土木工程材料第五章1.ppt

Ch5 Bituminous Materials•5.1 Types of asphalt•5.2 Petroleum asphalt•5.3 Properties of asphalt•5.4 Asphalt grades•5.5 Spray applications•5.6 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 complex hydrocarbons ( 烃, 碳氢化合物).•Features of bitumenlCompletely soluble in carbon disulfide (CS2)lNonvolatilelSoften when heated沥青分类•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；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 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 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在240℃~330℃之 间，燃点比闪点约高3℃~6℃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 constructionlability to adhere to solid particles limpermeability or water resistance•Uses 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 structures．5.1.1 Tars and pitches•Tars, 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 is tar．Further processing yields a solid or semisolid residue known as pitch．•Tar 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 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 waterproofing of underground and aboveground constructionlsuch as foundations，retaining walls，dams，and bridges．lAboveground 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 Asphalts•Asphalts are cementitious materials in which the predominant constituent materials are bitumens.•Natural deposits or petroleum asphalt•The consistency of asphalts varies widely from solid to semisolid at normal temperature ．The natural deposits of asphalts are of two types：•Natural rock asphaltslDeposits of sandstone or limestone filled with asphalts•Native asphalts or lake asphaltslLake 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);lBermudez，Venezuela (lake asphalt containing about 65 percent bitumen)Trinidad 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：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 asphalt•Petroleum asphalts are classified into four types：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphalts5.2.1 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 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 mixing．•superior waterproof qualitieslPavement 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：lAsphalt cementslCutback asphaltslEmulsified asphaltslAir-blown asphalts5.2.2 Cutback Asphalts• Two types of asphalt are available in liquid form:lcutback asphalt lemulsified asphalt•Cutback asphalt---- is asphalt cement that is liquefied by blending with petroleum solvents (called diluents). Cutback asphalt are divided into three types•Slow-curing•Medium-curing•Rapid-curing Slow-curing cutback asphalt•Slow-curing cutback asphalt is aspha。