土木工程材料第五章1

Ch5 Bituminous Materials5.1 Types of asphalt5.2 Petroleum asphalt5.3 Properties of asphalt5.4 Asphalt grades5.5 Spray applications5.6 Testing 5.1 Types of asphaltBitumen is a solid，semisolid，or viscous cementitious material，natural or manufactured，and composed principally of various mixtures of complex hydrocarbons (烃烃, 碳氢化合物碳氢化合物).Features of bitumenlCompletely soluble in carbon disulfide (CS2)lNonvolatilelSoften when heated沥青分类沥青分类沥青材料分为地沥青和焦油沥青两大类。沥青材料分为地沥青和焦油沥青两大类。l地沥青又分为天然沥青和石油沥青地沥青又分为天然沥青和石油沥青l天然沥青是石油渗出地表经长期暴露和蒸发后的残留物；天然沥青是石油渗出地表经长期暴露和蒸发后的残留物；l石油沥青是将精制加工石油所残余的渣油，经适当的工艺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。处理后得到的产品。l焦油沥青是煤、木材等有机物干馏加工所得的焦油焦油沥青是煤、木材等有机物干馏加工所得的焦油经再加工后的产品。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。通常沥青闪点在成的混合物。通常沥青闪点在240330之之间，燃点比闪点约高间，燃点比闪点约高36度，因此施工温度，因此施工温度应控制在闪点以下。度应控制在闪点以下。 地沥青地沥青石油沥青石油沥青沥青膏沥青膏焦油沥青焦油沥青焦油焦油天然沥青天然沥青天然沥青天然沥青岩石沥青岩石沥青乳化沥青乳化沥青稀释稀释(石油石油)沥青沥青氧化沥青氧化沥青慢凝慢凝中凝中凝快凝快凝沥青（烃沥青（烃, 碳氢化合物）碳氢化合物）Uses of bituminous materialsBitumens possess a number of properties that make them useful in the constructionlability to adhere to solid particles limpermeability or water resistanceUses of bituminous materials lroadways pavementslmany construction productslsuch as roofing felt, caulking compound, waterproofing compounds, wallboard, building paper, paints, etc. lwaterproof coatings for walls and below-grade structures5.1.1 Tars and pitchesTars, along with pitches, are the products of distillation of materials such as wood, coal, and shale.When these materials undergo destructive distillation , the resulting condensate冷凝物冷凝物 is tarFurther processing yields a solid or semisolid residue known as pitchTar 焦油焦油lGenerally by-product of coke (from coal) productionlWhen coal is heated in coke ovens, it is reduced to coke. The gases (vaporized oils) generated during the process are collected from the oven and refined. The distillation of lighter oils produces tar.l焦油是煤炭在焦化过程中产生的。其产量约占装炉煤的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，在常温常压下其产品呈黑色粘稠液状，密度通常在常在0.95-1.10g/cm3之间，焦油又称煤焦油。之间，焦油又称煤焦油。 Tar pitches 焦油沥青焦油沥青Tar pitches are used for built-up roofing and waterproofing of underground and aboveground constructionlsuch as foundations，retaining walls，dams，and bridgeslAboveground structures experience great fluctuations in environmental conditions，and waterproofing compounds should be able to withstand these changes without becoming brittle or too soft5.1.2 AsphaltsAsphalts 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 temperatureThe natural deposits of asphalts are of two types：Natural rock asphaltslDeposits of sandstone or limestone filled with asphaltsNative asphalts or lake asphaltslLake Trinidad特立尼达岛特立尼达岛，West Indies (a 110-acre lake containing about 40 percent bitumen mixed with water, fine siliceous silt, clay, and organic matter);lBermudez，Venezuela (lake asphalt containing about 65 percent bitumen)Trinidad Lake Asphalt特立尼达岛特立尼达岛 特立尼达和多巴哥特立尼达和多巴哥的主的主岛岛。与。与委内瑞拉委内瑞拉东北部海岸相望，最近东北部海岸相望，最近处仅处仅11公里。面积公里。面积4，828平方公里。人口平方公里。人口101.6万（万（1980）。）。1532年起沦为西班牙殖民地，后被英、荷、法侵占，年起沦为西班牙殖民地，后被英、荷、法侵占，1802年成年成为英国殖民地。为英国殖民地。1962年独立后成为该国领土的主要部分。岛上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（脉的阿里波山（940米）。向南地势降低，大部分地方为不超过米）。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。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，平方公里）及沿海大陆架富藏石油和天然气，西南部有闻名世界西南部有闻名世界的沥青湖的沥青湖。炼油能力超过开采能力，主要炼油中心和石油输出港。炼油能力超过开采能力，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。区主要分布在中部平原，甘蔗为传统经济作物。*5.2 Petroleum asphaltPetroleum asphalts are classified into four types：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphaltsUsages of petroleum asphalts Petroleum asphalts are used in lconstruction of flexible pavementslroof construction (asphalt shingles, rolled roofing, and built-up roofing),lfor insulation (electrical insulation and building paper)lwaterproofing (sprays, paints, and bituminous fabrics) lcanal lining lseal subgrades against the migration of waterlJoint seals*5.2 Petroleum asphaltPetroleum asphalts are classified into four types：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphalts5.2.1 Asphalt CementAsphalt 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 obtained after separation of lubricating oils from crude petroleum. Properties of asphalt cement It possesses excellent binding properties and adheres very well to aggregate particles.lwhen used in pavement construction it is necessary to heat both the asphalt cement and the aggregates prior to mixingsuperior waterproof qualitieslPavement built using paving asphalt is waterproof and resistant to many types of chemical attack.*5.2 Petroleum asphaltPetroleum asphalts are classified into four types：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphalts5.2.2 Cutback Asphalts Two types of asphalt are available in liquid form:lcutback asphalt lemulsified asphaltCutback asphalt- is asphalt cement that is liquefied by blending with petroleum solvents (called diluents). Cutback asphalt are divided into three typesSlow-curingMedium-curingRapid-curing Slow-curing cutback asphaltSlow-curing cutback asphalt is asphalt cement blended with oils of low volatility，such as diesel oil 柴油柴油. Its viscosity value is low and it hardens very slowly.It is used for cold laid pavement bases. Medium-curing cutback asphaltMedium-curing cutback asphalt is obtained by blending asphalt cement with kerosene- 煤油煤油 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 treatmentsRapid-curing cutback asphaltRapid-curing cutback asphalt is asphalt cement blended with naphtha or gasoline- 汽油汽油 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 asphaltPetroleum asphalts are classified into four types：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphalts5.2.3 Emulsified AsphaltEmulsified asphalt is composed of asphalt cement and water that contains a small amount of an emulsifying agentlSoapslwater-soluble chemicalslfine clay乳化沥青乳化沥青 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。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。可以常温使用，且可以和冷的和潮湿的石料一起使用。当乳化沥青当乳化沥青破乳破乳凝固时凝固时- 还原为连续的沥青并且水分还原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。、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。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，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，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。如粘层油、透层油等。*advantages of emulsified asphaltemulsified asphalt can be applied during damp weather and with aggregates that are cold or hotthe quantity of materials applied is controlled automatically lbecause any excess (water) will drain into the subgradesaving energylThe use of emulsified asphalt also eliminates the use of fuel required to heat and dry the aggregates in the asphalt cement mixtureslreduces energy requirements through reduction or elimination of petroleum distillates used in cutback asphalts. *disadvantage of emulsified asphaltpollutionlbecause 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 streams, causing ground contamination.*5.2 Petroleum asphaltPetroleum asphalts are classified into four types：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphalts5.2.4 Blown AsphaltBlown asphalt is obtained by blowing air through the semisolid residue obtained during the later stages of the distillation processProperties lrelatively firm in consistency lDuctilelweather resistant and can withstand temperature changes very wellUsages of Blown asphaltsBlown asphalts use in the manufacturelroofing materialslwaterproof paintsl joint fillers (for concrete pavements)lundersealing old，rigid pavementsl mineral rubber