《土木工程材料第五章1.ppt》由会员分享，可在线阅读，更多相关《土木工程材料第五章1.ppt（34页珍藏版）》请在三一文库上搜索。
1、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
2、of complex hydrocarbons (烃, 碳氢化合物). Features of bitumen Completely soluble in carbon disulfide (CS2) Nonvolatile Soften 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
3、属衍生物组成的混合物。通常沥青闪点在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 construction ability to adhere to solid particles impermeability or wat
4、er resistance Uses of bituminous materials roadways pavements many construction products such 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,
5、 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 tarFurther processing yields a solid or semisolid residue known as pitch,Tar 焦油 Generally by-product of coke (from coal) production Whe
6、n 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. 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 pit
7、ches are used for built-up roofing and waterproofing of underground and aboveground construction such as foundations，retaining walls，dams，and bridges Aboveground structures experience great fluctuations in environmental conditions，and waterproofing compounds should be able to withstand these changes
8、 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
9、asphalts are of two types：,Natural rock asphalts Deposits of sandstone or limestone filled with asphalts Native asphalts or lake asphalts Lake 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，Ven
10、ezuela (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
11、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： Asphalt cements Cutback asphalts Emulsified asphalts Air-blown asphalts,Usages of petroleum asphal
12、ts,Petroleum asphalts are used in construction of flexible pavements roof 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 mi
13、gration of water Joint seals,*5.2 Petroleum asphalt,Petroleum asphalts are classified into four types： Asphalt cements Cutback asphalts Emulsified asphalts Air-blown asphalts,5.2.1 Asphalt Cement,Asphalt cement is very sticky and highly viscous, especially prepared with the quality and consistency r
14、equired 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. when used in pavement construction it is
15、 necessary to heat both the asphalt cement and the aggregates prior to mixing superior waterproof qualities Pavement 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 cements Cutb
16、ack asphalts Emulsified asphalts Air-blown asphalts,5.2.2 Cutback Asphalts,Two types of asphalt are available in liquid form: cutback asphalt emulsified asphalt Cutback asphalt- is asphalt cement that is liquefied by blending with petroleum solvents (called diluents).,Cutback asphalt are divided int
17、o three types,Slow-curing Medium-curing Rapid-curing,Slow-curing cutback asphalt,Slow-curing cutback 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 cutb
18、ack asphalt,Medium-curing cutback asphalt is obtained by blending asphalt cement with kerosene- 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 treatmen
19、ts,Rapid-curing cutback asphalt,Rapid-curing cutback asphalt is asphalt cement blended with naphtha or 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
20、,Petroleum asphalts are classified into four types： Asphalt cements Cutback asphalts Emulsified asphalts Air-blown asphalts,5.2.3 Emulsified Asphalt,Emulsified asphalt is composed of asphalt cement and water that contains a small amount of an emulsifying agent Soaps water-soluble chemicals fine clay
21、,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
22、 of emulsified asphalt,emulsified asphalt can be applied during damp weather and with aggregates that are cold or hot the quantity of materials applied is controlled automatically because any excess (water) will drain into the subgrade saving energy The use of emulsified asphalt also eliminates the
23、use of fuel required to heat and dry the aggregates in the asphalt cement mixtures reduces energy requirements through reduction or elimination of petroleum distillates used in cutback asphalts.,*disadvantage of emulsified asphalt,pollution because the asphalt is suspended in water, it is susceptibl
24、e 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 asphalt,Petroleum asphalts are classified into four types： Asphalt cements Cutback asphalts Emulsified asphalts Air-blown asph
25、alts,5.2.4 Blown Asphalt,Blown asphalt is obtained by blowing air through the semisolid residue obtained during the later stages of the distillation process Properties relatively firm in consistency Ductile weather resistant and can withstand temperature changes very well,Usages of Blown asphalts,Blown asphalts use in the manufacture roofing materials waterproof paints joint fillers (for concrete pavements) undersealing old，rigid pavements mineral rubber,