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1、Ch5 Bituminous Materials,5.1 Types of asphalt5.2 Petroleum asphalt5.3 Properties of asphalt5.4 Asphalt grades5.5 Spray applications5.6 Testing,5.1 Types of asphalt,Bitumen is a solid，semisolid，or viscous cementitious material，natural or manufactured，and composed principally of various mixtures of co
2、mplex hydrocarbons(烃,碳氢化合物).Features of bitumenCompletely soluble in carbon disulfide(CS2)NonvolatileSoften when heated,沥青分类,沥青材料分为地沥青和焦油沥青两大类。地沥青又分为天然沥青和石油沥青天然沥青是石油渗出地表经长期暴露和蒸发后的残留物；石油沥青是将精制加工石油所残余的渣油，经适当的工艺处理后得到的产品。焦油沥青是煤、木材等有机物干馏加工所得的焦油经再加工后的产品。工程中采用的沥青绝大多数是石油沥青，石油沥青是复杂的碳氢化合物与其非金属衍生物组成的混合物。通常沥青闪点
3、在240330之间，燃点比闪点约高36度，因此施工温度应控制在闪点以下。,地沥青,石油沥青,沥青膏,焦油沥青,焦油,天然沥青,天然沥青,岩石沥青,乳化沥青,稀释(石油)沥青,氧化沥青,慢凝,中凝,快凝,沥青（烃,碳氢化合物）,Uses of bituminous materials,Bitumens possess a number of properties that make them useful in the constructionability to adhere to solid particles impermeability or water resistanceUses o
4、f bituminous materials roadways pavementsmany construction productssuch as roofing felt,caulking compound,waterproofing compounds,wallboard,building paper,paints,etc.waterproof coatings for walls and below-grade structures,5.1.1 Tars and pitches,Tars,along with pitches,are the products of distillati
5、on of materials such as wood,coal,and shale.When these materials undergo destructive distillation,the resulting condensate冷凝物 is tarFurther processing yields a solid or semisolid residue known as pitch,Tar 焦油Generally by-product of coke(from coal)productionWhen coal is heated in coke ovens,it is red
6、uced to coke.The gases(vaporized oils)generated during the process are collected from the oven and refined.The distillation of lighter oils produces tar.焦油是煤炭在焦化过程中产生的。其产量约占装炉煤的3%4%，在常温常压下其产品呈黑色粘稠液状，密度通常在0.95-1.10g/cm3之间，焦油又称煤焦油。,Tar pitches 焦油沥青,Tar pitches are used for built-up roofing and waterpr
7、oofing of underground and aboveground constructionsuch as foundations，retaining walls，dams，and bridgesAboveground structures experience great fluctuations in environmental conditions，and waterproofing compounds should be able to withstand these changes without becoming brittle or too soft,5.1.2 Asph
8、alts,Asphalts are cementitious materials in which the predominant constituent materials are bitumens.Natural deposits or petroleum asphaltThe consistency of asphalts varies widely from solid to semisolid at normal temperature,The natural deposits of asphalts are of two types：,Natural rock asphaltsDe
9、posits of sandstone or limestone filled with asphaltsNative asphalts or lake asphaltsLake Trinidad特立尼达岛，West Indies(a 110-acre lake containing about 40 percent bitumen mixed with water,fine siliceous silt,clay,and organic matter);Bermudez，Venezuela(lake asphalt containing about 65 percent bitumen),T
10、rinidad Lake Asphalt,特立尼达岛 特立尼达和多巴哥的主岛。与委内瑞拉东北部海岸相望，最近处仅11公里。面积4，828平方公里。人口101.6万（1980）。1532年起沦为西班牙殖民地，后被英、荷、法侵占，1802年成为英国殖民地。1962年独立后成为该国领土的主要部分。岛上北部、中部、南部有三条大致东西向的低山脉，最高峰为北部山脉的阿里波山（940米）。向南地势降低，大部分地方为不超过150米的低平原。沿海多沼泽。热带气候，炎热潮湿，有干季。河流短促、经济以石油工业为主。南部石油带（面积约2，000平方公里）及沿海大陆架富藏石油和天然气，西南部有闻名世界的沥青湖。炼油能力
11、超过开采能力，主要炼油中心和石油输出港是皮埃尔角、福廷角和拉布雷阿，均在西南部帕里亚湾岸。农作区主要分布在中部平原，甘蔗为传统经济作物。,*5.2 Petroleum asphalt,Petroleum asphalts are classified into four types：Asphalt cementsCutback asphaltsEmulsified asphaltsAir-blown asphalts,Usages of petroleum asphalts,Petroleum asphalts are used in construction of flexible pave
12、mentsroof construction(asphalt shingles,rolled roofing,and built-up roofing),for insulation(electrical insulation and building paper)waterproofing(sprays,paints,and bituminous fabrics)canal lining seal subgrades against the migration of waterJoint seals,*5.2 Petroleum asphalt,Petroleum asphalts are
13、classified into four types：Asphalt cementsCutback asphaltsEmulsified asphaltsAir-blown asphalts,5.2.1 Asphalt Cement,Asphalt cement is very sticky and highly viscous,especially prepared with the quality and consistency required in the manufacture of asphalt pavements(hot-mix pavements).It is obtaine
14、d after separation of lubricating oils from crude petroleum.,Properties of asphalt cement,It possesses excellent binding properties and adheres very well to aggregate particles.when used in pavement construction it is necessary to heat both the asphalt cement and the aggregates prior to mixingsuperi
15、or waterproof qualitiesPavement built using paving asphalt is waterproof and resistant to many types of chemical attack.,*5.2 Petroleum asphalt,Petroleum asphalts are classified into four types：Asphalt cementsCutback asphaltsEmulsified asphaltsAir-blown asphalts,5.2.2 Cutback Asphalts,Two types of a
16、sphalt are available in liquid form:cutback asphalt emulsified asphaltCutback asphalt-is asphalt cement that is liquefied by blending with petroleum solvents(called diluents).,Cutback asphalt are divided into three types,Slow-curingMedium-curingRapid-curing,Slow-curing cutback asphalt,Slow-curing cu
17、tback asphalt is asphalt cement blended with oils of low volatility，such as diesel oil 柴油.Its viscosity value is low and it hardens very slowly.It is used for cold laid pavement bases.,Medium-curing cutback asphalt,Medium-curing cutback asphalt is obtained by blending asphalt cement with kerosene-煤油
18、 type diluents of medium volatility.It hardens faster than the slow-curing and slower than the rapid-curing type.Used for cold-laid pavement bases(plant mixed and mixed in place)and surface treatments,Rapid-curing cutback asphalt,Rapid-curing cutback asphalt is asphalt cement blended with naphtha or
19、 gasoline-汽油 type diluents of high volatility.The diluents in rapid-curing asphalt evaporate quickly.Used primarily in mixed-in-place pavement mixes and surface treatments.,*5.2 Petroleum asphalt,Petroleum asphalts are classified into four types：Asphalt cementsCutback asphaltsEmulsified asphaltsAir-
20、blown asphalts,5.2.3 Emulsified Asphalt,Emulsified asphalt is composed of asphalt cement and water that contains a small amount of an emulsifying agentSoapswater-soluble chemicalsfine clay,乳化沥青 乳化沥青是将通常高温使用的道路沥青，经过机械搅拌和化学稳定的方法（乳化），扩散到水中而液化成常温下粘度很低、流动性很好的一种道路建筑材料。可以常温使用，且可以和冷的和潮湿的石料一起使用。当乳化沥青破乳凝固时-还原
21、为连续的沥青并且水分完全排除掉，道路材料的最终强度才能形成。、在众多的道路建设应用中，乳化沥青提供了一种比热沥青更为安全、节能和环保的系统，因为这种工艺避免了高温操作、加热和有害排放。乳化沥青主要用于道路的升级与养护，如石屑封层，还有多种独特的、其它沥青材料不可替代的应用，如冷拌料、稀浆封层。乳化沥青亦可用于新建道路施工，如粘层油、透层油等。,*advantages of emulsified asphalt,emulsified asphalt can be applied during damp weather and with aggregates that are cold or ho
22、tthe quantity of materials applied is controlled automatically because any excess(water)will drain into the subgradesaving energyThe use of emulsified asphalt also eliminates the use of fuel required to heat and dry the aggregates in the asphalt cement mixturesreduces energy requirements through red
23、uction or elimination of petroleum distillates used in cutback asphalts.,*disadvantage of emulsified asphalt,pollutionbecause the asphalt is suspended in water,it is susceptible to being washed off a road surface by rainwater if not sufficiently cured.The unbroken emulsions may be carried into strea
24、ms,causing ground contamination.,*5.2 Petroleum asphalt,Petroleum asphalts are classified into four types：Asphalt cementsCutback asphaltsEmulsified asphaltsAir-blown asphalts,5.2.4 Blown Asphalt,Blown asphalt is obtained by blowing air through the semisolid residue obtained during the later stages o
25、f the distillation processProperties relatively firm in consistency Ductileweather resistant and can withstand temperature changes very well,Usages of Blown asphalts,Blown asphalts use in the manufactureroofing materialswaterproof paints joint fillers(for concrete pavements)undersealing old，rigid pavements mineral rubber,
