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<?xml version="1.0" encoding="UTF-8"?><rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" > <channel> <title>Ishtarcompany</title> <atom:link href="https://ishtarcompany.com/feed/" rel="self" type="application/rss+xml" /> <link>https://ishtarcompany.com/</link> <description>supplying and distribution of Petroleum, Petrochemicals and Minerals</description> <lastBuildDate>Mon, 29 Apr 2024 05:15:10 +0000</lastBuildDate> <language>en-US</language> <sy:updatePeriod> hourly </sy:updatePeriod> <sy:updateFrequency> 1 </sy:updateFrequency> <generator>https://wordpress.org/?v=6.5.2</generator> <image> <url>https://ishtarcompany.com/wp-content/uploads/2023/07/ishtar-fav-icon.png</url> <title>Ishtarcompany</title> <link>https://ishtarcompany.com/</link> <width>32</width> <height>32</height></image> <item> <title>Caustic soda handeling and storage</title> <link>https://ishtarcompany.com/articles/caustic-soda-handeling-and-storage/?utm_source=rss&utm_medium=rss&utm_campaign=caustic-soda-handeling-and-storage</link> <dc:creator><![CDATA[Mohsen Helmi]]></dc:creator> <pubDate>Wed, 24 Feb 2021 11:30:32 +0000</pubDate> <category><![CDATA[articles]]></category> <guid isPermaLink="false">https://ishtarcompany.com/?p=3138</guid> <description><![CDATA[<p>Liquid caustic soda is available from many plants and terminals in tank truck, tank car, barge and ship quantities. Each form of transportation has its own advantages. The type of service selected will depend upon such factors as size and location of storage, rate of consumption, plant location, freight rates, etc. Caustic soda, liquid, is […]</p><p>The post <a href="https://ishtarcompany.com/articles/caustic-soda-handeling-and-storage/">Caustic soda handeling and storage</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></description> <content:encoded><![CDATA[<p><span class="fontstyle0"><a href="https://ishtarcompany.com/caustic-soda-production-process/"> Liquid caustic soda</a> is available from many plants and terminals in tank truck, tank car,<br />barge and ship quantities. Each form of transportation has its own advantages. The type of service selected will depend upon such factors as size and location of storage, rate of consumption, plant location, freight rates, etc.<br />Caustic soda, liquid, is regulated by the U.S. Department of Transportation (DOT) and is classified as a corrosive material.<br />The DOT identification number is UN I824 for liquid caustic soda. Caustic soda <span class="fontstyle2">in any concentration must be respected by everyone who handles and uses it. Before starting to work with it, the user should be aware of its properties, know what safety precautions to follow, and know how to react in case of contact.<br />Accidental exposure to caustic soda may occur under several conditions. Potentially hazardous situations include handling and packaging operations, equipment cleaning and repair, decontamination following spills and equipment failures.<br />Employees who may be subject to such exposure must be provided with proper personal protective equipment and trained in its use.</span><br />PROTECTIVE PRACTICES<br /><span class="fontstyle2">• Avoid breathing dust, mist or spray of caustic soda.<br />• Wear proper protective equipment. If warranted, wear approved respiratory protection.<br />• Keep equipment clean by washing off any accumulation of caustic soda.<br />• Weld pipelines where practical. Use flanged joints with gaskets made of caustic soda resistant material such as rubber, PTFE, or EPDM rubber. If a screwed fitting is used, apply Teflon</span><span class="fontstyle3">® </span><span class="fontstyle2">tape to the threads.<br />• When disconnecting equipment for repairs, first verify that there is no internal pressure on the<br />equipment and that the equipment has been drained and washed.<br />• Provide storage tanks with suitable overflow pipes. Overflow pipes should be directed near the bottom of the diked area.<br />• Shield the packing glands of pumps to prevent spraying of caustic solutions in the event of a leak.<br />• When releasing air pressure from a pressurized system, take every precaution to avoid spurts or sprays of caustic solution.</span><br />When making solutions, </span><span class="fontstyle2">always </span><span class="fontstyle0">add the caustic soda slowly to the surface of the water with constant agitation. </span><span class="fontstyle2">Never add the water to the caustic soda. </span><span class="fontstyle0">Always start with lukewarm water (80 -100°F). Never start with hot or cold water. Dangerous boiling or splattering can occur if caustic soda is added too rapidly, allowed to concentrate in one area or added to hot or cold liquids. Care must be taken to avoid these situations.<br />• In case of a spill or leak, stop the leak as soon as possible. After containment, collect the spilled material and transfer to a chemical waste area. Remove large liquid spills by vacuum truck. Neutralize residue with dilute acid. Flush spill area with water and follow with a liberal covering of sodium bicarbonate or other acceptable drying agent.</span></p><p>The post <a href="https://ishtarcompany.com/articles/caustic-soda-handeling-and-storage/">Caustic soda handeling and storage</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></content:encoded> </item> <item> <title>Caustic soda Production process</title> <link>https://ishtarcompany.com/articles/caustic-soda-production-process/?utm_source=rss&utm_medium=rss&utm_campaign=caustic-soda-production-process</link> <dc:creator><![CDATA[Mohsen Helmi]]></dc:creator> <pubDate>Wed, 24 Feb 2021 10:19:47 +0000</pubDate> <category><![CDATA[articles]]></category> <guid isPermaLink="false">https://ishtarcompany.com/?p=3135</guid> <description><![CDATA[<p>Caustic soda (sodium hydroxide or NaOH) is most commonly manufactured by the electrolysis of a sodium chloride (NaCl) solution. Ishtar manufactures caustic soda flakes using either membrane or diaphragm electrolytic cells. It is not used mercury based electrolytic cells to produce caustic soda. The co-products formed from the electrolytic production of caustic soda are chlorine […]</p><p>The post <a href="https://ishtarcompany.com/articles/caustic-soda-production-process/">Caustic soda Production process</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></description> <content:encoded><![CDATA[<p><span class="fontstyle0"><a href="https://ishtarcompany.com/caustic-soda-flakes/">Caustic soda</a> (<a href="https://ishtarcompany.com/caustic-soda-flakes/">sodium hydroxide</a> or NaOH) is most commonly manufactured by the electrolysis of a sodium chloride (NaCl) solution. Ishtar manufactures <a href="https://ishtarcompany.com/caustic-soda-flakes/">caustic soda flakes</a> using either membrane or diaphragm electrolytic cells. It is not used mercury based electrolytic cells to produce caustic soda. The co-products formed from the electrolytic production of caustic soda are chlorine and hydrogen.<br />The largest users of caustic soda are the pulp and paper, detergent and chemical industries. Caustic soda is also used in the alumina, oil and gas and textile industries, mostly for its alkalinity value. Ishtar has played a leading role in providing caustic soda to meet the increasing demands of industry.<br />Ishtar plants are strategically located to conveniently and economically serve industry. Terminals are used to maintain stocks of our caustic soda in many principal cities. Distributor stocks are also available in these and many other cities and form a network of supply for the end user’s convenience.</span></p><p><span class="fontstyle0"><a href="https://ishtarcompany.com/caustic-soda-flakes/">Liquid caustic soda</a> is available as a 50% solution in two main grades. The name of the grades corresponds to the equipment used to produced the caustic soda; membrane grade and diaphragm grade.</span></p><p>To be technically correct, only molten caustic soda should be called liquid, but since the term liquid caustic soda has historically been used to describe solutions of caustic soda, it is used in this document interchangeably with the term solution.</p><p><strong> <span class="fontstyle0">Principal <a href="https://ishtarcompany.com/caustic-soda-flakes/">Uses of Caustic Soda</a></span> </strong></p><p><span class="fontstyle0">Caustic soda is one of the very few chemicals utilized in a very broad range of applications. Some principal products or processes in which caustic soda is used are:<br />• Acid Neutralization<br />• Agricultural Chemicals<br />• Aluminum<br />• Battery Recycling<br />• Bleach<br />• Boiler Compounds<br />• Cellulose Film<br />• Chemicals:<br />Ammonia<br />Amyl Amines<br />Cresol<br />Ethylene Amines<br />Formic Acid<br />Glycerine</span></p><p><span class="fontstyle0">Maleic Anhydride<br />Pentaerythritol<br />Phenol<br />Propylene Oxide<br />Polycarbonates<br />Salicylic Acid<br />Sodium Aluminate<br />Sodium Hydrosulfide<br />Sodium Hypochlorite<br />Sodium Phosphates<br />Styrene<br />Vinyl Chloride Monomer<br />• Cleaning Formulations<br />• Corn Syrup<br />• Detergents<br />• Drain Cleaners<br />• Dyestuffs<br />• Ethanol Fermentation<br />• Food Processing<br />• Fruit & Vegetable Peeling</span></p><p><span class="fontstyle0">• Glass-Batch Wetting<br />• Ion-Exchange Resin<br />Regeneration<br />• Metal Production and Casting<br />• Ore Flotation and Processing<br />• Paint Removers<br />• Petroleum Refining<br />• pH Adjustment<br />• Pharmaceuticals<br />• Pigments<br />• Pool & Spa chemicals<br />• Pulp & Paper<br />• Rayon<br />• Silicates<br />• Soap<br />• Surfactants<br />• Textile Bleaching, Dyeing, and<br />Mercerizing<br />• Vegetable Oil Processing<br />• Water Treatment</span></p><p><span class="fontstyle0"><a href="https://ishtarcompany.com/caustic-soda-flakes/">Caustic soda manufacturers</a> is producing by an electrolyte process as shown below. Brine, prepared from sodium chloride (NaCl), is electrolyzed in either a membrane cell or a diaphragm cell.<br />The production of caustic soda (NaOH) also results in the co-products of chlorine and hydrogen. In the membrane process, a solution of approximately 30% in strength is formed. The solution is then sent to evaporators, which concentrate it to a strength of 50% by removing the appropriate amount of water. The diaphragm process is very<br />similar to the membrane process except that a solution of only 10-12% is formed in the cell.<br />Therefore, additional evaporation is required to reach the saleable concentration of 50%. The caustic soda solution is inventoried in storage tanks prior to shipment. The product is shipped in tank trucks, railcars, barges and ships. </span></p><p><span class="fontstyle0">The major difference in the two grades is the amount of starting material (sodium chloride) remaining in the final product. Membrane grade caustic soda will have less than 100ppm of the sodium chloride remaining in the product.<br />Diaphragm grade material will have less than 1.2% sodium chloride.<br />Several other differences can be seen in the products when the specification sheets are compared.</span></p><p>The post <a href="https://ishtarcompany.com/articles/caustic-soda-production-process/">Caustic soda Production process</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></content:encoded> </item> <item> <title>Bitumen Applications</title> <link>https://ishtarcompany.com/articles/uses-of-bitumen/?utm_source=rss&utm_medium=rss&utm_campaign=uses-of-bitumen</link> <dc:creator><![CDATA[Mohsen Helmi]]></dc:creator> <pubDate>Sun, 21 Feb 2021 07:55:14 +0000</pubDate> <category><![CDATA[articles]]></category> <guid isPermaLink="false">https://ishtarcompany.com/?p=3132</guid> <description><![CDATA[<p>The term “bitumen” refers to the tar-like petroleum deposits found in oil sands. Generally, this thick, black, viscous crude oil must be heated or diluted with hydrocarbons before it will flow. The terms “bitumen” and “bitumens, oxidized” may be used interchangeably with “asphalt” and “asphalt, oxidized”, respectively . Other synonyms for bitumen are “Asphaltic bitumen”, […]</p><p>The post <a href="https://ishtarcompany.com/articles/uses-of-bitumen/">Bitumen Applications</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></description> <content:encoded><![CDATA[<p>The term “<a href="https://ishtarcompany.com/iran-bitumen/">bitumen</a>” refers to the tar-like petroleum deposits found in oil sands. Generally, this thick, black, viscous crude oil must be heated or diluted with hydrocarbons before it will flow. The terms “bitumen” and “bitumens, oxidized” may be used<br />interchangeably with “asphalt” and “asphalt, oxidized”, respectively . Other synonyms for bitumen are “Asphaltic bitumen”,<br />“Asphaltum”, and “<a href="https://ishtarcompany.com/iran-bitumen/">Petroleum asphalt</a>”. When sold in its natural state, bitumen is used only for road paving; it must be processed rigorously for use in gasoline and diesel fuel production.<br />Bitumen is classified as follow:<br />1) <a href="https://ishtarcompany.com/iran-bitumen/">Bitumen 60/70</a> (CAS # 8052-42-4) has undergone a non-destructive distillation process during petroleum refining.<br />2) Extracts of steam-refined and air-refined bitumens (CAS # 64742- 93-4) have been oxidized by blowing air through at elevated temperatures, to produce desirable properties for industrial use in paving and roofing.<br />Bitumen is generally composed of aliphatic compounds, cyclic alkanes, aromatic hydrocarbons, and heterocyclic compounds. It is thought that fumes produced by heating asphalt at high temperatures are more likely to generate carcinogenic polycyclic aromatic compounds (such as benzo(a)pyrene) than fumes produced at lower temperatures. The chemical composition of asphalt depends on both the petroleum source and the manufacturing process (7), making it difficult to identify the specific component(s) responsible for adverse health effects in exposed workers (20). Extracts of steam-refined and air-refined bitumens (Bitumens, <a href="https://ishtarcompany.com/iran-bitumen/">oxidized bitumen</a>) have been classified by IARC as group 2B carcinogens, possibly carcinogenic to humans, with evidence from animal studies showing an increase in tumours at the site of injection in rats and mice, and tumours following skin application in mice (2). IARC has classified Bitumens as Group 3 – not classifiable as to their carcinogenicity to humans. Although there is some indication of increased cancer rates (including lung, oral & skin) in humans, epidemiological studies have been inconclusive due to concomitant exposure to coal tar pitches and other materials in roofing and paving asphalts (2,7). IARC has scheduled a review of asphalt and roofing activities.</p><p>Other adverse health effects following exposure to asphalt may include eye, respiratory system and skin irritation (7, 20). Dermal burns can occur when handling hot asphalt. Bitumens and extracts of steam refined and air-refined bitumens have been ranked by CAREX Canada as Group A (immediate high priority) for occupational settings and as Group B (possible high priority) for environmental settings. Prioritization was based on the carcinogenicity and other toxic properties of the substance, the prevalence of exposure in Canada, and the feasibility of assessing exposure.</p><p> </p><p>Main Uses</p><ul><li>The majority of asphalt produced in the US by <a href="https://ishtarcompany.com/iran-bitumen/">bitumen suppliers</a> is used in paving and roofing operations; only about 1% is used for waterproofing, damp-proofing, insulation, and paints.</li><li>Other uses for bitumen produced by <a href="https://ishtarcompany.com/iran-bitumen/">bitumen manufacturers</a> are in hydraulics, to protect metals against corrosion, and in electrical laminate adhesives, synthetic turf bases and sound insulation materials.</li><li>More than 80% of bitumen is used in various forms of road construction and maintenance.</li></ul><p> </p><p>Alberta’s oil sands are one of the world’s two largest sources of bitumen (14), amounting to an estimated 269 billion cubic metres. The oil sands underlie 140,200 square kilometres (23) and occur mainly in three regions: Athabasca (Fort McMurray), Peace River, and Cold Lake (North of Lloydminster).</p><p>The post <a href="https://ishtarcompany.com/articles/uses-of-bitumen/">Bitumen Applications</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></content:encoded> </item> <item> <title>What is Polymer modified bitumen</title> <link>https://ishtarcompany.com/articles/polymer-modified-bitumen1/?utm_source=rss&utm_medium=rss&utm_campaign=polymer-modified-bitumen1</link> <dc:creator><![CDATA[Mohsen Helmi]]></dc:creator> <pubDate>Sat, 20 Feb 2021 11:55:05 +0000</pubDate> <category><![CDATA[articles]]></category> <guid isPermaLink="false">https://ishtarcompany.com/?p=3129</guid> <description><![CDATA[<p>Bitumen Bitumen is a by-product of the fractional distillation of crude oil, but is also found in natural deposits. It has a unique combination of excellent water-proofing and adhesive properties which have been used effectively for more than 5000 years. Bitumen is a low-cost thermoplastic material which is widely used in roofing, road and pavement […]</p><p>The post <a href="https://ishtarcompany.com/articles/polymer-modified-bitumen1/">What is Polymer modified bitumen</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></description> <content:encoded><![CDATA[<p><strong>Bitumen</strong></p><p><a href="https://ishtarcompany.com/iran-bitumen/">Bitumen</a> is a by-product of the fractional distillation of crude oil, but is also found in natural deposits. It has a unique combination of excellent water-proofing and adhesive properties which have been used effectively for more than 5000 years. Bitumen is a low-cost thermoplastic material which is widely used in roofing, road and pavement applications. However, it is brittle in cold environments and softens readily in warm environments. One of the many methods employed to toughen bitumen is to blend it with polymers, either virgin or scrap, to produce polymer modified bitumen (PmB). In this chapter, an introduction to bitumen structure and properties, and a short review of the published literature on PmB is provided. Finally, an outline of the focus and content of each chapter in the book is described.</p><p>British Standard 3690, Part 1: 1989 defines bitumen as ‘A viscous liquid, or solid, consisting essentially of hydrocarbons and their derivatives, which is soluble in trichloroethylene and is substantially non-volatile and softens gradually when heated. It is black or brown in colour and possesses waterproofing and adhesive properties. It is obtained by refinery processes from petroleum, and is also found as a natural deposit or as a component of naturally occurring asphalt, in which it is associated with mineral matter’.</p><p>Man has made use of bitumen and bituminous binders for thousands of years. There are many references to bitumen in the Bible. In Genesis it refers to Noah’s waterproofing of the ark which was ‘pitched within and without with pitch’. Pitch is the Latin equivalent of ‘gwitu-men’ which was subsequently shortened to ‘bitumen’, then passing via French into English. Also, in the description of the building of the Tower of Babel, ‘they used bricks for stone and bitumen for mortar’ (Whiteoak, 1990). For over 5000 years <a href="https://ishtarcompany.com/iran-bitumen/">bitumen 60/70</a> has been used as a waterproofing and/or bonding agent (Abraham, 1945). The earliest recorded use was by the Sumerians around 3800 bc and the Egyptians used it in their mummification processes (Volke, 1993; Chirife et al., 1991).</p><p><strong><a href="https://ishtarcompany.com/iran-bitumen/">Polymer modified bitumen</a></strong></p><p>Bitumen occurs naturally, as mentioned above, and also remains after crude oil has been refined. Since the turn of the twentieth century demand for bitumen has far outweighed that available from naturally occurring sources. ‘Natural’ bitumen is found in the vicinity of subterranean crude oil deposits where surface seepages may occur at geological faults. The amount and nature of this naturally occurring material depend on a number of natural processes which modify the properties of this material. This product is often accompanied by mineral matter, the amount and nature of which depend on the circumstances which caused such an admixture to occur (Whiteoak,1990).<br />Crude oil originates from the remains of marine organisms and vegetable matter deposited with mud and fragments of rock on the ocean bed. Over millions of years organic matter and mud accumulate into layers hundreds of metres thick, the immense weight of the upper layers compressing the lower layers into sedimentary rock. Conversion of organisms and vegetable matter into hydrocarbons of crude oil is thought to be the result of the effect of heat from the earth’s crust and of pressure applied by the upper sedimentary layers, possibly aided by the effects of bacterial action and radioactive bombardment. as further layers of sediment were deposited on the sedimentary rock where the oil had formed, the additional pressure squeezed the oil sideways and upwards through porous rock. Porous rock extends to the earth’s surface, allowing oil to seep through, resulting in surface seepages (Whiteoak, 1990).<br />In general, there are four main oil producing regions in the world: the USA, Russia, the Middle East and the countries around the Caribbean. Bitumen is obtained by the fractional distillation of the crude oil at 300–350°C. Figure 1.1 shows a schematic diagram of the distillation process. The lighter fractions (e.g. propane and butane) come off first, followed by naphtha, kerosene and gas oil, distillates and short residue. It is this short residue which is the feedstock used in the manufacture of many different grades of bitumen. Oxygen is blown through the short residue and, depending on the temperatures and pressures used, and how much oxygen is added, different grades of bitumen are obtained. In the UK bitumen is generally classified into four grades:<br />1. <a href="https://ishtarcompany.com/iran-bitumen/">Penetration Grade Bitumen</a>: specified by penetration (British Standard 2000, Part 49: 1983) and softening point (British Standard 2000, Part 58: 1983), tests.<br />2. <a href="https://ishtarcompany.com/iran-bitumen/">Cutback grades</a> (to which kerosene has been added): specified by viscosity.<br />3. Hard grades: specified by penetration test and softening point range.<br />4. Oxidised grades: specified by penetration and softening point tests and also by solubility criteria.</p><p><img fetchpriority="high" decoding="async" class="aligncenter wp-image-3130 size-full" src="https://ishtarcompany.com/newen/wp-content/uploads/2021/02/bitumen-diagram.jpg" alt="bitumen diagram" width="779" height="654" srcset="https://ishtarcompany.com/wp-content/uploads/2021/02/bitumen-diagram.jpg 779w, https://ishtarcompany.com/wp-content/uploads/2021/02/bitumen-diagram-300x252.jpg 300w, https://ishtarcompany.com/wp-content/uploads/2021/02/bitumen-diagram-768x645.jpg 768w" sizes="(max-width: 779px) 100vw, 779px" /></p><p>The post <a href="https://ishtarcompany.com/articles/polymer-modified-bitumen1/">What is Polymer modified bitumen</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></content:encoded> </item> <item> <title>Sodium Bicarbonate—A Potent Ergogenic Aid?</title> <link>https://ishtarcompany.com/articles/sodium-bicarbonate-a-potent-ergogenic-aid/?utm_source=rss&utm_medium=rss&utm_campaign=sodium-bicarbonate-a-potent-ergogenic-aid</link> <dc:creator><![CDATA[Mohsen Helmi]]></dc:creator> <pubDate>Sat, 20 Feb 2021 11:50:27 +0000</pubDate> <category><![CDATA[articles]]></category> <guid isPermaLink="false">https://ishtarcompany.com/?p=3126</guid> <description><![CDATA[<p>Sodium Bicarbonate Sodium bicarbonate or sodium hydrogen carbonate is the chemical compound with the formula NaHCO3. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slight alkaline taste resembling that of washing soda (sodium carbonate). It is a component of the mineral natron and is […]</p><p>The post <a href="https://ishtarcompany.com/articles/sodium-bicarbonate-a-potent-ergogenic-aid/">Sodium Bicarbonate—A Potent Ergogenic Aid?</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></description> <content:encoded><![CDATA[<p><strong>Sodium Bicarbonate</strong></p><p><a href="https://barusgolden.com/sodium-bicarbonate/">Sodium bicarbonate</a> or <a href="https://ishtarcompany.com/sodium-bicarbonate/">sodium hydrogen carbonate</a> is the chemical compound with the formula <a href="https://ishtarcompany.com/sodium-bicarbonate/">NaHCO3</a>. Sodium bicarbonate is a white solid that is crystalline but often appears as a fine powder. It has a slight alkaline taste resembling that of washing soda (sodium carbonate). It is a component of the mineral natron and is found dissolved in many mineral springs. The natural mineral form is known as nahcolite. It is also produced artificially. Since it has long been known and is widely used, the salt has many related names such as baking soda, bread soda, cooking soda, bicarbonate of soda. Colloquially, its name is shortened to sodium bicarb.</p><p><strong>Role of Sodium Bicarbonate during High-Intensity Exercise</strong></p><p>During high-intensity exercise, muscles keep up with the demand for energy by converting some carbohydrate to lactic acid. A build-up of acid inside the muscle cells is one of the factors responsible for fatigue. This system’s total capacity is limited by the progressive increase in acidity within the muscles caused by the accumulation of lactate and H+ ions. Increased acidity ultimately inhibits energy transfer and the ability of the muscles to contract, leading to a decrease in exercise performance. Reducing the build-up of acid should reduce fatigue and allow the athlete to go faster or further. The body’s defences against an increase in acidity are the bicarbonate “buffers”, which help to neutralize the acid produced by intense exercise. The natural bicarbonate supply, part of the body’s buffering system, provides a rapid first line of defence against this increased acidity.</p><p><strong> Acting Mechanism</strong></p><p>Sodium bicarbonate is an alkalising agent and therefore reduces the acidity of the blood (known as a buffering action). By buffering acidity in the blood, bicarbonate may be able to draw more of the acid produced within the muscle cells out into the blood and thus reduce the level of acidity within the muscle cells themselves. This in turn could delay the onset of fatigue . Studies have confirmed that increased extracellular pH and higher bicarbonate raise the H+ and lactic acid efflux from active muscles. This is due to an increase in the activity of the Lactic acid/H+ co-transporter, which becomes more active as the intracellular/extracellular H+ gradient increases, during contraction as well as during recovery. It has been suggested that this mechanism causes a decrease in muscular fatigue, delaying the decrease in pH level and leading to a greater contractile capacity of the muscular tissue involved by means of enhanced muscle glycolytic ATP production. It has been proven that all of these metabolic perturbations imply a shift in muscle metabolism toward anaerobic energy production, which is especially advantageous during high-intensity exercise.</p><p>Taking a sufficient quantity of sodium bicarbonate (<a href="https://ishtarcompany.com/sodium-bicarbonate/">baking soda</a>) before high-intensity event makes the muscles and blood less acidic during the event and can enhance physical performance.</p><p><strong>Athletes Benefiting from Sodium Bicarbonate Loading</strong></p><p>Athletes have been practicing “soda loading” or “bicarbonate loading” for over 70 years in an attempt to delay the onset of muscular fatigue during prolonged anaerobic exercise. The specific athletes who might stand to benefit from bicarb supplementation are those who typically compete in events that last between 1 and 7 minutes, i.e.</p><p>400 m – 1500 m running, 100 m – 400 m swimming, sprint cycling, kayaking, rowing and canoeing events at intensities that fall between 80 and 125% of peak maximal oxygen uptake, and many team sports with their repeated nature of high intensity exercise. All these events stress the anaerobic glycolysis system significantly and produce a lot of acidity. Sports that are dependent on repeated anaerobic bursts may also benefit from bicarbonate loading.</p><p><strong>Conclusions</strong></p><p>In conclusion, there are sufficient data to suggest that <a href="https://ishtarcompany.com/sodium-bicarbonate/">sodium bicarbonate grades</a> can be used as a nutritional ergogenic aid or dietary supplement for improving performance in short term, high intensity exercise, provided it is taken in the recommended dosage of 300 mg (0.3g)/kilogram body weight. Continued use of bicarbonate may help athletes become less susceptible to the side effects and may give even larger improvements in performance</p><p>The post <a href="https://ishtarcompany.com/articles/sodium-bicarbonate-a-potent-ergogenic-aid/">Sodium Bicarbonate—A Potent Ergogenic Aid?</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></content:encoded> </item> <item> <title>Bitumen and Tar</title> <link>https://ishtarcompany.com/articles/bitumen-and-tar/?utm_source=rss&utm_medium=rss&utm_campaign=bitumen-and-tar</link> <dc:creator><![CDATA[Mohsen Helmi]]></dc:creator> <pubDate>Sun, 24 Feb 2019 08:43:57 +0000</pubDate> <category><![CDATA[articles]]></category> <guid isPermaLink="false">https://ishtarcompany.com/?p=2672</guid> <description><![CDATA[<p>Bitumen & Tar   Introduction Bituminous binders used in pavement construction works include both bitumen and tar. Both bitumen and tar have similar appearance, black in colour though they have different characteristics.   Origin Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae and other once-living things. When these organisms […]</p><p>The post <a href="https://ishtarcompany.com/articles/bitumen-and-tar/">Bitumen and Tar</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></description> <content:encoded><![CDATA[<h1>Bitumen & Tar</h1><p> </p><h1><span style="font-size: 14pt;">Introduction</span></h1><p>Bituminous binders used in pavement construction works include both <a href="https://ishtarcompany.com/iran-bitumen/">bitumen</a> and tar. Both bitumen and tar have similar appearance, black in colour though they have different characteristics.</p><p> </p><h1><span style="font-size: 14pt;">Origin</span></h1><p><strong> </strong>Naturally occurring deposits of bitumen are formed from the remains of ancient, microscopic algae and other once-living things. When these organisms died, their remains were deposited in the mud on the bottom of the ocean or lake where they lived. Under the heat and pressure of burial deep in the earth, the remains were transformed into materials such as bitumen, kerogen, or petroleum. Deposits at the La Brea Tar Pitsare an example. There are structural similarities between bitumens and the organic matter in carbonaceous meteorites. However, detailed studies have shown these materials to be distinct. <a href="https://ishtarcompany.com/iran-bitumen/">Asphalt </a>or bitumen can sometimes be confused with “tar”, which is a similar black, thermoplastic material produced by the destructive distillation of coal. During the early and mid20th century when town gas was produced, tar was a readily available product and extensively used as the binder for road aggregates. The addition of 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 (bitumen) has completely overtaken the use of tar in these applications.</p><p>BITUMEN is a petroleum product obtained by the distillation of petroleum crude.</p><p>TAR is a thermoplastic material obtained from the destructive distillation.</p><p>The <a href="https://ishtarcompany.com/iran-bitumen/">grade of bitumen</a> used for pavement construction work of roads and airfields are called paving grades and used for water proofing of structures and industrial floors etc. are called industrial grades.</p><p>The paving bitumen available in India is classified into two categories</p><ul><li>Paving bitumen from Assam petroleum denoted as A-type and designated as grades A35, A90.etc.</li></ul><ul><li>Paving bitumen from other sources denoted as S-type and designated as grades S35, S90 etc.</li></ul><p>The viscosity of bitumen is reduced some times by a volatile diluents this material is called <strong><a href="https://ishtarcompany.com/iran-bitumen/">Cutback bitumen</a>. </strong>The bitumen is suspended in a finely divided condition in an aqueous medium and stabilized with an emulsifier; the material is known as <strong>Emulsion</strong>.</p><p> </p><h1><span style="font-size: 14pt;">Difference between Bitumen and Tar</span></h1><table width="0"><tbody><tr><td style="text-align: center;" width="64"><strong>Sl. No. </strong></td><td style="text-align: center;" width="265"><strong>Bitumen </strong></td><td style="text-align: center;" width="288"><strong>Tar </strong></td></tr><tr><td style="text-align: center;" width="64">1</td><td style="text-align: center;" width="265">Bitumen is found in black to brown in colour</td><td style="text-align: center;" width="288">Tar is usually found in brown colour</td></tr><tr><td style="text-align: center;" width="64">2</td><td style="text-align: center;" width="265">Bitumen is obtained from fractional distillation of crude oil</td><td style="text-align: center;" width="288">Tar is obtained by destructive distillation of coal or wood</td></tr><tr><td style="text-align: center;" width="64">3</td><td style="text-align: center;" width="265">Bitumen is soluble in carbon disulphide and carbon tetra chloride</td><td style="text-align: center;" width="288">Tar is soluble in toluene</td></tr><tr><td style="text-align: center;" width="64">4</td><td style="text-align: center;" width="265">Molecular weight range for road bitumen is 400 to 5000</td><td style="text-align: center;" width="288">Molecular weight range for road tar is 150 to 3000</td></tr><tr><td style="text-align: center;" width="64">5</td><td style="text-align: center;" width="265">Bitumen consists of large amount of aromatic hydrocarbon</td><td style="text-align: center;" width="288">Tar consist of large amount of oily matter with lower molecular weight</td></tr><tr><td style="text-align: center;" width="64">6</td><td style="text-align: center;" width="265">Bitumen show resistance to coating road aggregate and also does not retain in presence of water</td><td style="text-align: center;" width="288">Tar coats more easily and retain it better in presence of water</td></tr><tr><td style="text-align: center;" width="64">7</td><td style="text-align: center;" width="265">Free carbon content is less</td><td style="text-align: center;" width="288">Free carbon content is more</td></tr><tr><td style="text-align: center;" width="64">8</td><td style="text-align: center;" width="265">It shows more resistance to weathering action</td><td style="text-align: center;" width="288">It shows less resistance to weathering action</td></tr><tr><td style="text-align: center;" width="64">9</td><td style="text-align: center;" width="265">Less temperature susceptibility</td><td style="text-align: center;" width="288">More temperature susceptibility</td></tr></tbody></table><h1></h1><h1><span style="font-size: 14pt;">Bitumen</span></h1><p>The source of road bitumen is either formed from petroleum or by natural processes as a result of geological forces.</p><p> </p><h1><span style="font-size: 14pt;">Different forms of bitumen <a href="https://ishtarcompany.com/iran-bitumen/">Cutback bitumen</a></span></h1><p>Normal practice is to heat Bitumen to reduce its viscosity. In some situations preference is given to use liquid binders such as cutback bitumen. In cutback bitumen Suitable solvent is used to lower the viscosity of the bitumen. From the environmental point of view also cutback bitumen is preferred. The solvent from the bituminous material will evaporate and the bitumen will bind the aggregate. Cutback bitumen is used for cold weather Bituminous road construction and Maintenance. The distillates used For preparation of cutback bitumen are naphtha, kerosene, diesel, oil and furnace oil. There are different types of cutback bitumen Like rapid curing(RC),medium curing(MC), And slow curing(SC).RC is recommended for Surface dressing and patchwork. MC is recommended For premix With less quantity of fine aggregates.SC is used For premix with appreciable quantity of fine aggregates.</p><p> </p><h1><span style="font-size: 14pt;"><a href="https://ishtarcompany.com/iran-bitumen/">Bitumen Emulsion</a></span></h1><p>Bitumen emulsion is a liquid product in which bitumen is suspended in a finely divided condition in an aqueous medium and stabilized by suitable material. Normally cationic type emulsions are used in India. The bitumen content in the emulsion is around 60% and the remaining is water. When the emulsion is applied on the road it breaks down resulting in release of water and the mix starts to set. The time of setting depends upon the grade of bitumen. The viscosity of bituminous emulsions can be measured as per IS:8887-1995.Threetypes of bituminous emulsions are available, which are Rapid setting(RS),Medium setting (MS),And Slow setting (SC).Bitumen Emulsions are ideal binders for hill road construction. Where Heating of bitumen or aggregates are difficult. Rapid Setting emulsions are used for surface dressing work. Medium Setting emulsions are preferred for premix jobs and patch repairs work. Slow setting Emulsions are preferred in rainy season.</p><p> </p><h1><span style="font-size: 14pt;">Bituminous primers</span></h1><p>In bituminous primer the distillate is absorbed by the road surface on which it is spread. The absorption there for depends on the porosity of the surface. Bitumen primers are use full on the stabilized surfaces and water bound macadam base courses. Bituminous primers are generally prepared on road sites by mixing <a href="https://ishtarcompany.com/iran-bitumen/">penetration bitumen</a> with petroleum distillate.</p><p><strong> </strong><strong> </strong></p><h1><span style="font-size: 14pt;"><a href="https://ishtarcompany.com/iran-bitumen/">Modified Bitumen</a></span></h1><p>Certain additives or blend of additives called as bitumen modifiers can improve properties of Bitumen and bituminous mixes. Bitumen treated with these modifiers is known as modified bitumen. Polymer modified bitumen(PMB)/crumb rubber modified Bitumen (CRMB) should be used only in wearing course depending upon the requirements of extreme climatic variations. The detailed specifications for modified bitumen have been issued by IRC: SP: 53-1999. It must be noted that the performance of PMB and CRMB is dependent on strict Control on Temperature during construction.</p><p><strong>The advantages of using <a href="https://ishtarcompany.com/iran-bitumen/">modified bitumen</a> are as follows: </strong></p><ol><li>Lower susceptibility to daily and seasonal temperature variations</li><li>Higher resistance to deformation at high pavement temperature</li><li>Better age resistance properties</li><li>Higher fatigue life for mixes</li><li>Better adhesion between aggregates and binder</li><li>Prevention of cracking and reflective cracking.</li></ol><p> </p><h1><span style="font-size: 14pt;">Types 1) Rock Asphalt </span></h1><ol><li>It consists of limestone, sand stone naturally impregnated with bitumen.</li><li>The mineral matter will be about 90% and bitumen content of 10%.</li></ol><p> </p><h1><span style="font-size: 14pt;">Types 2) Lake Asphalt</span></h1><ol><li>Mineral matter will be finely divided and dispersed through the bitumen</li><li>The whole mass is capable of flow</li><li>Type of lake asphalt used in road making in United Kingdom is Trinidad lake asphalt.</li><li>It is used in flexible road construction and also in rolled asphalt wearing courses.</li></ol><p> </p><h1><span style="font-size: 14pt;">Preparation of <a href="https://ishtarcompany.com/iran-bitumen/">Road Bitumen</a> from Petroleum </span></h1><p>The refining of petroleum is most complex procedure producing a tremendous range of products from the simplest hydrocarbon gas methane to the hardest bitumen with constituents of molecular weight of the order of several thousands.</p><p>The preparation of different forms of bitumen for road purposes from petroleum is illustrated in the above figure.</p><p> </p><p><strong><span style="font-size: 14pt;">PREPARATION OF ROAD BITUMEN</span><br /></strong></p><h1><span style="font-size: 14pt;">a) Distillation of Petroleum</span></h1><p>Bitumen is produced from selected crude oils by a process of concentration by distillation.</p><p>The distillate is obtained in the desired boiling point ranges by condensation in a fractionating column.</p><p>It is first to heat the crude oil to a temperature lower than 350°C under atmospheric pressure to drive off light fractions such as gasoline, kerosene and gas oil.</p><p>Further heating above 400°C is necessary to drive off heavier oils.</p><p>Refining of the topped crude is carried out by use of reduced pressures and steam injection in the fractionating column.</p><p>The incoming crude is pumped through a continuous pipe-still similar to that used in tardistillation plants, where it is raised to desired temperature (between 200 and 400° C)</p><p>It is then injected into a fractionating column where at the reduced pressure volatile components flash into vapours.</p><p>The vapours are condensed into fractions of decreasing boiling point by condensation at points at higher levels in the fractionating column.</p><p>A flow diagram representing the distillation of topped oil in a modern refinery is given in figure below:</p><p> </p><p><span style="font-size: 14pt;"><a href="https://ishtarcompany.com/iran-bitumen/"><strong>BITUMEN PRODUCTION </strong></a></span></p><h1><span style="font-size: 14pt;"><em>b</em>) Air-Rectification of Refinery Bitumen</span></h1><p>Bitumen produced by straight steam-refining from crude oils may be deficient in the components of high molecular weight which are insoluble in heptanes, asphaltenes fractions.</p><p>It is common practice to increase the asphaltene content by oxidation of the hot straight-run bitumen by a current of air blown through it.</p><p>These are bitumen of high softening point produced by an oxidation by air-blowing at high temperatures.</p><p>The oxidation is more extensive and the blown bitumens have rubbery qualities required for certain industrial purposes and not used as binders for road aggregates.</p><p> </p><h1><span style="font-size: 14pt;">Chemical Constitution of Bitumen</span></h1><p>Bitumen although formed from distillation process causes some changes which is closely related in chemical nature to its primary source i.e., the crude petroleum oil.</p><p>Bitumen is completely soluble in carbon-di-sulphide but most of them divide the bitumen soluble in carbon-di-sulphide into 3 fractions:</p><ol><li><strong>Carbenes:</strong> fraction insoluble in carbon tetrachloride.</li><li><strong>Asphaltenes</strong>: fraction insoluble in light aliphatic hydrocarbon solvent such as petroleum ether.</li><li><strong>Maltenes:</strong> fraction soluble in light aliphatic hydrocarbon solvent</li></ol><p> </p><p>The molecular weight of asphaltene fraction is estimated between 1800 and 1,40,000 and maltenes have molecular weight between 370 and 710. The hydrocarbons in petroleum are of four basic forms:</p><ol><li>Saturated aliphatic groups or paraffins</li><li>Naphthenic groups or cycloparaffins</li><li>Aromatic ring compounds</li><li>Aliphatic groups with olefin double bonds</li></ol><p> </p><p>Aliphatic group normally does not present in road bitumen. The approximate proportions of the other three groups in the molten groups can be obtained from modified Waterman analysis.</p><p>Many properties of bitumen, particularly the non-Newtonian flow properties suggest that bitumen is a colloidal system. The colloidal nature of bitumen is due to the presence of asphaltenes in association with high molecular weight material from the maltenes fraction, form a disperse phase. This complex is normally referred as ‘micellar phase’.</p><p>On the basis of flow properties, bitumen can be divided into two types, ‘sol’ type, in which there is little interaction between micelles or a ‘gel’ type in which interaction of micelles are great enough to cause a loose structure formation. Most of the distilled road bitumens are sol type, blowing leads to gel type structures.</p><p> </p><h1><span style="font-size: 14pt;">Requirements of Bitumen</span></h1><p>The desirable properties of bitumen depend on the mix type and construction.</p><ol><li>Mixing: type of materials used, construction method, temperature during mixing, etc.</li><li>Attainment of desired stability of the mix</li><li>To maintain the stability under adverse weather conditions</li><li>To maintain sufficient flexibility and thus avoid cracking of bituminous surface and</li><li>To have sufficient adhesion with the aggregates in the mix in presence of water</li></ol><p><strong> </strong></p><p><span style="font-size: 14pt;"><strong>Desirable Properties of Bitumen </strong></span></p><h1><span style="font-size: 14pt;">1) Viscosity</span></h1><p>The <a href="https://ishtarcompany.com/iran-bitumen/">viscosity of the bitumen</a> at the time of mixing and compaction should be adequate. This is achieved by heating the bitumen and aggregate prior to mixing or by use of cutbacks or emulsions of suitable grade.</p><p> </p><h1><span style="font-size: 14pt;">2) Temperature Susceptibility</span></h1><p>The bituminous material should not be highly temperature susceptible. During the hottest weather of the region the bituminous mix should not become too soft or unstable. During cold weather the mix should not become too hard and brittle, causing cracking. The material should be durable.</p><p> </p><h1><span style="font-size: 14pt;">3) Adhesion Property</span></h1><p>In presence of water the bitumen should not strip off from the aggregate. There has to be adequate affinity and adhesion between the bitumen and aggregate used in the mix.</p><p><strong> </strong></p><h1><span style="font-size: 14pt;">Tests on bitumen</span></h1><p>There are a number of tests to assess the properties of bituminous materials. The following tests are usually conducted to evaluate different properties of bituminous materials.</p><ol><li>Penetration test</li><li>Softening point test</li><li>Ductility test</li><li>Viscosity test</li><li>Specific gravity test 6. Heat stability test</li><li>Flash point test</li><li>Fire point test</li><li>Loss on heating test 7. Solubility test</li><li>Thin film oven test</li><li>Float test</li><li>Water content test</li></ol><p> </p><p><strong>1.Penetration test: </strong></p><p>An indirect method of measuring viscosity is the measure of penetration of a standard needle under standard conditions of load, time & temperature. The test measures the hardness or softness of bitumen in terms of penetration expressed in mm/10<sup>th</sup> of std needle.</p><p>Temperature= 25<sup>0</sup>C [test to be performed after sample is kept for 1hr in H<sub>2</sub>O bath at this temperature]</p><p>Load on needle = 100 g</p><p>Time in which penetration is recorded = 5 s</p><p>The penetration is measured by a graduated dial.</p><p>Bitumen is softens to a poring consistency a depth more than 15mm in the container is poured. The expected penetration sample is cooled in 60 min in air and 60 min in water before testing. The standard needle is positioned to get a penetration value for 5sec and is noted.</p><p>The penetration value obtained is represented in 80-100 or 80/100 grade bitumen at standard consistence and it range from 20-225mm.</p><p>In cold region bitumen with High penetration value is used.</p><p>In warm region low penetration value is used ex. 30/40 grade.</p><p>The factors which affect the Penetration test is test temperature, needle size and weight and period of cooling.</p><p> </p><p><strong>2.Softening point: </strong></p><p>The softening point is the temperature at which the substance attains a particular degree of softening under specified condition of test. A viscosity material like bitumen or tar doesn’t have a well defined softening point. However a std test determines the temperature at which a std ball will pass through a disc of bitumen contained in ring. The test is known as ring & ball test.</p><p>A brass ring of internal dia 17.5 mm at top and 15.9 mm at bottom and of depth 6.4mm.The steel ball of 9.5mm dia and 2.5g. Support distance is 25mm between the bottom of the ring and top surface of the bottom plate of support is provided. Glass container of 85mm dia and 120mm depth is used. The bitumen is heated to poring consistency and poured into ring and cooled for half an hour before testing. A brass ring containing the bitumen sample is suspended in H<sub>2</sub>O or glycerin at given temperature a steel ball is placed on the disc of bitumen. The liquid medium is then heated at a rate of 5<sup>0</sup>C increase per minute. Metal plate placed at a specified bituminous material touches the bottom at the softening point. With increase in temperature bitumen melts and come down with the weight of ball at particular temperature it touches the bottom plate that point temperature is noted.</p><p>The softening point is range between 35 to 75<sup>0</sup>C.</p><p>The liquid water is used for bitumen having softening point less than 80<sup>0</sup>C and Glycerine is for softening point more than 80<sup>0</sup>C.</p><p>Higher softening point indicates lower temp. susceptibility and in warm climet.</p><p>The factors which affect the softening points are quality and type of liquid used, weight of ball, distance between bottom of the ring and bottom base plate and rate of temperature.</p><p> </p><p><strong>3.Ductility test: </strong></p><p>In flexible pavement construction it is important that the binders form ductile thin film around the aggregate. This serves as a satisfactory binder in improving the physical interlocking of the aggregate bitumen mixes. Under traffic loads the bitumen layer is subjected to repeated deformation and recoveries. The binder material which does not possess sufficient ductility would crack and thus provide pervious pavement surface. The test is believed to measure the adhesive property of bitumen and its ability to stretch. The ductility of a binder is an indication of its elasticity & ability to deform under load & return to original condition upon removal of the load. A material which doesn’t possess adequate ductility would crack under a load.</p><p>This is unsatisfactory since water can penetrate into the surfacing through there cracks. The property is determined by measuring the distance that a std briquette of bitumen, necked to a cross section of 1 sq-cm will stretch without breaking when elongated at a rate of 5 cm/min at 27<sup>0</sup>C. The ductility values should be a minimum of 50 as per IS.</p><p>The briquette mould is filled with bitumen and cool for 30 min in air and 30 min in water before testing. Then it is fixed to expanding machine assembly which stretches the bitumen at a rate of 5cm/min and expands till to break and the point is noted by scale.</p><p>The factors which affect the ductility is pouring and test temperature, dimension of briquette mould, rate of pulling and period of cooling.</p><p> </p><p><strong>4.Viscosity Test: </strong></p><p>Viscosity is the property of a fluid that determines the resistance offered by the fluid to a shearing force under laminar flow conditions, it is thus the opposite of fluidity.</p><p>The determination of viscosity is generally done by efflux viscometers. They work on common principles, though they differ in detail. The liquid under test is poured to a specified level into a container surround by water or oil bath providing temperature control at the base of the container is a small orifice with a simple valve control on opening valve, the time in seconds is recorded for a stated quantity of liquid to discharge into a measuring liquid below. The different type of viscosity testing operator is there they are Efflux viscometer, Standard tar viscometer (10mm dia orifice and 50ml fluid to discharge), Saybolt furol viscometer (3mm dia orifice and 60ml fluid to discharge).</p><p>The bitumen is placed in to a standard tar viscometer or efflux viscometer and its temperature is raised to test temperature specified (35, 40, 45, 55& 60<sup>0</sup>C). When the temperature reaches respective test temperature orifice valve is open time elapse is noted to collect the bitumen of 50ml. The time required to collect a bottom container of 50ml is five indirectly the viscosity of bitumen. Then is specified in VG 10, VG20, VG 30 and VG 40.</p><p> </p><p><strong>5.Specific gravity test: </strong></p><p>In most applications bitumen is weighed, but finally in use with aggregate the bitumen content is converted on volume basis. Hence determine of specific gravity value is required for conversion of weight to volume. Specific gravity of a binder doesn’t influence its behavior but all the same, its value is needed for mix design.</p><p>Specific gravity of bitumen varies from 0.97 to 1.02.</p><p>Specific gravity of tar varies from 1.16 to 1.28.</p><p>There are two methods to test the specific gravity of bitumen</p><ol><li>Pycnometer method</li><li>Balance method</li></ol><p>Generally balance method is used in that a cup of 50ml capacity is used and it is oiled before using. The bitumen is poured in to cup and cooled and its weight <strong>e</strong> is noted and weight of cup with bitumen when immersed in distilled water is weighed <strong>f. </strong>Specific gravity of bitumen is the ratio of <strong>e</strong> to the difference between (<strong>e</strong> and <strong>f</strong>).</p><p>It is used to convert the weight in to volume. Determines Purity of bitumen if the impurity present in the bitumen by showing high value of specific gravity.</p><p> </p><p><strong>6.Heat stability test: </strong></p><p>When a bituminous binder is heated continuously it starts emitting volatile vapors above a certain temperature and these volatile vapors can momentarily catch fire in form of flash and continued heating get fired.</p><p> </p><p><strong>7.Flash point: </strong></p><p>The flash point of bitumen is that temperature at which it gives off vapors, which ignites in the pressure of a flame, but don’t continue to burn. The flame point is an induction of critical temperature at & above which suitable precautions should be taken to eliminate fire hazards. The ISI test describes the Penske-Martin method. The method involves a cup into which the bitumen is filled. The bitumen sample is then heated at a rate of 5-6<sup>0</sup>C/min stirring the material continuously.</p><p>The test flame is applied at intervals. The flash point is taken at the temperature read on the thermometer when flame causes a bright flash in the interior of cup in a closed system & at the surface of material in open system. It is 220<sup>0</sup>c.</p><p> </p><p><strong>8.</strong><strong> Fire point test: </strong></p><p>If heating is continued beyond the flash point, the vapors ignite in the pressure of a flame & continue to burn indicating the fire point temperature. There is no standard method to determine the spontaneous ignition temperature, which can only broadly indicate.</p><p> </p><p><strong>9.</strong><strong> Loss on heating test: </strong></p><p>The effect of heat on a bituminous binder is the loss of volatile constituents. This loss causes the binder to harden. Thus one method of testing the desirable property of a binder is to find out the loss on heating. This is achieved by an accelerated heating test a 50gm sample is weight is taken and maintained at a temperature of 160<sup>0</sup>c<sup> </sup> for 5hours. Then it expressed as a percentage of loss in original weight is determined.</p><p> </p><p><strong>10.Solubility test: </strong></p><p>It has already been indicated that all bitumen are substantially soluble in CS<sub>2</sub>. This is one of the points that define bitumen. Hence any impurity in bitumen in the form of inert minerals, carbon, salts etc. could be quantitatively analyzed by dissolving the samples of bitumen in any of the two solvents.</p><p>A sample of 2g of bitumen is dissolved in 100ml of solvent and filtered in soluble material is washed, dried and weighed then it is expressed in percent of original sample. The Indian specifications require 99% solubility.</p><p><strong> </strong></p><p><strong>11.Thin film oven test: </strong></p><p>In this test, a sample of bitumen is subjected to hardening conditions as would be expected during hot mixing operations. A 50ml sample of bitumen is placed in a flat bottomed sample pan 140mm inside diameter & 10mm deep, the weighed sample & container are placed in a shelf which rotates at 5 to 6 rpm for 5 hrs in a ventilated oven maintained at 163<sup>0</sup>C. The loss in weight of the sample is expressed as % of the original weight. This method is then used for identify short term aging or hardening of bitumen.</p><p> </p><p><span style="font-size: 14pt;"><strong>Tar </strong></span></p><p>Tar is the viscous liquid obtained when natural organic materials such as wood and coal carbonized or destructively distilled in the absence of air. Based on the materials from which tar is derived, it is referred to as wood tar or coal tar. It is more widely used for road work because it is superior.</p><p>There are five grades of roads tar: RT-1, RT-2, RT-3, RT-4 and RT-5, based on their viscosity and other properties.</p><p>RT-1 has the lowest viscosity and is used for surface painting under exceptionally cold weather as this has very low viscosity.</p><p>RT-2 is recommended for standard surface painting under normal Indian climatic conditions.</p><p>RT-3 may be used for surface painting, renewal coats and premixing chips for top course and light carpets.</p><p>RT-4 is generally used for premixing tar macadam in base course.</p><p>RT-5 is adopted for grouting purposes, which has highest viscosity among the road tars.</p><p>The various tests carried out on road tars are:</p><ol><li>Specific gravity test</li><li>Viscosity test on standard tar viscometer</li><li>Equiviscous temperature (EVT)</li><li>Softening point</li><li>Softening point of residue</li><li>Float test</li><li>Water content</li><li>Phenols, percent by volume</li><li>Naphthalene, percent by weight</li><li>Matter insoluble in toluene, percent by weight</li><li>Distillation fraction on distillation upto 200°C, 200°C to 270°C and 270°C to 330°C</li></ol><p>The properties and requirements for five grades of road tars based on the above test results are given by the ISI are given in below table.</p><div style="overflow:scroll";><table width="0"><tbody><tr><td style="text-align: center;" rowspan="2" width="64">Sl. No.</td><td style="text-align: center;" rowspan="2" width="198">Property</td><td style="text-align: center;" width="76"></td><td style="text-align: center;" colspan="3" width="227">Road Tar Grades</td><td style="text-align: center;" width="76"></td></tr><tr><td style="text-align: center;" width="76">RT-1</td><td style="text-align: center;" width="76">RT-2</td><td style="text-align: center;" width="76">RT-3</td><td style="text-align: center;" width="76">RT-4</td><td style="text-align: center;" width="76">RT-5</td></tr><tr><td style="text-align: center;" rowspan="2" width="64">1</td><td style="text-align: center;" rowspan="2" width="198">Viscosity by standard tar viscometer (10 mm)</p><p>(a) at temperature, °C</p><p>(b) viscosity range, seconds</td><td style="text-align: center;" width="76"> </p><p>35</td><td style="text-align: center;" width="76"> </p><p>40</td><td style="text-align: center;" width="76"> </p><p>45</td><td style="text-align: center;" width="76"> </p><p>55</td><td style="text-align: center;" width="76"> –</td></tr><tr><td style="text-align: center;" width="76">33-55</td><td style="text-align: center;" width="76">30-55</td><td style="text-align: center;" width="76">35-60</td><td style="text-align: center;" width="76">40-60</td><td style="text-align: center;" width="76">–</td></tr><tr><td style="text-align: center;" width="64">2</td><td style="text-align: center;" width="198">Equiviscous temperature (EVT) range, °C</td><td style="text-align: center;" width="76">32-36</td><td style="text-align: center;" width="76">37-41</td><td style="text-align: center;" width="76">43-46</td><td style="text-align: center;" width="76">53-57</td><td style="text-align: center;" width="76">63-67</td></tr><tr><td style="text-align: center;" width="64">3</td><td style="text-align: center;" width="198">Softening point, °C</td><td style="text-align: center;" width="76">–</td><td style="text-align: center;" width="76">–</td><td style="text-align: center;" width="76">–</td><td style="text-align: center;" width="76">–</td><td style="text-align: center;" width="76">45-50</td></tr><tr><td style="text-align: center;" width="64">4</td><td style="text-align: center;" width="198">Specific gravity range at 27°C</td><td style="text-align: center;" width="76">1.16-1.26</td><td style="text-align: center;" width="76">1.16-1.26</td><td style="text-align: center;" width="76">1.18-1.28</td><td style="text-align: center;" width="76">1.18-1.28</td><td style="text-align: center;" width="76">1.18-1.28</td></tr><tr><td style="text-align: center;" width="64">5</td><td style="text-align: center;" width="198">Softening point of residue, °C Max.</td><td style="text-align: center;" width="76">48</td><td style="text-align: center;" width="76">50</td><td style="text-align: center;" width="76">52</td><td style="text-align: center;" width="76">54</td><td style="text-align: center;" width="76">56</td></tr><tr><td style="text-align: center;" width="64">6</td><td style="text-align: center;" width="198">Water content, percent by weight, Max.</td><td style="text-align: center;" width="76">0.5</td><td style="text-align: center;" width="76">0.5</td><td style="text-align: center;" width="76">0.5</td><td style="text-align: center;" width="76">0.5</td><td style="text-align: center;" width="76">0.5</td></tr><tr><td style="text-align: center;" width="64">7</td><td style="text-align: center;" width="198">Phenols, percent by volume, Max.</td><td style="text-align: center;" width="76">2</td><td style="text-align: center;" width="76">2</td><td style="text-align: center;" width="76">2</td><td style="text-align: center;" width="76">2</td><td style="text-align: center;" width="76">1</td></tr><tr><td style="text-align: center;" width="64">8</td><td style="text-align: center;" width="198">Naphthalene, percent by weight, Max.</td><td style="text-align: center;" width="76">4</td><td style="text-align: center;" width="76">3.5</td><td style="text-align: center;" width="76">3</td><td style="text-align: center;" width="76">2.5</td><td style="text-align: center;" width="76">2</td></tr><tr><td style="text-align: center;" width="64">9</td><td style="text-align: center;" width="198">Matter insoluble in toluene, percent by weight, Max.</td><td style="text-align: center;" width="76">22</td><td style="text-align: center;" width="76">22</td><td style="text-align: center;" width="76">24</td><td style="text-align: center;" width="76">24</td><td style="text-align: center;" width="76">24</td></tr><tr><td style="text-align: center;" width="64">10</td><td style="text-align: center;" width="198">Distillation fractions, percent by weight (g per 100 g) distilling:</p><p>(a) upto 200°C, Max.</td><td style="text-align: center;" width="76"> </p><p>0.5</td><td style="text-align: center;" width="76"> </p><p>0.5</td><td style="text-align: center;" width="76"> </p><p>0.5</td><td style="text-align: center;" width="76"> </p><p>0.5</td><td style="text-align: center;" width="76"> </p><p>0.5</td></tr><tr><td style="text-align: center;" width="64"></td><td style="text-align: center;" width="198">(b) from 200° to 270°C</td><td style="text-align: center;" width="76">5-12</td><td style="text-align: center;" width="76">2-9</td><td style="text-align: center;" width="76">1-6</td><td style="text-align: center;" width="76">0.5-4</td><td style="text-align: center;" width="76">0-4</td></tr><tr><td style="text-align: center;" width="64"></td><td style="text-align: center;" width="198">(c) from 270° to 300°C</td><td style="text-align: center;" width="76">4-10</td><td style="text-align: center;" width="76">4-8</td><td style="text-align: center;" width="76">3-6</td><td style="text-align: center;" width="76">2-7</td><td style="text-align: center;" width="76">1-5</td></tr><tr><td style="text-align: center;" width="64"></td><td style="text-align: center;" width="198">Total distillation (b+c), Max.</td><td style="text-align: center;" width="76">16</td><td style="text-align: center;" width="76">14</td><td style="text-align: center;" width="76">12</td><td style="text-align: center;" width="76">10</td><td style="text-align: center;" width="76">7</td></tr></tbody></table></div><p><strong> </strong><strong> </strong></p><h1><span style="font-size: 14pt;">Preparation of Tar</span></h1><p>There are three stages in the production of road tar:</p><ul><li>Carbonization of coal to produce crude tar</li><li>Refining or distillation of crude tar</li><li>Blending of distillation residue with distillate oil fractions to give the desired road tar.</li></ul><p> </p><h1><span style="font-size: 14pt;">High-Temperature Carbonization of Coal</span></h1><p>The carbonization or destructive distillation of coal consists essentially of heating a thin layer of coal enclosed in a chamber of refractory brick-work for several hours at temperature about 1000° C. Majority there are two major methods for carbonization, they are:</p><p>a) Carbonization in Coke-ovens</p><p>b) Carbonization in gas-works retorts</p><p> </p><h1><span style="font-size: 14pt;">Carbonization in Coke-Ovens</span></h1><p>A batch of about 16 tons of coal is loaded into a coke-oven.</p><p>Coke oven consists of large thin box lined with brick, 40 feet long, 14 feet high and 1 ½ feet wide.</p><p>The charge of coal is heated for 18 hours at a temperature of 1200° C. Each ton of coal yields 8 gallons of crude tar.</p><p><strong><em> </em></strong><strong> </strong></p><h1><span style="font-size: 14pt;">Distillation of Crude Tar</span></h1><p>The crude tar obtained by the condensation of the vapours emitted from coal in the course of carbonization is subjected to distillation process.</p><p>The distillation or refining of tar is carried out by tar distillers. The process consists, first heating the crude tar to remove water and some light oils (Benzole), then heating further and condensing the heavier vapour in a fractionating column.</p><p>The operation is carried out in two stages:</p><p>In the first stage, the tar passes through the tubes in the cooler part of the furnace at a temperature of 140°C.</p><p>It is then passed to a dehydration chamber where the pressure is released and water and light oil is released.</p><p>The remaining tar is then passed to the second stage of the pipe-still at a temperature of 300°C.</p><p>From pipe-still, tar passes to a chamber at a lower pressure where vaporization takes place.</p><p>The vapours are condensed in a fractionating column which forms fractions of different boiling point ranges.</p><p>The residue which is not distilled is base-tar or pitch.</p><p>In order of increasing boiling points they may be classified as light oil, carbolic oil, naphthalene oil, wash oil, anthracene oil.</p><p><strong> </strong></p><h1><span style="font-size: 14pt;">Blending of Tar-Distillation Fractions to Produce Road Tar</span></h1><p>It is evident from the above that a tar of a suitable viscosity for use on the roads could be left as residue simply by stopping the distillation at the appropriate point.</p><p>Road tar 1 and 2, on the basis of viscosity, having viscosities of 10 to 40 and 40 to 125 seconds at Standard Tar Viscosity (STV) at 30°C.</p><p>Type-A having high softening point is used for surface dressings and base courses. Type-B is used for wearing courses and carpets.</p><p> </p><p><strong>PREPARATION OF ROAD TAR </strong></p><p>Type A = Base tar + Naphthalene oil</p><p>Type B = Base tar + Wash oil + Anthracene oil</p><p> </p><h1><span style="font-size: 14pt;">Chemical Constitution of Tar</span></h1><p>It is estimated that there are over 10,000 compounds in tar. Out of this 300 have been separated. The distillate oils consist largely of aromatic hydrocarbons, with one or more methyl groups attached to the nucleus, with smaller quantities of aromatic hydroxy compounds, paraffinic hydrocarbons and heterocyclic compounds with oxygen, nitrogen or sulphur in the ring.</p><p>Dickinson developed a method called ‘solvent fractionation’ which uses n-hexane, benzene and pyridine as solvents to give five fractions. He divided up in this way tars produced from vertical-retort, horizontal-retort and coke-oven crudes and by measurement of mean molecular weights. Typical structures for the solvent fractions haven been suggested by spectroscopic examination on the basis of molecular weight and C/H ratio.</p><p>The differences in chemical structure between tars from different carbonization processes are reflected in different in their properties. Tars produced by carbonization in coke-ovens or horizontal retorts have more purely aromatic hydrocarbons compared to vertical retorts. Thus, where as in coke-oven tar distillate oils over 90 percent may consist of aromatic hydrocardon of benzene, naphthalene, anthracene and phenanthrene series, similar oils from vertical retort tars contain up to 25% of phenolic material and the same amount of paraffins, this is because temperature reached in coke-ovens and horizontal retorts will be higher than continuous vertical retorts and the vapours evolved during carbonization are in contact with hot coke for a longer period.</p><p>Vertical-retort tars are often referred as low-aromatic tars while coke-oven and horizontal-retort tars as high-aromatic tars. In general, the high-aromatic class is distinguished by wider molecular weight range, higher specific gravity, higher pitch content and low phenolic content.</p><p>The post <a href="https://ishtarcompany.com/articles/bitumen-and-tar/">Bitumen and Tar</a> appeared first on <a href="https://ishtarcompany.com">Ishtarcompany</a>.</p>]]></content:encoded> </item> </channel></rss> If you would like to create a banner that links to this page (i.e. this validation result), do the following:
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