of the stability of the conjugate base. Stronger acids have a larger "K" and a more negative p"K" than weaker acids. Sulfonic acids, which are organic oxyacids, are a class of strong acids. A common example is toluenesulfonic acid (tosylic acid). Unlike sulfuric acid itself, sulfonic acids can be solids. In fact, polystyrene functionalized into polystyrene sulfonate is a solid strongly acidic plastic that is filterable. Superacids are acids stronger than 100% sulfuric acid. Examples of superacids are fluoroantimonic acid, magic acid and perchloric acid. Superacids can permanently protonate water to give ionic, crystalline
Acid
[ -0.2134053111076355, 0.29083696007728577, 0.2960367500782013, 0.1375555694103241, -0.5837246775627136, -0.16402603685855865, 0.26271766424179077, -0.10441769659519196, 0.18240049481391907, -0.36232781410217285, -0.6999717354774475, 0.2837308645248413, -0.6791555285453796, 0.566941380500793...
8914
hydronium "salts". They can also quantitatively stabilize carbocations. While "K" measures the strength of an acid compound, the strength of an aqueous acid solution is measured by pH, which is an indication of the concentration of hydronium in the solution. The pH of a simple solution of an acid compound in water is determined by the dilution of the compound and the compound's "K". Monoprotic acids, also known as monobasic acids, are those acids that are able to donate one proton per molecule during the process of dissociation (sometimes called ionization) as shown below (symbolized by HA): Common examples of
Acid
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8915
monoprotic acids in mineral acids include hydrochloric acid (HCl) and nitric acid (HNO). On the other hand, for organic acids the term mainly indicates the presence of one carboxylic acid group and sometimes these acids are known as monocarboxylic acid. Examples in organic acids include formic acid (HCOOH), acetic acid (CHCOOH) and benzoic acid (CHCOOH). Polyprotic acids, also known as polybasic acids, are able to donate more than one proton per acid molecule, in contrast to monoprotic acids that only donate one proton per molecule. Specific types of polyprotic acids have more specific names, such as diprotic (or dibasic) acid
Acid
[ -0.12639155983924866, 0.5533914566040039, 0.17682825028896332, 0.20127537846565247, -0.5307704210281372, 0.01858583092689514, -0.0055862413719296455, -0.28014007210731506, 0.020368076860904694, 0.030893666669726372, -0.6454618573188782, -0.14159975945949554, -0.6035651564598083, 0.55084294...
8916
(two potential protons to donate), and triprotic (or tribasic) acid (three potential protons to donate). A diprotic acid (here symbolized by HA) can undergo one or two dissociations depending on the pH. Each dissociation has its own dissociation constant, K and K. The first dissociation constant is typically greater than the second; i.e., "K" > "K". For example, sulfuric acid (HSO) can donate one proton to form the bisulfate anion (HSO), for which "K" is very large; then it can donate a second proton to form the sulfate anion (SO), wherein the "K" is intermediate strength. The large "K" for
Acid
[ -0.30275341868400574, 0.44545429944992065, 0.15555141866207123, -0.018331194296479225, -0.775981068611145, -0.11952738463878632, 0.35483548045158386, -0.42569833993911743, 0.08279254287481308, -0.25529223680496216, -0.416351318359375, -0.2425866574048996, -0.46014198660850525, 0.5659535527...
8917
the first dissociation makes sulfuric a strong acid. In a similar manner, the weak unstable carbonic acid can lose one proton to form bicarbonate anion and lose a second to form carbonate anion (CO). Both "K" values are small, but "K" > "K" . A triprotic acid (HA) can undergo one, two, or three dissociations and has three dissociation constants, where "K" > "K" > "K". An inorganic example of a triprotic acid is orthophosphoric acid (HPO), usually just called phosphoric acid. All three protons can be successively lost to yield HPO, then HPO, and finally PO, the orthophosphate ion,
Acid
[ -0.5372804999351501, 0.6123731732368469, 0.02976381406188011, 0.06846798211336136, -0.6788314580917358, -0.08695261925458908, 0.19804702699184418, -0.3440336585044861, 0.1590222418308258, -0.21260711550712585, -0.37170547246932983, -0.13073310256004333, -0.580562174320221, 0.52777218818664...
8918
usually just called phosphate. Even though the positions of the three protons on the original phosphoric acid molecule are equivalent, the successive "K" values differ since it is energetically less favorable to lose a proton if the conjugate base is more negatively charged. An organic example of a triprotic acid is citric acid, which can successively lose three protons to finally form the citrate ion. Although the subsequent loss of each hydrogen ion is less favorable, all of the conjugate bases are present in solution. The fractional concentration, "α" (alpha), for each species can be calculated. For example, a generic
Acid
[ -0.42030444741249084, 0.45676082372665405, 0.09302389621734619, 0.1277925819158554, -0.5168456435203552, -0.17172835767269135, 0.447563111782074, -0.26322275400161743, -0.04693809524178505, -0.1512659192085266, -0.3643772006034851, -0.08169489353895187, -0.6033264398574829, 0.6029185056686...
8919
diprotic acid will generate 3 species in solution: HA, HA, and A. The fractional concentrations can be calculated as below when given either the pH (which can be converted to the [H]) or the concentrations of the acid with all its conjugate bases: A plot of these fractional concentrations against pH, for given "K" and "K", is known as a Bjerrum plot. A pattern is observed in the above equations and can be expanded to the general "n" -protic acid that has been deprotonated "i" -times: \alpha_{\ce H_{n-i} A^{i-} }= Acid An acid is a molecule or ion capable of
Acid
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8920
Asphalt Asphalt, also known as bitumen (, ), is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient Greek ἄσφαλτος "ásphaltos". The primary use (70%) of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other main uses are for bituminous waterproofing products, including production of roofing
Asphalt
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8921
felt and for sealing flat roofs. The terms "asphalt" and "bitumen" are often used interchangeably to mean both natural and manufactured forms of the substance. In American English, "asphalt" (or "asphalt cement") is commonly used for a refined residue from the distillation process of selected crude oils. Outside the United States, the product is often called "bitumen", and geologists worldwide often prefer the term for the naturally occurring variety. Common colloquial usage often refers to various forms of asphalt as "tar", as in the name of the La Brea Tar Pits. Naturally occurring asphalt is sometimes specified by the term
Asphalt
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8922
"crude bitumen". Its viscosity is similar to that of cold molasses while the material obtained from the fractional distillation of crude oil boiling at is sometimes referred to as "refined bitumen". The Canadian province of Alberta has most of the world's reserves of natural asphalt in the Athabasca oil sands, which cover , an area larger than England. The word "asphalt" is derived from the late Middle English, in turn from French "asphalte", based on Late Latin "asphalton", "asphaltum", which is the latinisation of the Greek ἄσφαλτος ("ásphaltos", "ásphalton"), a word meaning "asphalt/bitumen/pitch", which perhaps derives from ἀ-, "without" and
Asphalt
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8923
σφάλλω ("sfallō"), "make fall". The first use of asphalt by the ancients was in the nature of a cement for securing or joining together various objects, and it thus seems likely that the name itself was expressive of this application. Specifically, Herodotus mentioned that bitumen was brought to Babylon to build its gigantic fortification wall. From the Greek, the word passed into late Latin, and thence into French ("asphalte") and English ("asphaltum" and "asphalt"). In French, the term "asphalte" is used for naturally occurring asphalt-soaked limestone deposits, and for specialised manufactured products with fewer voids or greater bitumen content than
Asphalt
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8924
the "asphaltic concrete" used to pave roads. The expression "bitumen" originated in the Sanskrit words "jatu", meaning "pitch", and "jatu-krit", meaning "pitch creating" or "pitch producing" (referring to coniferous or resinous trees). The Latin equivalent is claimed by some to be originally "gwitu-men" (pertaining to pitch), and by others, "pixtumens" (exuding or bubbling pitch), which was subsequently shortened to "bitumen", thence passing via French into English. From the same root is derived the Anglo-Saxon word "cwidu" (mastix), the German word "Kitt" (cement or mastic) and the old Norse word "kvada". In British English, "bitumen" is used instead of "asphalt". The
Asphalt
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8925
word "asphalt" is instead used to refer to asphalt concrete, a mixture of construction aggregate and asphalt itself (also called "tarmac" in common parlance). Bitumen mixed with clay was usually called "asphaltum", but the term is less commonly used today. In Australian English, the word "asphalt" is used to describe a mix of construction aggregate. "Bitumen" refers to the liquid derived from the heavy-residues from crude oil distillation. In American English, "asphalt" is equivalent to the British "bitumen". However, "asphalt" is also commonly used as a shortened form of "asphalt concrete" (therefore equivalent to the British "asphalt" or "tarmac"). In
Asphalt
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8926
Canadian English, the word "bitumen" is used to refer to the vast Canadian deposits of extremely heavy crude oil, while "asphalt" is used for the oil refinery product. Diluted bitumen (diluted with naphtha to make it flow in pipelines) is known as "dilbit" in the Canadian petroleum industry, while bitumen "upgraded" to synthetic crude oil is known as "syncrude", and syncrude blended with bitumen is called "synbit". "Bitumen" is still the preferred geological term for naturally occurring deposits of the solid or semi-solid form of petroleum. "Bituminous rock" is a form of sandstone impregnated with bitumen. The oil sands of
Asphalt
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8927
Alberta, Canada are a similar material. Neither of the terms "asphalt" or "bitumen" should be confused with tar or coal tars. Tar is the thick liquid product of the dry distillation and pyrolysis of organic hydrocarbons primarily sourced from vegetation masses, whether fossilized as with coal, or freshly harvested. The majority of bitumen, on the other hand, was formed naturally when vast quantities of organic animal materials were deposited by water and buried hundreds of metres deep at the diagenetic point, where the disorganized fatty hydrocarbon molecules joined together in long chains in the absence of oxygen. Bitumen occurs as
Asphalt
[ 0.5037545561790466, 0.22519618272781372, -0.38606491684913635, 0.33936864137649536, 0.03414289280772209, 0.12762796878814697, -0.20165757834911346, 0.7036393284797668, 0.5402317643165588, -0.37580323219299316, -0.3836655616760254, 0.8316201567649841, 0.1950002908706665, 0.5071096420288086,...
8928
a solid or highly viscous liquid. It may even be mixed in with coal deposits. Bitumen, and coal using the Bergius process, can be refined into petrols such as gasoline, and bitumen may be distilled into tar, not the other way around. The components of asphalt include four main classes of compounds: The naphthene aromatics and polar aromatics are typically the majority components. Most natural bitumens also contain organosulfur compounds, resulting in an overall sulfur content of up to 4%. Nickel and vanadium are found at <10 parts per million, as is typical of some petroleum. The substance is soluble
Asphalt
[ 0.282885879278183, 0.3027856647968292, -0.2503557801246643, 0.2723100185394287, -0.13032205402851105, -0.005185964982956648, -0.07369320839643478, 0.38987845182418823, 0.6202852129936218, -0.5172458291053772, -0.49219661951065063, 0.9854487776756287, 0.16505107283592224, 0.2783201634883880...
8929
in carbon disulfide. It is commonly modelled as a colloid, with asphaltenes as the dispersed phase and maltenes as the continuous phase. "It is almost impossible to separate and identify all the different molecules of asphalt, because the number of molecules with different chemical structure is extremely large". Asphalt may be confused with coal tar, which is a visually similar black, thermoplastic material produced by the destructive distillation of coal. During the early and mid-20th century, when town gas was produced, coal tar was a readily available byproduct and extensively used as the binder for road aggregates. The addition of
Asphalt
[ 0.2959597110748291, 0.34218376874923706, -0.20579393208026886, 0.004154070746153593, -0.03838994726538658, -0.0124330073595047, -0.10457351058721542, 0.6910618543624878, 0.40515145659446716, -0.6343206167221069, -0.2663224935531616, 0.8606937527656555, -0.04132799804210663, 0.5519037246704...
8930
coal tar to macadam roads led to the word "tarmac", which is now used in common parlance to refer to road-making materials. However, since the 1970s, when natural gas succeeded town gas, asphalt has completely overtaken the use of coal tar in these applications. Other examples of this confusion include the La Brea Tar Pits and the Canadian oil sands, both of which actually contain natural bitumen rather than tar. "Pitch" is another term sometimes informally used at times to refer to asphalt, as in Pitch Lake. For economic and other reasons, asphalt is sometimes sold combined with other materials,
Asphalt
[ 0.4038497805595398, 0.15033763647079468, -0.16788841784000397, 0.25953444838523865, 0.11117176711559296, -0.010554871521890163, -0.1037312000989914, 0.965819239616394, 0.31176286935806274, -0.569661557674408, -0.09480535984039307, 0.7155099511146545, 0.19506211578845978, 0.5044392347335815...
8931
often without being labeled as anything other than simply "asphalt". Of particular note, in the 21st century, is the use of re-refined engine oil bottoms -- "REOB" or "REOBs"—the residue of recycled autmotive engine oil, collected from the bottoms of re-refining vacuum distillation towers. It contains the various non-refined elements and compounds in recycled engine oil, leftover from the re-refining process—both additives to the original oil, and materials accumulating from its circulation in the engine (typically iron and copper). Some research has indicated a correlation between this contamination of asphalt and poorer-performing pavement. The majority of asphalt used commercially is
Asphalt
[ 0.4631032943725586, 0.4772130846977234, -0.1750486046075821, 0.16734999418258667, 0.28249427676200867, 0.1547544300556183, -0.2705520987510681, 0.33350926637649536, 0.2820681929588318, -0.49295833706855774, -0.19336433708667755, 0.8794727325439453, 0.26383069157600403, 0.20826034247875214,...
8932
obtained from petroleum. Nonetheless, large amounts of asphalt occur in concentrated form in nature. Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae (diatoms) and other once-living things. These remains were deposited in the mud on the bottom of the ocean or lake where the organisms lived. Under the heat (above 50 °C) and pressure of burial deep in the earth, the remains were transformed into materials such as bitumen, kerogen, or petroleum. Natural deposits of bitumen include lakes such as the Pitch Lake in Trinidad and Tobago and Lake Bermudez in Venezuela. Natural seeps
Asphalt
[ 0.36848798394203186, 0.10334771126508713, -0.2179076373577118, 0.6337379217147827, 0.32591450214385986, 0.10379567742347717, -0.1670996993780136, 0.8070441484451294, 0.3623186945915222, -0.46531128883361816, -0.20889253914356232, 0.9692063331604004, 0.2801620364189148, 0.25205668807029724,...
8933
occur in the La Brea Tar Pits and in the Dead Sea. Bitumen also occurs in unconsolidated sandstones known as "oil sands" in Alberta, Canada, and the similar "tar sands" in Utah, US. The Canadian province of Alberta has most of the world's reserves, in three huge deposits covering , an area larger than England or New York state. These bituminous sands contain of commercially established oil reserves, giving Canada the third largest oil reserves in the world. Although historically it was used without refining to pave roads, nearly all of the output is now used as raw material for
Asphalt
[ 0.47498366236686707, 0.19061096012592316, -0.13610628247261047, 0.4804390072822571, 0.24962478876113892, 0.2039189487695694, -0.22630833089351654, 0.9550706744194031, 0.380672425031662, -0.5776816606521606, -0.23314271867275238, 0.8563121557235718, 0.5460529327392578, 0.3002375364303589, ...
8934
oil refineries in Canada and the United States. The world's largest deposit of natural bitumen, known as the Athabasca oil sands, is located in the McMurray Formation of Northern Alberta. This formation is from the early Cretaceous, and is composed of numerous lenses of oil-bearing sand with up to 20% oil. Isotopic studies show the oil deposits to be about 110 million years old. Two smaller but still very large formations occur in the Peace River oil sands and the Cold Lake oil sands, to the west and southeast of the Athabasca oil sands, respectively. Of the Alberta deposits, only
Asphalt
[ 0.572688102722168, 0.14338766038417816, 0.02121264860033989, 0.357887327671051, 0.3243487775325775, 0.3387289047241211, -0.31479114294052124, 0.9608184695243835, 0.3131215572357178, -0.49699559807777405, -0.15217654407024384, 0.8555831909179688, 0.4255172312259674, 0.3138723075389862, 0....
8935
parts of the Athabasca oil sands are shallow enough to be suitable for surface mining. The other 80% has to be produced by oil wells using enhanced oil recovery techniques like steam-assisted gravity drainage. Much smaller heavy oil or bitumen deposits also occur in the Uinta Basin in Utah, US. The Tar Sand Triangle deposit, for example, is roughly 6% bitumen. Bitumen may occur in hydrothermal veins. An example of this is within the Uinta Basin of Utah, in the US, where there is a swarm of laterally and vertically extensive veins composed of a solid hydrocarbon termed Gilsonite. These
Asphalt
[ 0.5094289183616638, 0.18900009989738464, -0.06050056591629982, 0.5964517593383789, 0.31607887148857117, 0.04553765431046486, -0.20424339175224304, 0.7247712016105652, 0.4088868796825409, -0.5391442775726318, -0.10994274169206619, 0.8228505849838257, 0.42768213152885437, 0.25257062911987305...
8936
veins formed by the polymerization and solidification of hydrocarbons that were mobilized from the deeper oil shales of the Green River Formation during burial and diagenesis. Bitumen is similar to the organic matter in carbonaceous meteorites. However, detailed studies have shown these materials to be distinct. The vast Alberta bitumen resources are considered to have started out as living material from marine plants and animals, mainly algae, that died millions of years ago when an ancient ocean covered Alberta. They were covered by mud, buried deeply over time, and gently cooked into oil by geothermal heat at a temperature of
Asphalt
[ 0.5610717535018921, 0.3103031516075134, -0.12530027329921722, 0.589203953742981, 0.1070551797747612, 0.04776560515165329, -0.08553612977266312, 0.9130469560623169, 0.5303237438201904, -0.5455850958824158, 0.1266990602016449, 0.8010286688804626, 0.46934765577316284, 0.24985775351524353, -...
8937
. Due to pressure from the rising of the Rocky Mountains in southwestern Alberta, 80 to 55 million years ago, the oil was driven northeast hundreds of kilometres and trapped into underground sand deposits left behind by ancient river beds and ocean beaches, thus forming the oil sands. The use of natural bitumen for waterproofing, and as an adhesive dates at least to the fifth millennium BC, with a crop storage basket discovered in Mehrgarh, of the Indus Valley Civilization, lined with it. By the 3rd millennia BC refined rock asphalt was in use, in the region, and was used
Asphalt
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8938
to waterproof the Great Bath, Mohenjo-daro. In the ancient Middle East, the Sumerians used natural bitumen deposits for mortar between bricks and stones, to cement parts of carvings, such as eyes, into place, for ship caulking, and for waterproofing. The Greek historian Herodotus said hot bitumen was used as mortar in the walls of Babylon. The long Euphrates Tunnel beneath the river Euphrates at Babylon in the time of Queen Semiramis (ca. 800 BC) was reportedly constructed of burnt bricks covered with bitumen as a waterproofing agent. Bitumen was used by ancient Egyptians to embalm mummies. The Persian word for
Asphalt
[ 0.3007734715938568, 0.2268979251384735, -0.46606677770614624, 0.41602200269699097, -0.06660725921392441, 0.4324158728122711, -0.21378017961978912, 0.7015410661697388, 0.09072863310575485, -0.6085151433944702, -0.06481947749853134, 0.6606686115264893, 0.2946242094039917, 0.17947721481323242...
8939
asphalt is "moom", which is related to the English word mummy. The Egyptians' primary source of bitumen was the Dead Sea, which the Romans knew as "Palus Asphaltites" (Asphalt Lake). Approximately 40 AD, Dioscorides described the Dead Sea material as "Judaicum bitumen", and noted other places in the region where it could be found. The Sidon bitumen is thought to refer to material found at Hasbeya. Pliny refers also to bitumen being found in Epirus. It was a valuable strategic resource, the object of the first known battle for a hydrocarbon deposit—between the Seleucids and the Nabateans in 312 BC.
Asphalt
[ 0.2783317565917969, 0.0756259337067604, -0.2854982912540436, 0.2687298357486725, 0.1257213056087494, 0.4534435272216797, -0.5344880819320679, 0.71978360414505, 0.39658722281455994, -0.6192683577537537, -0.018476124852895737, 0.6703912615776062, 0.1294858604669571, 0.44835081696510315, 0....
8940
In the ancient Far East, natural bitumen was slowly boiled to get rid of the higher fractions, leaving a thermoplastic material of higher molecular weight that when layered on objects became quite hard upon cooling. This was used to cover objects that needed waterproofing, such as scabbards and other items. Statuettes of household deities were also cast with this type of material in Japan, and probably also in China. In North America, archaeological recovery has indicated bitumen was sometimes used to adhere stone projectile points to wooden shafts. In Canada, aboriginal people used bitumen seeping out of the banks of
Asphalt
[ 0.35346463322639465, 0.1841960996389389, -0.2742812931537628, 0.6518716812133789, -0.2598586678504944, 0.09387015551328659, -0.058607522398233414, 0.60499507188797, 0.5404156446456909, -0.49693071842193604, -0.05205821245908737, 0.5780344605445862, 0.3710370361804962, -0.013037259690463543...
8941
the Athabasca and other rivers to waterproof birch bark canoes, and also heated it in smudge pots to ward off mosquitoes in the summer. In 1553, Pierre Belon described in his work "Observations" that "pissasphalto", a mixture of pitch and bitumen, was used in the Republic of Ragusa (now Dubrovnik, Croatia) for tarring of ships. An 1838 edition of "Mechanics Magazine" cites an early use of asphalt in France. A pamphlet dated 1621, by "a certain Monsieur d'Eyrinys, states that he had discovered the existence (of asphaltum) in large quantities in the vicinity of Neufchatel", and that he proposed to
Asphalt
[ 0.15878036618232727, 0.09299105405807495, -0.33242282271385193, 0.2301792949438095, 0.19657884538173676, 0.329066663980484, 0.05067446827888489, 0.6284996867179871, 0.3161173462867737, -0.4636954665184021, 0.20610731840133667, 0.6192660927772522, 0.04105781763792038, -0.06148950755596161, ...
8942
use it in a variety of ways – "principally in the construction of air-proof granaries, and in protecting, by means of the arches, the water-courses in the city of Paris from the intrusion of dirt and filth", which at that time made the water unusable. "He expatiates also on the excellence of this material for forming level and durable terraces" in palaces, "the notion of forming such terraces in the streets not one likely to cross the brain of a Parisian of that generation". But the substance was generally neglected in France until the revolution of 1830. In the 1830s
Asphalt
[ 0.3016084134578705, 0.32562926411628723, -0.25408992171287537, 0.31036826968193054, -0.07271469384431839, -0.03073016367852688, -0.31038787961006165, 0.5733453035354614, 0.31687524914741516, -0.7509280443191528, 0.1179034411907196, 0.8956512808799744, 0.2965415120124817, 0.2859176099300384...
8943
there was a surge of interest, and asphalt became widely used "for pavements, flat roofs, and the lining of cisterns, and in England, some use of it had been made of it for similar purposes". Its rise in Europe was "a sudden phenomenon", after natural deposits were found "in France at Osbann (Bas-Rhin), the Parc (Ain) and the Puy-de-la-Poix (Puy-de-Dôme)", although it could also be made artificially. One of the earliest uses in France was the laying of about 24,000 square yards of Seyssel asphalt at the Place de la Concorde in 1835. Among the earlier uses of bitumen in
Asphalt
[ 0.3450135588645935, 0.031901709735393524, -0.06837505102157593, 0.12090889364480972, 0.14917567372322083, 0.4248822331428528, -0.23219865560531616, 0.6633045077323914, 0.3017332851886749, -0.7480960488319397, -0.021171927452087402, 0.6008315682411194, 0.20430585741996765, 0.372555822134017...
8944
the United Kingdom was for etching. William Salmon's "Polygraphice" (1673) provides a recipe for varnish used in etching, consisting of three ounces of virgin wax, two ounces of mastic, and one ounce of asphaltum. By the fifth edition in 1685, he had included more asphaltum recipes from other sources. The first British patent for the use of asphalt was "Cassell's patent asphalte or bitumen" in 1834. Then on 25 November 1837, Richard Tappin Claridge patented the use of Seyssel asphalt (patent #7849), for use in asphalte pavement, having seen it employed in France and Belgium when visiting with Frederick Walter
Asphalt
[ 0.21915292739868164, 0.1365354061126709, -0.14315998554229736, -0.16838327050209045, -0.05344738811254501, 0.495187371969223, -0.18138360977172852, 0.5827032923698425, 0.4157349467277527, -0.410394549369812, -0.014894921332597733, 0.7922558188438416, 0.14112278819084167, 0.3201879560947418...
8945
Simms, who worked with him on the introduction of asphalt to Britain. Dr T. Lamb Phipson writes that his father, Samuel Ryland Phipson, a friend of Claridge, was also "instrumental in introducing the asphalte pavement (in 1836)". Indeed, mastic pavements had been previously employed at Vauxhall by a competitor of Claridge, but without success. Claridge obtained a patent in Scotland on 27 March 1838, and obtained a patent in Ireland on 23 April 1838. In 1851, extensions for the 1837 patent and for both 1838 patents were sought by the trustees of a company previously formed by Claridge. "Claridge's Patent
Asphalt
[ 0.1862683743238449, 0.39376604557037354, 0.06808248907327652, -0.2874249219894409, -0.085444875061512, 0.4493545591831207, -0.2434573918581009, 0.43473386764526367, 0.2481081783771515, -0.39576226472854614, 0.11717952787876129, 0.6328679919242859, 0.16489802300930023, 0.3988144099712372, ...
8946
Asphalte Company"—formed in 1838 for the purpose of introducing to Britain "Asphalte in its natural state from the mine at Pyrimont Seysell in France",—"laid one of the first asphalt pavements in Whitehall". Trials were made of the pavement in 1838 on the footway in Whitehall, the stable at Knightsbridge Barracks, "and subsequently on the space at the bottom of the steps leading from Waterloo Place to St. James Park". "The formation in 1838 of Claridge's Patent Asphalte Company (with a distinguished list of aristocratic patrons, and Marc and Isambard Brunel as, respectively, a trustee and consulting engineer), gave an enormous
Asphalt
[ 0.3030460774898529, 0.32367631793022156, 0.04577205702662468, -0.24461126327514648, 0.07454876601696014, 0.4423827528953552, -0.4211317002773285, 0.4080662131309509, 0.47459056973457336, -0.3822524845600128, -0.0933249294757843, 0.6535183787345886, 0.3118393123149872, 0.49276527762413025, ...
8947
impetus to the development of a British asphalt industry". "By the end of 1838, at least two other companies, Robinson's and the Bastenne company, were in production", with asphalt being laid as paving at Brighton, Herne Bay, Canterbury, Kensington, the Strand, and a large floor area in Bunhill-row, while meantime Claridge's Whitehall paving "continue(d) in good order". In 1838, there was a flurry of entrepreneurial activity involving asphalt, which had uses beyond paving. For example, asphalt could also be used for flooring, damp proofing in buildings, and for waterproofing of various types of pools and baths, both of which were
Asphalt
[ 0.45318520069122314, 0.08041476458311081, 0.12459895014762878, -0.2010553926229477, 0.09496702253818512, 0.26614540815353394, -0.16964949667453766, 0.373452365398407, -0.03877021372318268, -0.7473049759864807, 0.017588011920452118, 0.4925145208835602, 0.17893743515014648, 0.290332198143005...
8948
also proliferating in the 19th century. On the London stockmarket, there were various claims as to the exclusivity of asphalt quality from France, Germany and England. And numerous patents were granted in France, with similar numbers of patent applications being denied in England due to their similarity to each other. In England, "Claridge's was the type most used in the 1840s and 50s". In 1914, Claridge's Company entered into a joint venture to produce tar-bound macadam, with materials manufactured through a subsidiary company called Clarmac Roads Ltd. Two products resulted, namely "Clarmac", and "Clarphalte", with the former being manufactured by
Asphalt
[ 0.4011489450931549, 0.07946065813302994, 0.02224867232143879, 0.13403581082820892, -0.17721755802631378, 0.17462722957134247, -0.22465230524539948, 0.6585438251495361, 0.336175799369812, -0.1613810658454895, 0.021947095170617104, 0.780846357345581, 0.08868542313575745, 0.6304313540458679, ...
8949
Clarmac Roads and the latter by Claridge's Patent Asphalte Co., although "Clarmac" was more widely used. However, the First World War ruined the Clarmac Company, which entered into liquidation in 1915. The failure of Clarmac Roads Ltd had a flow-on effect to Claridge's Company, which was itself compulsorily wound up, ceasing operations in 1917, having invested a substantial amount of funds into the new venture, both at the outset and in a subsequent attempt to save the Clarmac Company. The first use of bitumen in the New World was by indigenous peoples. On the west coast, as early as the
Asphalt
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8950
13th century, the Tongva, Luiseño and Chumash peoples collected the naturally occurring bitumen that seeped to the surface above underlying petroleum deposits. All three groups used the substance as an adhesive. It is found on many different artifacts of tools and ceremonial items. For example, it was used on rattles to adhere gourds or turtle shells to rattle handles. It was also used in decorations. Small round shell beads were often set in asphaltum to provide decorations. It was used as a sealant on baskets to make them watertight for carrying water, possibly poisoning those who drank the water. Asphalt
Asphalt
[ 0.20971156656742096, 0.25925907492637634, -0.24021312594413757, 0.41249462962150574, -0.07589530199766159, -0.0476393960416317, 0.050150804221630096, 0.6954410076141357, 0.5250287055969238, -0.5530168414115906, 0.2504391074180603, 0.8222967386245728, 0.17755523324012756, 0.1688860207796096...
8951
was used also to seal the planks on ocean-going canoes. Asphalt was first used to pave streets in the 1870s. At first naturally occurring "bituminous rock" was used, such as at Ritchie Mines in Macfarlan in Ritchie County, West Virginia from 1852 to 1873. In 1876, asphalt-based paving was used to pave Pennsylvania Avenue in Washington DC, in time for the celebration of the national centennial. In the horse-drawn era, streets were unpaved and covered with dirt or gravel. However, that produced uneven wear, opened new hazards for pedestrians and made for dangerous potholes for bicycles and for motor vehicles.
Asphalt
[ 0.27542930841445923, 0.04561280459165573, -0.054747872054576874, 0.2958516478538513, -0.022339563816785812, 0.28709903359413147, -0.09260036051273346, 0.7601298689842224, 0.2253924161195755, -0.8040439486503601, 0.16103366017341614, 0.5313524603843689, -0.010360904037952423, 0.299817949533...
8952
Manhattan alone had 130,000 horses in 1900, pulling streetcars, wagons, and carriages, and leaving their waste behind. They were not fast, and pedestrians could dodge and scramble their way across the crowded streets. Small towns continued to rely on dirt and gravel, but larger cities wanted much better streets. They looked to wood or granite blocks by the 1850s. In 1890, a third of Chicago's 2000 miles of streets were paved, chiefly with wooden blocks, which gave better traction than mud. Brick surfacing was a good compromise, but even better was asphalt paving, which was easy to install and to
Asphalt
[ 0.1555120199918747, -0.08127708733081818, -0.04177643358707428, 0.3672805428504944, -0.5105581879615784, 0.23905475437641144, -0.0672241821885109, 0.6487342119216919, 0.18520942330360413, -0.8809041380882263, 0.28354859352111816, 0.3711518943309784, -0.2189209908246994, 0.22455479204654694...
8953
cut through to get at sewers. With London and Paris serving as models, Washington laid 400,000 square yards of asphalt paving by 1882; it became the model for Buffalo, Philadelphia and elsewhere. By the end of the century, American cities boasted 30 million square yards of asphalt paving, well ahead of brick. The streets became faster and more dangerous so electric traffic lights were installed. Electric trolleys (at 12 miles per hour) became the main transportation service for middle class shoppers and office workers until they bought automobiles after 1945 and commuted from more distant suburbs in privacy and comfort
Asphalt
[ 0.2769155502319336, 0.015619429759681225, 0.045035287737846375, 0.36850208044052124, -0.1682651787996292, 0.4986405372619629, -0.06082133576273918, 0.5562607645988464, 0.026412570849061012, -0.9113991856575012, 0.19298426806926727, 0.3544037342071533, -0.10971541702747345, 0.19280208647251...
8954
on asphalt highways. Canada has the world's largest deposit of natural bitumen in the Athabasca oil sands, and Canadian First Nations along the Athabasca River had long used it to waterproof their canoes. In 1719, a Cree named Wa-Pa-Su brought a sample for trade to Henry Kelsey of the Hudson's Bay Company, who was the first recorded European to see it. However, it wasn't until 1787 that fur trader and explorer Alexander MacKenzie saw the Athabasca oil sands and said, "At about 24 miles from the fork (of the Athabasca and Clearwater Rivers) are some bituminous fountains into which a
Asphalt
[ 0.3471101224422455, 0.3565232753753662, -0.18408194184303284, 0.5719721913337708, 0.1297949105501175, 0.27788034081459045, -0.04585784301161766, 0.8884631395339966, 0.3124130368232727, -0.47453656792640686, 0.18735671043395996, 0.6246299147605896, 0.366902619600296, 0.11766666173934937, ...
8955
pole of 20 feet long may be inserted without the least resistance." The value of the deposit was obvious from the start, but the means of extracting the bitumen was not. The nearest town, Fort McMurray, Alberta, was a small fur trading post, other markets were far away, and transportation costs were too high to ship the raw bituminous sand for paving. In 1915, Sidney Ells of the Federal Mines Branch experimented with separation techniques and used the product to pave 600 feet of road in Edmonton, Alberta. Other roads in Alberta were paved with material extracted from oil sands,
Asphalt
[ 0.5398615598678589, 0.22479760646820068, 0.08071769773960114, 0.4169614613056183, -0.16675223410129547, 0.2662511467933655, -0.32851383090019226, 0.5701097249984741, 0.4395250976085663, -0.7721753120422363, 0.166249617934227, 0.355682909488678, 0.36660560965538025, 0.24569527804851532, 0...
8956
but it was generally not economic. During the 1920s Dr. Karl A. Clark of the Alberta Research Council patented a hot water oil separation process and entrepreneur Robert C. Fitzsimmons built the Bitumount oil separation plant, which between 1925 and 1958 produced up to per day of bitumen using Dr. Clark's method. Most of the bitumen was used for waterproofing roofs, but other uses included fuels, lubrication oils, printers ink, medicines, rust- and acid-proof paints, fireproof roofing, street paving, patent leather, and fence post preservatives. Eventually Fitzsimmons ran out of money and the plant was taken over by the Alberta
Asphalt
[ 0.515113353729248, 0.2539154291152954, -0.12212387472391129, 0.41036704182624817, -0.09084838628768921, 0.2638442814350128, -0.28618520498275757, 0.5160816311836243, 0.48154425621032715, -0.2711857557296753, -0.029438521713018417, 0.718806803226471, 0.20904214680194855, 0.23493964970111847...
8957
government. Today the Bitumount plant is a Provincial Historic Site. Bitumen was used in early photographic technology. In 1826 or 1827, it was used by French scientist Joseph Nicéphore Niépce to make the oldest surviving photograph from nature. The bitumen was thinly coated onto a pewter plate which was then exposed in a camera. Exposure to light hardened the bitumen and made it insoluble, so that when it was subsequently rinsed with a solvent only the sufficiently light-struck areas remained. Many hours of exposure in the camera were required, making bitumen impractical for ordinary photography, but from the 1850s to
Asphalt
[ 0.5299100279808044, 0.30503708124160767, -0.48749038577079773, 0.5144438147544861, 0.052301716059446335, 0.27057650685310364, -0.3279739022254944, 0.4699665606021881, 0.36351561546325684, -0.35928529500961304, -0.09846198558807373, 0.784416913986206, 0.15755075216293335, 0.1603308767080307...
8958
the 1920s it was in common use as a photoresist in the production of printing plates for various photomechanical printing processes. Bitumen was the nemesis of many artists during the 19th century. Although widely used for a time, it ultimately proved unstable for use in oil painting, especially when mixed with the most common diluents, such as linseed oil, varnish and turpentine. Unless thoroughly diluted, bitumen never fully solidifies and will in time corrupt the other pigments with which it comes into contact. The use of bitumen as a glaze to set in shadow or mixed with other colors to
Asphalt
[ 0.3774036467075348, 0.2126234769821167, -0.3189558982849121, 0.35888561606407166, -0.1277090609073639, -0.2004050314426422, -0.15632760524749756, 0.5212234258651733, 0.4772600829601288, -0.46985065937042236, 0.19729089736938477, 0.7942173480987549, -0.007189037743955851, 0.4316769242286682...
8959
render a darker tone resulted in the eventual deterioration of many paintings, for instance those of Delacroix. Perhaps the most famous example of the destructiveness of bitumen is Théodore Géricault's Raft of the Medusa (1818–1819), where his use of bitumen caused the brilliant colors to degenerate into dark greens and blacks and the paint and canvas to buckle. The vast majority of refined asphalt is used in construction: primarily as a constituent of products used in paving and roofing applications. According to the requirements of the end use, asphalt is produced to specification. This is achieved either by refining or
Asphalt
[ 0.2971382439136505, 0.16202296316623688, -0.7542593479156494, 0.3575640320777893, 0.29089775681495667, 0.49277910590171814, -0.172343447804451, 0.38571077585220337, 0.0914965271949768, -0.6325682401657104, -0.2406974881887436, 0.7865390181541443, 0.039658207446336746, 0.3648328185081482, ...
8960
blending. It is estimated that the current world use of asphalt is approximately 102 million tonnes per year. Approximately 85% of all the asphalt produced is used as the 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 aggregates such as sand, gravel and crushed rock with asphalt, which acts as the binding agent. Other materials, such as recycled polymers (e.g., rubber tyres), may be added to the asphalt to modify its properties according to the
Asphalt
[ 0.6850546598434448, 0.5070187449455261, 0.1605563461780548, -0.10336308926343918, 0.10908746719360352, 0.19238807260990143, -0.011902578175067902, 0.35952436923980713, 0.1749664694070816, -0.8604292869567871, -0.27060404419898987, 0.9656028151512146, 0.06475187838077545, 0.1230981126427650...
8961
application for which the asphalt is ultimately intended. A further 10% of global asphalt production is used in roofing applications, where its waterproofing qualities are invaluable. The remaining 5% of asphalt is used mainly for sealing and insulating purposes in a variety of building materials, such as pipe coatings, carpet tile backing and paint. Asphalt is applied in the construction and maintenance of many structures, systems, and components, such as the following: The largest use of asphalt is for making asphalt concrete for road surfaces; this accounts for approximately 85% of the asphalt consumed in the United States. There are
Asphalt
[ 0.6423966288566589, 0.46551021933555603, 0.10086456686258316, -0.02687770314514637, 0.18684814870357513, 0.1222960352897644, 0.12306419759988785, 0.4901112914085388, 0.17594338953495026, -1.0145151615142822, -0.4801798462867737, 0.9851508736610413, 0.037715304642915726, 0.01657547242939472...
8962
about 4,000 asphalt concrete mixing plants in the US, and a similar number in Europe. Asphalt concrete pavement mixes are typically composed of 5% asphalt cement and 95% aggregates (stone, sand, and gravel). Due to its highly viscous nature, asphalt cement 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 asphalt and the aggregates, but warm-mix asphalt technologies allow producers to reduce the temperature required. The weight of an asphalt pavement depends upon the aggregate type, the asphalt, and the air void content. An
Asphalt
[ 0.36802181601524353, 0.6028072237968445, 0.08082465827465057, 0.03387193754315376, 0.2658824920654297, 0.3202744722366333, 0.07407354563474655, 0.18560051918029785, 0.3840154707431793, -0.8176210522651672, -0.20785529911518097, 0.6635665893554688, 0.06433898210525513, 0.16985464096069336, ...
8963
average example in the United States is about 112 pounds per square yard, per inch of pavement thickness. When maintenance is performed on asphalt pavements, such as milling to remove a worn or damaged surface, the removed material can be returned to a facility for processing into new pavement mixtures. The asphalt in the removed material can be reactivated and put back to use in new pavement mixes. With some 95% of paved roads being constructed of or surfaced with asphalt, a substantial amount of asphalt pavement material is reclaimed each year. According to industry surveys conducted annually by the
Asphalt
[ 0.3145042061805725, 0.24558210372924805, 0.15015524625778198, 0.1021437868475914, 0.1600227653980255, 0.31688329577445984, 0.24690936505794525, 0.481403648853302, -0.08242429792881012, -0.9707995057106018, -0.10267655551433563, 0.7125003337860107, 0.2778470516204834, 0.11598923802375793, ...
8964
Federal Highway Administration and the National Asphalt Pavement Association, more than 99% of the asphalt removed each year from road surfaces during widening and resurfacing projects is reused as part of new pavements, roadbeds, shoulders and embankments. 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 runways. Mastic asphalt is a type of asphalt that differs from dense graded asphalt (asphalt concrete) in that it has a higher asphalt (binder) content, usually around 7–10% of the whole aggregate mix, as opposed to rolled
Asphalt
[ 0.628614068031311, 0.3986835479736328, 0.4764764606952667, -0.000761674833483994, -0.04750904068350792, 0.0679776519536972, -0.08535106480121613, 0.5491246581077576, -0.03409430384635925, -1.0294166803359985, -0.25243210792541504, 0.5088635683059692, -0.0038473044987767935, -0.156292721629...
8965
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 and is spread in layers to form an impervious barrier about thick. A number of technologies allow asphalt to be mixed at much lower temperatures. These involve mixing with petroleum solvents to form "cutbacks" with reduced melting point or mixing with water to turn the asphalt into an emulsion. Asphalt emulsions contain up to 70% asphalt and typically less than 1.5% chemical additives. There are two main
Asphalt
[ 0.4120166301727295, 0.4145289659500122, 0.060094259679317474, 0.12388430535793304, 0.1341184377670288, -0.008442409336566925, 0.0758516862988472, 0.3371375799179077, 0.3005523681640625, -0.6569026708602905, -0.36544057726860046, 0.7703639268875122, 0.05065731704235077, 0.015084213577210903...
8966
types of emulsions with different affinity for aggregates, cationic and anionic. Asphalt emulsions are used in a wide variety of applications. Chipseal involves spraying the road surface with asphalt emulsion followed by a layer of crushed rock, gravel or crushed slag. Slurry seal involves the creation of a mixture of asphalt emulsion and fine crushed aggregate that is spread on the surface of a road. Cold-mixed asphalt can also be made from asphalt emulsion to create pavements similar to hot-mixed asphalt, several inches in depth, and asphalt emulsions are also blended into recycled hot-mix asphalt to create low-cost pavements. Synthetic
Asphalt
[ 0.6436487436294556, 0.19862481951713562, 0.01314406655728817, 0.2591451406478882, 0.05265263840556145, 0.0658077746629715, -0.2576521635055542, 0.424577921628952, 0.03683610260486603, -0.6797900795936584, -0.3228040039539337, 0.8659903407096863, 0.08047693222761154, 0.15097546577453613, ...
8967
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 shovels 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 Dr. Karl Clark of the University of Alberta during the 1920s. After extraction from the sand, the bitumen is fed into a bitumen upgrader which converts it into a light crude oil
Asphalt
[ 0.7099964022636414, 0.17452508211135864, -0.13046860694885254, 0.3087896406650543, 0.056740161031484604, 0.2822663486003876, -0.44273456931114197, 0.7108944058418274, 0.5403238534927368, -0.3045794665813446, -0.2708277404308319, 0.8923864960670471, 0.31978633999824524, 0.23028656840324402,...
8968
equivalent. This synthetic substance is fluid enough to be transferred through conventional oil pipelines and can be fed into conventional oil refineries without any further treatment. By 2015 Canadian bitumen upgraders were producing over per day of synthetic crude oil, of which 75% was exported to oil refineries in the United States. 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
Asphalt
[ 0.6444705724716187, 0.0760251060128212, -0.0905442163348198, 0.32612550258636475, -0.028612250462174416, 0.31437385082244873, -0.02015869878232479, 0.681294858455658, 0.32042571902275085, -0.568822979927063, -0.23554420471191406, 0.9065083861351013, 0.3891569972038269, 0.14269405603408813,...
8969
Shell Scotford Upgrader near Edmonton produces synthetic crude oil plus an intermediate feedstock for the nearby Shell Oil Refinery. 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. Canadian bitumen does not differ substantially from oils such as Venezuelan extra-heavy and Mexican heavy oil in chemical composition, and the real difficulty is moving the extremely viscous bitumen through oil pipelines to the refinery. Many modern oil refineries are extremely sophisticated and
Asphalt
[ 0.6114853620529175, 0.093570776283741, 0.18371081352233887, 0.4133935868740082, 0.11840895563364029, 0.2154504507780075, -0.3470268249511719, 0.6430195569992065, 0.3420299291610718, -0.6426577568054199, -0.16236069798469543, 0.9092656373977661, 0.4425729513168335, 0.06140958517789841, 0....
8970
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. By 2015
Asphalt
[ 0.4946524202823639, 0.04133540764451027, -0.11331017315387726, 0.2662155330181122, 0.17040739953517914, 0.04281941056251526, -0.15519507229328156, 0.6238763928413391, 0.22923138737678528, -0.6824774742126465, -0.17412860691547394, 0.7845534682273865, 0.2570188045501709, 0.18787942826747894...
8971
Canadian production and exports of non-upgraded bitumen exceeded that of synthetic crude oil at over per day, of which about 65% was exported to the United States. 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
Asphalt
[ 0.6289127469062805, 0.0457654669880867, -0.0803256630897522, 0.4899700880050659, -0.08575130254030228, 0.1229521632194519, -0.17351719737052917, 0.8336085081100464, 0.4846743047237396, -0.6538466811180115, -0.2778371572494507, 0.8331514000892639, 0.30837395787239075, -0.05767129361629486, ...
8972
is designed to have uniform refining characteristics to compete with internationally marketed heavy oils such as Mexican Mayan or Arabian Dubai Crude. Asphalt was used starting in the 1960s as an 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 fuels or radioactive sludges from sedimentation ponds. Bituminised radioactive waste containing highly radiotoxic alpha-emitting transuranic elements 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
Asphalt
[ 0.450591117143631, 0.05860292539000511, -0.1629430502653122, 0.19396620988845825, -0.04933948069810867, -0.20061829686164856, -0.25459733605384827, 0.7293463349342346, 0.638996422290802, -0.3780071437358856, -0.06614916026592255, 0.9132309556007385, 0.03339754417538643, 0.22965118288993835...
8973
(risks of fire, as occurred in a bituminisation plant at Tokai Works in Japan) and long-term stability problems related to their geological disposal in deep rock formations. One of the main problem is the swelling of asphalt exposed to radiation and to water. Asphalt swelling is first induced by radiation because of the presence of hydrogen gas bubbles generated by alpha and gamma radiolysis. 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
Asphalt
[ 0.2205677479505539, 0.45132267475128174, 0.08699368685483932, -0.0706602931022644, 0.2807520627975464, -0.3186689615249634, 0.22406749427318573, 0.2673090696334839, 0.18531377613544464, -0.8998145461082458, -0.2551705837249756, 0.7071505784988403, 0.03730088099837303, 0.36208105087280273, ...
8974
is then responsible for osmotic effects inside the bituminised matrix. The water moves in the direction of the concentrated salts, the asphalt acting as a 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
Asphalt
[ 0.13010281324386597, 0.36001086235046387, 0.14434103667736053, 0.050279006361961365, 0.281962513923645, -0.17903774976730347, 0.03557046502828598, 0.3191838264465332, 0.30888381600379944, -0.8535584211349487, -0.3502020537853241, 0.8982781767845154, 0.15110667049884796, 0.2097880244255066,...
8975
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 anions. This makes the disposal of medium-level bituminised waste very challenging. Different type of asphalt have been used: blown bitumen (partly oxidized with air oxygen at high temperature
Asphalt
[ 0.4011501669883728, 0.37689411640167236, -0.37840011715888977, 0.3479204773902893, -0.13217535614967346, -0.04166211187839508, 0.0774899423122406, 0.4473634660243988, 0.4939963221549988, -0.7040233612060547, -0.30211421847343445, 0.8904100060462952, 0.2015429586172104, 0.3663721978664398, ...
8976
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. Concrete encapsulation of radwaste is presently considered a safer alternative by the nuclear industry and the waste management organisations. Roofing shingles account for most of the remaining asphalt consumption. Other uses include cattle sprays, fence-post treatments, and waterproofing for fabrics. Asphalt is used to make Japan black, a lacquer known especially for its use on iron
Asphalt
[ 0.391486793756485, 0.16746945679187775, -0.26105040311813354, 0.15042681992053986, 0.09339090436697006, 0.04619140923023224, 0.03161695972084999, 0.40599483251571655, 0.42210647463798523, -0.5348390340805054, -0.474105566740036, 1.006467580795288, 0.1953219622373581, 0.18551771342754364, ...
8977
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. Asphalt is also used to seal some alkaline batteries during the manufacturing process. About 40,000,000 tons were produced in 1984. It is obtained as the "heavy" (i.e., difficult to distill) fraction. Material with a boiling point greater than around 500 °C is considered asphalt. Vacuum distillation separates it from the other components in crude oil (such as naphtha, gasoline and diesel). The resulting material
Asphalt
[ 0.43981754779815674, 0.3716551661491394, -0.12856172025203705, 0.02811790630221367, 0.2508904039859772, 0.05289249122142792, -0.15180353820323944, 0.4347628653049469, 0.4637216329574585, -0.23759932816028595, -0.2623997628688812, 1.060699701309204, 0.15919971466064453, 0.17297619581222534,...
8978
is typically further treated to extract small but valuable amounts of lubricants and to adjust the properties of the material to suit applications. In a de-asphalting unit, the crude asphalt is treated with either propane or butane in a supercritical phase to extract the lighter molecules, which are then separated. Further processing is possible by "blowing" the product: namely reacting it with oxygen. This step makes the product harder and more viscous. Asphalt is typically stored and transported at temperatures around . Sometimes diesel oil or kerosene are mixed in before shipping to retain liquidity; upon delivery, these lighter materials
Asphalt
[ 0.3738439679145813, 0.3315272927284241, 0.07118885219097137, 0.08367303758859634, 0.27423790097236633, -0.09576620906591415, -0.11003180593252182, 0.2892818748950958, 0.44946810603141785, -0.6698132753372192, -0.5058740377426147, 1.0344164371490479, 0.19407197833061218, 0.16634899377822876...
8979
are separated out of the mixture. This mixture is often called "bitumen feedstock", or BFS. Some dump trucks route the hot engine exhaust through pipes in the dump body to keep the material warm. The backs of tippers carrying asphalt, as well as some handling equipment, are also commonly sprayed with a releasing agent before filling to aid release. Diesel oil is no longer used as a release agent due to environmental concerns. Naturally occurring crude bitumen impregnated in sedimentary rock is the prime feed stock for petroleum production from "oil sands", currently under development in Alberta, Canada. Canada has
Asphalt
[ 0.6037483215332031, 0.21551114320755005, -0.11225614696741104, 0.1651088297367096, 0.1504060924053192, -0.13870641589164734, -0.3101743161678314, 0.6106868982315063, 0.5195900797843933, -0.4445541501045227, -0.3924279510974884, 0.8430880308151245, 0.12059717625379562, 0.20185042917728424, ...
8980
most of the world's supply of natural bitumen, covering 140,000 square kilometres (an area larger than England), giving it the second-largest proven oil reserves in the world. The Athabasca oil sands are the largest bitumen deposit in Canada and the only one accessible to surface mining, although recent technological breakthroughs have resulted in deeper deposits becoming producible by "in situ" methods. Because of oil price increases after 2003, producing bitumen became highly profitable, but as a result of the decline after 2014 it became uneconomic to build new plants again. By 2014, Canadian crude bitumen production averaged about per day
Asphalt
[ 0.582304060459137, 0.17058993875980377, 0.018830737099051476, 0.363411009311676, -0.09276769310235977, 0.350386381149292, -0.18824326992034912, 1.0525277853012085, 0.2918716371059418, -0.553908109664917, -0.18601569533348083, 0.7102605104446411, 0.5814349055290222, 0.12199024856090546, 0...
8981
and was projected to rise to per day by 2020. The total amount of crude bitumen in Alberta that could be extracted is estimated to be about , which at a rate of would last about 200 years. Although uncompetitive economically, asphalt can be made from nonpetroleum-based renewable resources such as sugar, molasses and rice, corn and potato starches. Asphalt can also be made from waste material by fractional distillation of used motor oil, which is sometimes otherwise disposed of by burning or dumping into landfills. Use of motor oil may cause premature cracking in colder climates, resulting in roads
Asphalt
[ 0.7322631478309631, 0.31415048241615295, 0.06153323873877525, 0.39323335886001587, 0.13467885553836823, 0.1504499614238739, 0.19613201916217804, 0.6439129114151001, 0.5763954520225525, -0.6743500828742981, -0.1410878747701645, 0.7906025052070618, 0.3103078603744507, -0.08533275127410889, ...
8982
that need to be repaved more frequently. Nonpetroleum-based asphalt binders can be made light-colored. Lighter-colored roads absorb less heat from solar radiation, reducing their contribution to the urban heat island effect. Parking lots that use asphalt alternatives are called green parking lots. Selenizza is a naturally occurring solid hydrocarbon bitumen found in native deposits in Selenice, in Albania, the only European asphalt mine still in use. The bitumen is found in the form of veins, filling cracks in a more or less horizontal direction. The bitumen content varies from 83% to 92% (soluble in carbon disulphide), with a penetration value
Asphalt
[ 0.44837066531181335, 0.0767228975892067, -0.2010044902563095, 0.11323612928390503, 0.2733449637889862, 0.17171457409858704, 0.11222125589847565, 0.6098911166191101, 0.1824275106191635, -0.676179051399231, -0.25410765409469604, 0.7236986756324768, 0.08432071655988693, 0.2608371078968048, ...
8983
near to zero and a softening point (ring and ball) around 120 °C. The insoluble matter, consisting mainly of silica ore, ranges from 8% to 17%. Albanian bitumen extraction has a long history and was practiced in an organized way by the Romans. After centuries of silence, the first mentions of Albanian bitumen appeared only in 1868, when the Frenchman Coquand published the first geological description of the deposits of Albanian bitumen. In 1875, the exploitation rights were granted to the Ottoman government and in 1912, they were transferred to the Italian company Simsa. Since 1945, the mine was exploited
Asphalt
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8984
by the Albanian government and from 2001 to date, the management passed to a French company, which organized the mining process for the manufacture of the natural bitumen on an industrial scale. Today the mine is predominantly exploited in an open pit quarry but several of the many underground mines (deep and extending over several km) still remain viable. Selenizza is produced primarily in granular form, after melting the bitumen pieces selected in the mine. Selenizza is mainly used as an additive in the road construction sector. It is mixed with traditional asphalt to improve both the viscoelastic properties and
Asphalt
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8985
the resistance to ageing. It may be blended with the hot asphalt in tanks, but its granular form allows it to be fed in the mixer or in the recycling ring of normal asphalt plants. Other typical applications include the production of mastic asphalts for sidewalks, bridges, car-parks and urban roads as well as drilling fluid additives for the oil and gas industry. Selenizza is available in powder or in granular material of various particle sizes and is packaged in sacks or in thermal fusible polyethylene bags. A life-cycle assessment study of the natural selenizza compared with petroleum asphalt has
Asphalt
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8986
shown that the environmental impact of the selenizza is about half the impact of the road asphalt produced in oil refineries in terms of carbon dioxide emission. Although asphalt typically makes up only 4 to 5 percent (by weight) of the pavement mixture, as the pavement's binder, it is also the most expensive part of the cost of the road-paving material. During asphalt's early use in modern paving, oil refiners gave it away. However, asphalt is, today, a highly traded commodity. Its prices increased substantially in the early 21st Century. A U.S. government report states: The report indicates that an
Asphalt
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8987
"average" 1-mile (1.6-kilometer)-long, four-lane highway would include "300 tons of asphalt," which, "in 2002 would have cost around $48,000. By 2006 this would have increased to $96,000 and by 2012 to $183,000... an increase of about $135,000 for every mile of highway in just 10 years." People can be exposed to asphalt in the workplace by breathing in fumes or skin absorption. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit of 5 mg/m over a 15-minute period. Asphalt is basically an inert material that must be heated or diluted to a point where
Asphalt
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8988
it becomes workable for the production of materials for paving, roofing, and other applications. In examining the potential health hazards associated with asphalt, the International Agency for Research on Cancer (IARC) determined that it is the application parameters, predominantly temperature, that affect occupational exposure and the potential bioavailable carcinogenic hazard/risk of the asphalt emissions. In particular, temperatures greater than 199 °C (390 °F), were shown to produce a greater exposure risk than when asphalt was heated to lower temperatures, such as those typically used in asphalt pavement mix production and placement. IARC has classified asphalt as a Class 2B possible
Asphalt
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8989
carcinogen. Asphalt Asphalt, also known as bitumen (, ), is a sticky, black, and highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term asphaltum was also used. The word is derived from the Ancient Greek ἄσφαλτος "ásphaltos". The primary use (70%) of asphalt is in road construction, where it is used as the glue or binder mixed with aggregate particles to create asphalt concrete. Its other main uses are for bituminous waterproofing products, including production of
Asphalt
[ 0.5805751085281372, 0.19374269247055054, -0.2686258554458618, 0.2443661093711853, 0.20627078413963318, 0.02629353478550911, -0.10672590881586075, 0.6724405884742737, 0.5119554996490479, -0.5905768871307373, -0.4622775912284851, 0.8988367319107056, -0.008053737692534924, 0.3483096659183502,...
8990
American National Standards Institute The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. ANSI accredits standards that are developed by representatives of other standards organizations, government agencies, consumer groups, companies, and others. These standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same way. ANSI
"American National Standards Institute"
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8991
also accredits organizations that carry out product or personnel certification in accordance with requirements defined in international standards. The organization's headquarters are in Washington, D.C. ANSI's operations office is located in New York City. The ANSI annual operating budget is funded by the sale of publications, membership dues and fees, accreditation services, fee-based programs, and international standards programs. ANSI was originally formed in 1918, when five engineering societies and three government agencies founded the American Engineering Standards Committee (AESC). In 1928, the AESC became the American Standards Association (ASA). In 1966, the ASA was reorganized and became United States of
"American National Standards Institute"
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8992
America Standards Institute (USASI). The present name was adopted in 1969. Prior to 1918, these five founding engineering societies: had been members of the United Engineering Society (UES). At the behest of the AIEE, they invited the U.S. government Departments of War, Navy (combined in 1947 to become the Department of Defense or DOD) and Commerce to join in founding a national standards organization. According to Adam Stanton, the first permanent secretary and head of staff in 1919, AESC started as an ambitious program and little else. Staff for the first year consisted of one executive, Clifford B. LePage, who
"American National Standards Institute"
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8993
was on loan from a founding member, ASME. An annual budget of $7,500 was provided by the founding bodies. In 1931, the organization (renamed ASA in 1928) became affiliated with the U.S. National Committee of the International Electrotechnical Commission (IEC), which had been formed in 1904 to develop electrical and electronics standards. ANSI's members are government agencies, organizations, academic and international bodies, and individuals. In total, the Institute represents the interests of more than 270,000 companies and organizations and 30 million professionals worldwide. Although ANSI itself does not develop standards, the Institute oversees the development and use of standards by
"American National Standards Institute"
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8994
accrediting the procedures of standards developing organizations. ANSI accreditation signifies that the procedures used by standards developing organizations meet the Institute's requirements for openness, balance, consensus, and due process. ANSI also designates specific standards as American National Standards, or ANS, when the Institute determines that the standards were developed in an environment that is equitable, accessible and responsive to the requirements of various stakeholders. Voluntary consensus standards quicken the market acceptance of products while making clear how to improve the safety of those products for the protection of consumers. There are approximately 9,500 American National Standards that carry the ANSI
"American National Standards Institute"
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8995
designation. The American National Standards process involves: In addition to facilitating the formation of standards in the United States, ANSI promotes the use of U.S. standards internationally, advocates U.S. policy and technical positions in international and regional standards organizations, and encourages the adoption of international standards as national standards where appropriate. The Institute is the official U.S. representative to the two major international standards organizations, the International Organization for Standardization (ISO), as a founding member, and the International Electrotechnical Commission (IEC), via the U.S. National Committee (USNC). ANSI participates in almost the entire technical program of both the ISO and
"American National Standards Institute"
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8996
the IEC, and administers many key committees and subgroups. In many instances, U.S. standards are taken forward to ISO and IEC, through ANSI or the USNC, where they are adopted in whole or in part as international standards. Adoption of ISO and IEC standards as American standards increased from 0.2% in 1986 to 15.5% in May 2012. The Institute administers nine standards panels: Each of the panels works to identify, coordinate, and harmonize voluntary standards relevant to these areas. In 2009, ANSI and the National Institute of Standards and Technology (NIST) formed the Nuclear Energy Standards Coordination Collaborative (NESCC). NESCC
"American National Standards Institute"
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8997
is a joint initiative to identify and respond to the current need for standards in the nuclear industry. American National Standards Institute The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. ANSI accredits standards that are developed by representatives of other standards organizations, government agencies, consumer groups, companies, and others. These standards ensure that the characteristics and performance of products are
"American National Standards Institute"
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8998
Apollo 11 Apollo 11 was the spaceflight that landed the first two people on the Moon. Commander Neil Armstrong and Lunar Module Pilot Buzz Aldrin, both American, landed the lunar module "Eagle" on July 20, 1969, at 20:17 UTC. Armstrong became the first person to step onto the lunar surface six hours after landing on July 21 at 02:56:15 UTC; Aldrin joined him about 20 minutes later. They spent about two and a quarter hours together outside the spacecraft, and collected of lunar material to bring back to Earth. Command Module Pilot Michael Collins piloted the command module "Columbia" alone
"Apollo 11"
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8999
in lunar orbit while they were on the Moon's surface. Armstrong and Aldrin spent 21.5 hours on the lunar surface before rejoining "Columbia" in lunar orbit. Apollo 11 was launched by a Saturn V rocket from Kennedy Space Center on Merritt Island, Florida, on July 16 at 13:32 UTC, and was the fifth crewed mission of NASA's Apollo program. The Apollo spacecraft had three parts: a command module (CM) with a cabin for the three astronauts, and the only part that returned to Earth; a service module (SM), which supported the command module with propulsion, electrical power, oxygen, and water;
"Apollo 11"
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9000
and a lunar module (LM) that had two stages – a descent stage for landing on the Moon, and an ascent stage to place the astronauts back into lunar orbit. After being sent to the Moon by the Saturn V's third stage, the astronauts separated the spacecraft from it and traveled for three days until they entered lunar orbit. Armstrong and Aldrin then moved into "Eagle" and landed in the Sea of Tranquillity. The astronauts used "Eagle"s ascent stage to lift off from the lunar surface and rejoin Collins in the command module. They jettisoned "Eagle" before they performed the
"Apollo 11"
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