On October 27, 2017, the list of carcinogens released by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily sorted out for reference. Asphalt, occupational exposure to oxidized asphalt and their emissions during roofing were included in the list of Category 2A carcinogens. Occupational exposure to straight run asphalt and its emissions during pavingOccupational exposure to hard asphalt and its emissions during asphalt mastic work are included in the list of Class 2B carcinogens.[2]
In recent years, the most commonly used method is to separate asphalt into saturated component, aromatic componentcolloidandAsphalteneAnd four other components.There is a certain regularity between the content of each component in asphalt and asphalt and technical properties, as shown in the figure.[1]
Obtain the chemical composition and technical properties of asphalt
According to the interpretation of colloidal structure, with the decrease of the content of saturated and aromatic components in the dispersion medium and the increase of the content of protective colloid and dispersed asphaltene, the asphalt changes from sol structure to sol gel structure and even gel structure.The penetration of asphalt technical indicators decreases and the softening point increases.When the proportion of each component in asphalt is coordinated, the best ductility can be obtained.However, the above rules only apply to the asphalt obtained from the same oil source and the same process. For example, the asphalt in Table I is Daqing crude oil, and the asphalt obtained from the same crude oil, different processes, or different crude oil, the same process, or even different crude oil and processes,Although they have similar asphalt component content, their technical property indexes can differ greatly.The reason for these phenomena is that although the chemical components of asphalts obtained from different oil sources and processes can be very similar, the chemical structures of each component are different and the solubility parameters of each component are different.That is, the solubility of each component is different, thus forming different colloidal structures, so their technical properties are also different.[1]
Impact of asphalt and its flue gas onSkin mucosaIt is irritant, phototoxic and carcinogenic.Toxicity of three main asphalts in China: coal tar pitch>shale pitch>Petroleum asphalt, the former two are carcinogenic.The main skin damages of asphalt include:Phototoxic dermatitisThe skin damage is limited to the exposed parts such as face and neck;MelanosisThe skin lesions are usually symmetrically distributed at the exposed parts, in sheet shape, brown dark brown brown black;Occupational acne;Verrucous vegetationAnd thermal burns caused by accidents.In addition, dizziness, dizziness, headache, chest tightness, fatigue, nauseaAnorexiaAnd other systemic symptoms and irritation symptoms of eyes, nose and pharynx.
application area
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In civil engineering, asphalt is a widely used waterproof and anti-corrosion material, mainly used for roof, ground, underground structure waterproof, wood, steel anti-corrosion.Asphalt is also a widely used pavement structural cementing material in road engineering. It can be used to build asphalt pavement with different structures in proportion with mineral materials of different composition. Expressway is widely used.
Industry analysis
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In 2013, the domestic asphalt production was 19.9351 million tons, up 9.71% year on year.Compared with domestic asphalt, the price of imported asphalt is on the high side, thus boosting the demand for domestic asphalt and driving the utilization rate of domestic asphalt capacity.It is expected that the domestic asphalt production will continue to grow in 2014, but with the improvement of demand, the overall surplus situation will be improved.
The upstream of asphalt industry is petrochemical industry, coal, modifier and emulsifier, and the downstream is highway, waterproof building materials, airport construction and municipal engineering road construction.
In the complete petrochemical industry chain, the front-end products of petroleum asphalt are ether, alkane, hydrocarbon, benzene and other major categories of products. Petroleum asphalt, as the back-end product of crude oil processing, can get petroleum glue through coking process.
For the asphalt industry, the impact of the upstream industry is mainly reflected in the fluctuation of crude oil price and the fluctuation of asphalt output and product price caused by the change of crude oil processing capacity.
The mild recovery of the global economy in 2014 will drive the demand for crude oil, and the expansion of the oil pipeline from the Cushing area, the delivery place of U.S. crude oil, to the Gulf of Mexico refinery in the past two years has, to some extent, reduced the local inventory pressure and boosted WTI oil prices.Therefore, despite the impact of the withdrawal of the Federal Reserve from QE and the increase in supply, the center of gravity of international crude oil prices in 2014 is still expected to move up slightly. It is expected that the annual fluctuation range of WTI crude oil prices will be $90-115/barrel, which will support the price of asphalt futures.
In terms of downstream demand, asphalt products are mainly used for laying of highways, municipal roads, bridges, airports and other places, of which the consumption of asphalt for highway construction accounts for 82%.With a certain capacity, the increase of downstream demand will further promote the price growth of asphalt products, and vice versa.
In 2013, some road construction projects were stranded due to the neutral and tight monetary policy and insufficient funding, resulting in limited growth of asphalt demand in 2013.
However, the construction period of road construction is generally 3-4 years, and asphalt pavement is mainly concentrated at the end of construction. Therefore, the demand for asphalt will gradually improve in the last two years of the "12th Five Year Plan".
The industry has broad prospects
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Since the reform and opening up, China's economy has been growing at a high speed, and the construction of highway transportation has made rapid progress.In particular, heavy traffic asphalt and modified asphalt have achieved a qualitative leap from nonexistence to existence, from small to large, and from few to many, making great contributions to road construction in China.
Among them, asphalt pavement maintenance is generally divided into three types: preventive maintenance, corrective maintenance, and emergency maintenance.These three types of maintenance can be selected according to the use of the pavement, and each type of maintenance requires different maintenance methods and equipment.The differences of the three maintenance measures are mainly reflected in the road surface conditions and the length of traffic.Of course, there is no obvious boundary between the three.
Preventive maintenance is to maintain the pavement before it is damaged;Corrective maintenance refers to the repair of local damage to the pavement or the treatment of certain specific diseases;Urgent maintenance is a measure in emergency, for example, pavement burst and serious potholes need to be repaired immediately before they can be opened to traffic.
At present, the asphalt industry in China has entered a rapid stage of large-scale and centralized development, and people are more and more familiar with asphalt, because the amount of asphalt is not only large, but also very extensive. No matter whether it is small streets in the countryside, roads in the city, or high-speed, asphalt can not be separated from the use of asphalt, so asphalt recycling has become a hot topic in people's mouth.
However, compared with the development scale of asphalt and the demand of our domestic market, China's asphalt market is still in a state of oversupply, especially those high-end modified asphalt markets, which also need to be explored by talented people in China. There are many ordinary road asphalt manufacturers in China, but few professional asphalt manufacturers,We should gradually improve professional asphalt manufacturers to make up for the growing demand of professional asphalt market.
history
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Classical period
Archaeological research found that as early as 1200 years ago in the early classical period, people had begun to use natural asphalt as decorations in the production of weapons and tools to add color to sculptures.Especially in Mesopotamia, due to the sufficient content of natural asphalt, asphalt is widely used.Sumerians living there covered their vessels and boats with natural asphalt.In addition, they have begun to use natural asphalt as a binder in clay bricks.
Cross sectional sketch of a magnificent road in Babylon
This is a cross sectional sketch map of a magnificent road in Babylon.The burnt bricks are coated with asphalt, and the top stone slab is laid flat on the asphalt plaster.This magnificent road can be regarded as the pioneer of modern asphalt concrete road.During that thousand years, the application scope of asphalt was expanded, so that in India and Europe near Mesopotamia, natural asphalt was used as a sealing material for baths, boats, canals, toilets and river embankments.In the seventh century BC, the Assyrian Empire and the Babylonian Empire, asphalt has been used in road engineering.At that time, asphalt was used as joint material and coating material to decorate and strengthen the Huadao.Since then, asphalt has been used as a cement like binder to build the Great Wall of China and seal the Hanging Gardens in Babylon.
During the Roman Empire, asphalt was called "Bitumen Iudaicum, Judenpech". In 100 BC, the Roman Avenue in Pompeii used asphalt to fill the joints and coat the outer layer.
the medieval times
After the decline of the Roman Empire, the Middle Ages began.During this period, asphalt lost its former glory.The accumulated experience of using asphalt in the past 1000 years was almost lost, and it was not until the 18th century that people began to learn to use asphalt again.In 1000 AD, the Arabs began to extract bitumen (Bitumen) from natural bitumen.The method is to heat the natural asphalt until the asphalt separates from it.
Different from being used as building materials, asphalt was used for medical purposes in the Inca Empire in Central and South America in the 15th century.On March 22, 1595, Walter Raleigh found a natural asphalt lake on Trinidad Island during his expedition.Until today, people are still building roads with this kind of asphalt from the ground.
Modern times
The cover of Eirini d'Eyriny's doctoral thesis was written in 1721. In 1712, the Greek doctor Eirini d'Eyriny discovered a huge reserve of asphalt ore in Val de Travers, Switzerland.At first, he was only interested in the medical use of asphalt.However, due to the excellent characteristics of asphalt as an engineering material, he finally wrote his dissertation Dissemination sur L'Asphalte ov Ciment Natural in 1721 and began to lay the foundation for the research of modern asphalt technology.In the next three hundred years (1712-1986), I do not know how much asphalt was mined and sold all over the world through the maze like complex mine tunnels located in Val de Traders with a total length of more than 100 kilometers.
In the following time, the colorful application of asphalt was extended to the sealing of roof waterproof layer.At that time, it was very expensive to use asphalt to strengthen the pavement, so that only roads dedicated to the rich could use asphalt to strengthen the pavement.The first time asphalt was used on bridges, it was installed as asphalt pavement on a wooden bridge in Sunderland.
In 1810, in Lyon, asphalt matty paving was first applied.Ten years later, the predecessor of modern asphalt felt was developed in Genoa and successfully applied.Based on extensive attempts, in 1837, asphalt technology was proved to be applicable to highway engineering.In 1839, the method of reusing asphalt by reheating was found in Vienna, the capital of Austria.
In 1838, the first asphalt paved road appeared in Hamburg, Prussia.In 1851, the 78 meter long part of the road from Travers to Paris was paved with asphalt pavement.Only 20 years later, Paris was almost completely covered with asphalt, and soon this situation developed to almost all major cities in Europe.
Later, the tough asphalt mastic was invented;In 1842, in Innsbruck, Austria, pouring asphalt was invented and successfully applied to road construction shortly after.Based on the characteristics of asphalt similar to concrete, the concept of asphalt concrete was proposed by L é on Malo in 1853.In order to obtain sufficient compression ratio, people began to compress asphalt concrete by rolling in 1876.
At the beginning of the 20th century, with the continuous decline in the price of engineering materials, asphalt showed more significance.In 1907, the first asphalt mixture component was put into use in the United States.In 1914, in order to obtain a better refractive index, people first saw a racing track with asphalt pavement in Berlin,
Following the application of asphalt in road engineering, in 1923, asphalt was applied to the sealing of dams.In order to speed up the construction progress and improve the components, the first road completion acceptance inspection was carried out in California in 1924.In order to determine the quality of building materials, many testing procedures were developed in the next few years.These procedures are still effectively used in the research, design and specific construction of traffic engineering today.He developed and invented Ring und Kugel Versuch in 1936, Brechpunkt nach Fraaß a year later, and Marshall Test in 1941.
With special additives, asphalt construction at low temperature has become possible since 1950 (called cold asphalt).In order to determine the appropriate thickness of asphalt structure, in 1959, a non-interference research method by isotope was developed in Austria and successfully verified.
In order to put the airport runway into use as soon as possible, the dry asphalt construction technology appeared in Britain in 1963.Shortly afterwards, in 1968, Mattitane asphalt construction appeared for the first time.In the 1970s, asphalt recycling began in the United States.In order to achieve better sealing effect, asphalt has been used in garbage dump projects since 1979.
Coal tar pitchIt's cokingby-product, i.eTarBlack matter remaining in the distillation kettle after distillation.It is different from refined tar only in physical properties without obvious boundaries. The general division method is to specify that tar with softening point below 26.7 ℃ (cube method) and asphalt with softening point above 26.7 ℃.Coal tar pitch mainly contains anthracene, phenanthrene and pyrene which are difficult to volatilize.These substances are toxic. Due to the different contents of these ingredients, the properties of coal tar pitch are different.The temperature change has a great impact on the coal tar pitch, which is easy to crack in winter and soften in summer.Special smell during heating;When heated to 260 ℃ for 5 hours, the anthracene, phenanthrene, pyrene and other components contained in it will volatilize.
Petroleum asphalt
Petroleum asphaltyescrude oilResidue after distillation.According to the degree of refining, the liquid can be formed at room temperatureSemisolidOr solid.Petroleum asphalt is black and shiny, with high temperature sensitivity.Since it was distilled to over 400 ℃ in the production process, it contains very little volatile components, but there may still be macromolecularhydrocarbonWithout volatilization, these substances are more or less harmful to human health.
Natural asphalt
Natural asphaltIt is stored underground, and some forms ore beds or accumulates on the surface of the crust.Most of the asphalt has been naturally evaporated and oxidized, and generally does not contain any toxins.
Asphalt materials are divided intoAsphaltAnd tar pitch.Asphalt is also divided into natural asphalt and petroleum asphalt. Natural asphalt is the residue of oil seeping out of the surface after long-term exposure and evaporation;Petroleum asphalt is the product obtained by treating the residual oil from refining and processing petroleum with appropriate process.Tar asphalt is coal, wood, etcorganic compoundThe tar obtained from dry distillation is reprocessed.Most of the asphalt used in the project is petroleum asphalt, which is a complex hydrocarbonNonmetalDerivativemixture。Generally, the flash point of asphalt is between 240 ℃~330 ℃, and the ignition point is about 3 ℃~6 ℃ higher than the flash point, so the construction temperature should be controlled below the flash point.
Technical indicators
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density
The mass per unit volume of asphalt sample at the specified temperature, in t/m3.
relative density
The ratio of asphalt mass to water mass of the same volume at the specified temperature.
Penetration
Within the specified temperature and time, the depth of vertical penetration of a standard needle with a certain amount of additional quality into the asphalt sample, expressed in 0.1mm.
Penetration index
An index of temperature sensitivity of asphalt binder, the degree of reaction penetration changing with temperature, and the penetration with different temperatures shall be calculated according to the specified method.
Ductility
The length of the asphalt sample with the specified shape, which is stretched at a certain speed at the specified temperature to the time of breaking, is expressed in cm.
softening point
The asphalt sample is placed in a metal ring with a specified size and quality, placed in water or glycerin, heated at a specified speed, and the temperature when the steel ball sinks to a specified distance is expressed in ℃.
solubility
The content of soluble matter in the specified solvent of asphalt sample, expressed in mass percentage.
Evaporation loss
The mass loss of asphalt sample after heating at 163 ℃ and holding for 5h in a sample dish with an inner diameter of 55mm and a depth of 35mm, expressed in percentage.
flash point
The gas evaporated when the asphalt sample is heated at the specified heating rate in the specified sample container contacts the test flame in the specified method, and the sample temperature at the first instant of burning is expressed in ℃.For viscous asphalt, the sample containerCleveland open cup (COC for short), for liquid asphaltTiger open cup(TOC for short).
Fraser
The temperature at which the asphalt sample film coated on the metal sheet cracks due to cooling and bending under the specified conditions, expressed in ℃.
viscosity
The measurement of resistance or internal resistance formed when the asphalt sample flows under specified conditions, also known as viscosity.
main products
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Petroleum asphalt
Petroleum asphalt is a product of crude oil processing. It is a black or dark brown viscous liquid, semi-solid or solid at room temperature, mainly containingchloroformThe properties and composition of the hydrocarbon and non hydrocarbon derivatives of petroleum vary with the source of crude oil and production methods.The main components of petroleum asphalt are oil, resin andAsphaltene。It also contains 2%~3% pitch carbon, carbonlike substances and wax.Oil and resin in asphalt can be soakedAsphaltene。The structure of asphaltAsphalteneAs the core, it absorbs part of resin and oil to form micelles.
Product performance
Petroleum asphalt is black and shiny, with high temperature sensitivity.Petroleum asphalt can be classified according to the following systems:
Production method
(1) Distillation method: crude oil is separated by regular pressure distillationgasoline, kerosenediesel oilAnd then through vacuum distillation (residual pressure 10~100mmHg)Distillate oilWhen the remaining residue meets the specification of road asphalt, asphalt products can be directly produced. The obtained asphalt is also called straight run asphalt, which is the main method for producing road asphalt.
(2) Solvent precipitation method: non-polar low molecularalkaneSolvents have different solubility for each component in vacuum residue, and component separation can be realized by using the difference in solubility, so components adverse to asphalt properties can be removed from vacuum residue to produce asphalt products that meet the specification requirements, which is called solvent precipitation method.
(3) Oxidation method: air is blown into vacuum residue or deoiled asphalt under a certain range of high temperature to change its composition and performance. The product obtained is called oxidized asphalt.The vacuum residue will vaporize under the action of high temperature and blowing air, and dehydrogenation, oxidation and polymerization will occur at the same timecondensationAnd a series of reactions.This is a very complex comprehensive reaction process with multi-component interaction, not justoxidation reaction However, it is customarily called oxidation method and oxidized asphalt, and also called air blowing method and air blowing asphalt.
(4) Blending: The blending method for asphalt production initially refers to the re blending of four components of asphalt composed of the same crude oil in the proportion required by the quality requirements. The resulting product is called synthetic asphalt or reconstructed asphalt.With the development of technology, the source of blending components has been expanded.For example, the residues or components from the primary and secondary processing of the same crude oil or different crude oils and various industrial waste oils can be used as blending components, which reduces the dependence on oil source selection in asphalt production.With the increasing shortage of crude oil suitable for asphalt production, the flexibility and economy of blending method are increasingly valued and widely used.
(5) Emulsification method: asphalt and watersurface tensionThe difference is very big, and they will not be miscible with each other at room temperature or high temperature.However, when asphalt is subjected to high-speed centrifugation, shearing, pounding and other mechanical actions, it becomes a particle with a particle size of 0.1~5 μ m and is dispersed to the surface containing surfactant（Emulsifier——The emulsifier can be adsorbed on the surface of asphalt particles directionally, thus reducing theinterfacial tensionSo that asphalt particles can form stableDispersion system, this isOil in waterEmulsion.The dispersion system is tan, and the asphalt isdispersed phase, water iscontinuous phaseIt has good fluidity under normal temperature.In a sense, emulsified asphalt is "diluted" with water, thus improving the fluidity of asphalt.
(6) Modified asphalt: many changes have taken place in modern roads and roads: the traffic flow and driving frequency have increased sharply, the axle load of freight cars has increased continuously, and one-way driving in separate lanes is generally implemented, which requires further improvement of the anti mobility of the pavement, that is, the ability to resist rutting under high temperatures;Improve flexibility and elasticity, that is, the ability to resist cracking at low temperatures;Improve wear resistance and prolong service life.Large span prestressed roof slab is widely used in modern buildings, which requires roofWaterproof materialAdapt to large displacement, more resistant to harsh high and low temperature climate conditions, with better durability, self-adhesive, convenient construction and reduced maintenance workload.These changes in the service environment pose serious challenges to the performance of petroleum asphalt.The modification of petroleum asphalt to meet the above stringent requirements has attracted people's attention.After decades of research and development, a wide variety of modified road asphalt, waterproof coiled materials and coatings have emerged, showing a certain engineering practical effect.However, in view of the fact that the price of the modified material is usually 2~7 times higher than that of ordinary petroleum asphalt, users have not yet fully grasped the engineering performance of the material, and the production of the modified asphalt increases slowly.Modified road asphalt is mainly used for the pavement of airport runways, waterproof bridge decks, parking lots, sports grounds, heavy traffic pavements, intersections, road turns and other special occasions.The application of modified asphalt to the maintenance and reinforcement of highway network in Europe has greatly promoted the widespread application of modified road asphalt.ModificationAsphalt waterproof rollAnd coatings are mainly used for waterproof engineering of high-grade buildings.along withScientific and technological progressAnd the development of economic construction will further promote the development of modified asphalt varieties and production technology.The type and preparation technology of modified asphalt depend on the type and amount of modifier and the composition and nature of base asphalt (i.e. raw asphalt).Due to the wide variety and different forms of modifiers, various types of modifiers have been evaluated over the years and corresponding formulas and preparation methods have been developed to form uniform engineering practical materials with petroleum asphalt, but most of the engineering practical modified asphalt belongs to patented technology and patented products.
Main purpose
It is mainly used as infrastructure materials, raw materials and fuels, and its application scope includes transportation (roads, railways, aviation, etc.), construction, agriculture, water conservancy engineering, industry (mining, manufacturing), civil and other sectors.
Packaging and storage
Asphalt may need to be stored in storage tanks during production and use. If properly treated, asphalt can be reheated for a long time at a higher temperature without serious damage to its performance.However, if the asphalt is exposed to oxygen, light and overheating, it will harden. The most obvious sign is that the softening point of the asphalt increases, the penetration decreases, and the ductility deteriorates, which will result in the loss of asphalt performance
Heating output
Asphalt is stored in large storage tanks. When it is used for output, the asphalt in the storage tank needs to be heated to improve the fluidity of asphalt, so that it can be exported smoothly and quickly.Heat source required for heating output is generally heat transfer oil.According to the introduction of Petrochemical Technology Promotion Center, the traditional heating method has the following disadvantages:
1. The heating process is not economical.When only a small amount of asphalt needs to be poured out, the asphalt in the whole tank should also be heated. The amount of heated asphalt is several times of the amount used this time, making a large amount of heat transfer oil useless.
2. The asphalt temperature in each part of the tank is uneven.The temperature of asphalt near the heater is higher, and the temperature of asphalt far away from the heater is lower, which seriously affects the flow of oil.
3. It affects the quality of asphalt.Repeated heating of asphalt in the tank will produce a large number of fine decomposition products, which will have a certain impact on the asphalt color quality and increase the cost of post-treatment.
Local heating technology: after the heat transfer oil enters the "local fast heater", the asphalt in the asphalt tank is heated locally and quickly. How much asphalt is needed and how much asphalt is heated. The whole tank is not required to be heated repeatedly. At the same time, the asphalt output is faster while saving energy.
Petrobitumen
The flow deformation of asphalt pavement is the most common damage phenomenon of asphalt pavement in the world.According to statistics, about 80% of pavement maintenance statistics are caused by deformation and damage caused by rutting.Through engineering practice, it is found that the modified asphalt added with rock asphalt has greater advantages in high temperature stability, and can well solve the rutting and early disease of high-grade asphalt pavement caused by large traffic volume, overweight and overload.
Rock asphalt is a kind of asphalt produced by the comprehensive action of heat, pressure, oxidation, catalyst, bacteria and so on after hundreds of millions of years of deposition and change of oil.It is commonly used as matrix asphalt modifier.The physical properties of rock asphalt are close to "coal".
The proven natural rock asphalt mineral resources in China are mainly distributed in Xinjiang, Qinghai and Qingchuan of Sichuan.Qingchuanyan asphalt mine is located in the Longmen Mountain area in northern Sichuan, which is known as the Land of Abundance in China. The initially proved reserves are more than 3 million tons, and the prospective reserves are 10 million tons. It is praised by experts as "a rare natural asphalt ore body in China and even the world", and its reserves rank first in China.The natural rock asphalt in northern Sichuan is mainly composed of asphaltene with molecular weight up to 10000, and its chemical composition is 81.7% carbon, 7.5% hydrogen, 2.3% oxygen, 1.95% nitrogen, 4.4% sulfur, 1.1% aluminum, 0.18% silicon and 0.87% other metals.Among them, the content of carbon, hydrogen, oxygen, nitrogen and sulfur is relatively high, and almost every asphaltene macromolecule contains polar functional groups of the above elements, which makes it produce extremely strong adsorption force on the rock surface.
Research and development achievements of domestic super asphalt
On May 25, 2014, the Chinese army carried out the runway test flight of the third generation fighter plane on the Zhengmin Expressway for the first time.Sun Xiaowei, a military expert of the Yangtze Evening News, explained that the requirements for the runway of the expressway for aircraft takeoff and landing are very strict, which is different from the standard for laying ordinary expressways.One of the key points is the "material" of the expressway. A special layer of improved asphalt concrete is paved on the top of Zhengmin Expressway.Reporters fromSoutheast UniversityAccording to the interview, this "super asphalt", which can withstand 300 ℃ high temperature and 30 ℃ low temperature, was developed by Southeast University in conjunction with Jurong Ningwu Technology Development Company.
"Super" asphalt
Capable of withstanding 300 ℃ high temperature, acid and alkali resistant, elastic
"Zhengmin Expressway (from Zhengzhou to Minquan) is an important communication channel in the expressway network of Henan Province, and the technical standard of two-way four lane expressway is adopted for the whole line. In 2008, the construction of Zhengmin Expressway was started, with Zhang Zhanjun, a postdoctoral fellow of Southeast University, as the general manager. The domestic 'super asphalt' used for laying this expressway was developed and manufactured by Jiangsu."Zhu Jianshe, a researcher who is assistant president of Southeast University, told reporters that this asphalt is called "epoxy asphalt".
Different from common asphalt, epoxy asphalt is made by adding epoxy resin into asphalt and reacting with curing agent to make asphalt have high strength and toughness and little deformation at high and low temperatures.This material looks simple, as long as asphalt and epoxy resin are mixed in a certain proportion.However, it is more difficult to get the proper proportion of materials than to climb to the sky.Scientific research is almost carried out in a blank."Just like the human blood type, we have to find a matching one for blood transfusion, asphalt and epoxy resin, which obviously cannot be fused with each other, so the difficulty is here.
How good is the epoxy asphalt independently developed by Jiangsu?Zhu Jianshe introduced that in the repeated laboratory, the domestic epoxy asphalt remained unchanged at a high temperature of 300 ℃ and a low temperature of minus 30 ℃. "The temperature of the gas emitted by the jet aircraft when taking off and landing reached 1000 ℃, which can instantly 'melt' ordinary asphalt." This asphalt is also corrosion resistant,"We have done experiments to soak epoxy asphalt in acid, alkali and salt for more than a month, and it has almost no change." This kind of asphalt is also characterized by toughness. "In the past, our roads were mostly rigid. Driving hard, the noise was loud, and the wear of wheels and roads was serious.The new asphalt has a certain elasticity, providing a buffer force for heavy aircraft when taking off and landing, and the aircraft is not easy to wear. "Another key point is that this material is absorbent, which can penetrate the accumulated water caused by rain and snow.
R&D Road
American asphalt paved on the Second Yangtze River Bridge is half as cheap as domestic asphalt
However, before 2006, the manufacturing technology of this environment-friendly asphalt with high temperature and low temperature resistance and pressure resistance was monopolized by the United States, and the technology was blocked.In 2001, the team led by Huang Wei, an academician of the Chinese Academy of Engineering and professor of Southeast University, used the American "epoxy asphalt" when paving the Second Yangtze River Bridge. If ordinary asphalt was used for paving, cracks and slippage would easily occur on the bridge deck in the season of large temperature difference, and the team would fall into the strange circle of "repeated damage and repair, repeated repair and repair"."But the price of epoxy asphalt in the United States is so high that it costs more than 70000 yuan per ton. After the second bridge was paved, Professor Huang Wei said that China must develop its own epoxy asphalt pavement materials and complete technology, and the core technology of national major project construction must be mastered by our Chinese people!"
In 2001, Southeast University established the "Project Team for New Epoxy Asphalt Manufacturing Equipment and Engineering Application", with Professor Huang Wei as the team leader and researcher Zhu Jianshe as the main person in charge. Jurong Ningwu was selected to carry out industry university research cooperation."Professors from Jiaotong College, School of Chemistry and Chemical Engineering, and School of Automation, Southeast University, and technicians from Ningwu Science and Technology have worked together for more than six years, and finally mastered the manufacturing method of this special asphalt." "The American one costs more than 70000 tons, and our price is only half of it, more than 30000."
Main characteristics
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Bitumen is very viscous but fluid.In April 2014, the longest experiment in the world finally came to fruition, but the Australian physicist Mason, who was expecting to witness the experiment for more than 50 years, had passed away for 8 months. At the end of his life, the professor was also unable to witness the experimental results for decades.
In the 1920s, in order to show students that solids can also flow like liquids, Professor Parnell of the Department of Physics, Queensland University, Australia, conducted an asphalt dripping experiment.Asphalt has two forms, solid and liquid, under different conditions. It is a kind of viscous material commonly used for waterproofing. Its viscosity is 230 billion times that of water. The solid can resist hammering without deformation.But a funnel can let solid asphalt flow.
In the experiment, the researchers put the asphalt into a glass funnel. Through the extrusion, the solidified asphalt will flow down like a liquid, but this process is very slow.How slow does asphalt flow?Due to plate drift, the Australian continent moves about 6cm northward every year, and the speed of asphalt solidification flow is 10 times slower than the movement of the earth plate.
Mason, a physicist, took over the custody after the death of Parnell. Before that, there had been five drops of asphalt.Meston could have witnessed the longest experiment in the world for three times. However, by God's whim, Meston missed three fleeting dripping moments by mistake. Until his death, he could not see the experimental results waiting for decades.
It is reported that in 1977, Mason waited for the asphalt for a whole weekend when it was about to drop, but the asphalt fell when he came home exhausted.In 1988, a drop of asphalt was nearly dripping, but Mason left the room for only 5 minutes to have a cup of coffee and missed this rare moment again.In 2000, in order to fully record the moment of asphalt dripping, Mason installed a webcam so that he could see and record the moment of asphalt dripping even when he was far away in the UK.However, the tropical storm caused a power failure for 20 minutes. By the time the power was restored, the asphalt that Mason had waited for more than 10 years had fallen.In 2014, the ninth drop of asphalt finally dripped again, but Professor Meston could no longer see the moment when it fell.In August 2013, Professor Meston died of stroke at the age of 78.
After the death of Professor Meston, this experimental instrument was kept by White of Queensland University.White said the experiment could last at least another 80 years.At the rate of 2014, the next drop of asphalt will fall in 2027.It is reported that this experiment was recognized by Guinness World Records as the longest lasting experiment in the world. It also won the Ig Nobel Prize in 2005 - "Research is to make you laugh and think".
Main hazards
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Asphalt is a brownish black organic gelling substance, including natural asphalt, petroleum asphalt, shale asphalt andcoal tarThere are four kinds of asphalt.The main components areAsphalteneandresinFollowed by high boiling mineral oil and a small amount of oxygen, sulfur and chlorinechemical compound。Glossy, liquidSemisolidOr solid state, brittle at low temperature,CohesivenessAnd good corrosion resistance.IfclothesIt can be diluted if it is accidentally stained with asphaltsodium hydroxideclean.
Coal tar pitch is the most harmful of the four kinds of asphalt.stayelectrodeA large amount of asphalt smoke shall be discharged during the production of baking furnace.Because asphalt containsFluorescent substanceSubstance, including carcinogens3,4-benzopyreneUp to 2.5% - 3.5%, volatilized with flue gas during high-temperature treatment.Asphalt smoke is yellow gas, in which tar fine particles are tested.The content of 3,4 benzopyrene in asphalt flue gas discharged from electrode baking furnace is determined to be 1.3-2mg/m3.
Asphalt smoke and dust can cause poisoning through respiratory tract and contaminated skin, resulting in dermatitis, blurred vision, conjunctivitis, chest tightness, abdominal disease, palpitations, headache and other symptoms.Scientific tests have proved that 3,4 benzopyrene contained in asphalt and asphalt smoke is the main cause of skin cancer, lung cancer, stomach cancer and esophageal cancer.
Living in the air polluted by asphalt is easy to reduce immunity.
The main components of asphalt and its flue gas are phenols, compounds, anthracene, naphthalenepyridineIt is irritant to the skin and mucous membrane, coated with 30% coal tar pitchtolueneAfter the solution is applied for 3 times, the local area shows hyperkeratosis and rhagade after inflammation.
Bitumen and its contentsanthracene、phenanthrene、pyridineIsomeric is a phototoxic substance, which can causePhotochemical reaction。The photochemical reaction caused by asphalt is the photochemical reaction of asphalt under aerobic conditions through the action of light energy, reflecting the generatedFree radicalPeroxide causes cell damage, so it is a non immune disease.
Animals reproduce asphalt cancer.In our country, asphalt can also cause skin cancer in mice.Most of them are phosphorous epithelial carcinoma, and a few are keratomastoid tumors.people say thatkeroseneAsphalt has the strongest carcinogenicity, while natural asphalt has no carcinogenicity, but opinions on the carcinogenicity of petroleum asphalt are still inconsistent.
The effect of coal tar pitch coating on animal weight growth is more obvious than that of petroleum asphalt, and the harm of coal tar pitch coating on animals is greater than that of smoke inhalation.It suggests that coal tar pitch has certain effects on animalsSystemic effectsThe extent of its effect is related to the absorption pathway.
Skin damage
Workers are paving asphalt roads
1. Solar dermatitis This disease is often caused by contact with asphalt dust or smoke and exposure to sunlight.The disease can occur from a few minutes to 1-2 days (mostly hours) after sun exposure.The skin lesions are limited to the exposed parts such as the face and the back of the neck, especially the eyelids and cheekbones.The skin lesions were sunburn type, which showed clear red fresh erythema, often accompanied by edema, blisters, bullae, even erosion and exudation in severe cases.The skin lesions reach the peak within 1-2 days, and generally stop contact for 3-5 days, and rapidly subside, with mild bran like scales attached locally, often secondary to temporary mild pigmentation.Consciously burning pain, some mild itching.
2. Melanosis This disease is usually symmetrically distributed on the exposed parts of the face and neck, and also affects the forearm.It is particularly prone to occur around the eyes, the temporal part, the hairline and inner horn of the forehead, the cheek beside the nose and around the mouth.The skin lesions are mostly lamellar, dark in color, brown dark brown brown black, sometimes slightly maroon or lilac.Its size and shape are different, and most of its edges are fuzzy.The pigmentation of the forearm is often centered on the pores, and the affected pores are slightly keratinized;Sometimes the pale brown with grayish purple pigmentation spots alternate with the normal skin and become cloudy.It often has a history of repeated attacks of asphalt phototoxic dermatitis, and is often accompanied by asphalt acne.The disease is a chronic process.Sunshine aggravates the disease.Disengagement is expected to improve, leading to recovery.
3. The main manifestations of occupational acne caused by acne asphalt are blackhead acne, broken hair and folliculitis mound diagnosis.The disease tends to occur in direct contact.
Parts, such as the face, back of fingers, back of hands and forearms, also often affect the parts of clothes and trousers polluted by asphalt, such as the thigh extension, occasionally on the trunk.Blackhead acne refers to the black spots in the enlarged pores, under which there are often small white indurations.Blackheads caused by asphalt are generally thicker than those caused by chloride, and are also scattered, mainly located on the face, especially between the temporal, eyebrows, and both sides of the nose. The eyelids and auricles can also be affected.The red follicular papules are follicular papules, with yellow white pustules on the top, which may develop into furuncles, induration and scars in severe cases;Usually scattered on the face and forearm.The vellus hair is broken and thickened, and the local pores are commonly expanded with slight keratosis, mainly distributed on the back of the first finger and the radial extension of the forearm.The onset of this disease is not restricted by age.Conscious symptoms are absent, sometimes accompanied by dryness, and there is pain when folliculitis and furuncles appear.
4. Verrucous vegetations usually occur on the back of the hand, wrist and face, and can also affect the scrotum.It is similar to flat wart, with skin color of light brown brown flat papules on the surface, needle cap or mung bean size, round or irregular, rough or smooth surface, and clear boundary.Scattered or densely distributed.No symptoms or slight itching.The longer the general length of service, the higher the incidence and the more skin lesions.Verrucous vegetations can disappear naturally.It may develop into skin cancer.
5. Burns are mostly caused by splashing, slipping and other accidents.The hot liquid asphalt causes thermal burns to the skin.The clinical manifestations were similar to those of general thermal burns.The skin surface can be covered with black asphalt, which is tightly adhered to the wound surface and is not easy to remove.
Eye, nose and pharynx symptoms
The damage of asphalt dust and smoke to the eyes is mainly blepharoconjunctivitis, sometimes accompanied by superficial spotted keratitis, and pterygium accounts for a certain proportion of those who have worked longer.Nasopharynx is often dry and hot, which can also cause rhinitis, pharyngitis, etc.
Systemic symptoms
After smelling the smell of asphalt, there may be dizziness, headache, chest tightness, fatigue, nausea or cough, palpitations, tinnitus and other discomfort, especially in the hot sun.The symptoms of disengagement (after the following shift) are often relieved quickly.Severe cases (such as severe phototoxic dermatitis) may be accompanied by fever.
