第8单元翻译.docx

1、第8单元翻译8 Road Engineering : Road Subgrade and Pavement Engineering路基路面工程Pavement Types道路类型1 、Introduction1、前言Hard surfaced pavements, which make up about 60 percent of U.S. roads and 70 percent of Washington State roads are typically categorized into flexible and rigid pavements:占美国60%和占华盛顿70%的公路的坚硬路

2、面都可以划分为柔性路面和刚性路面。Flexible pavements are those which are surfaced with bituminous (or asphalt) materials (see Figure 8-1). These types of pavements are called “flexible” since the total pavement structure “bends” or “deflects” due to traffic loads. A flexible pavement structure is generally composed

3、of several layers of materials which can accommodate this “flexing”.柔性路面的表层都是沥青类材料（见图8-1），由于在交通荷载的情况下，这种路面结构会发生弯曲并有弯沉出现，所以，这种路面叫做“柔性路面”。柔性路面通常是由几层柔性良好的材料组成的。Rigid pavements are those which are surfaced with portland cement concrete (PCC) (see Figure 8-2). These types of pavements are called “rigid”

4、because they are substantially stiffer than flexible pavements due to PCCs high stiffness.刚性路面的表层是水泥混凝土（见图8-2），因为水泥混凝土刚度较大，它们比柔性路面更加坚硬，所以，这种路面叫做“刚性路面”。Each of these pavement types distributes load over the subgrade in a different fashion. Rigid pavement, because of PCCs high stiffness, tends to dist

5、ribute the load over a relatively wide area of subgrade (see Figure 8-3). The concrete slab itself supplies most of a rigid pavements structural capacity. Flexible pavement uses more flexible surface course and distributes loads over a smaller area. It relies on a combination of layers for transmitt

6、ing load to the subgrade (see Figure 8-4).这两种路面类型通过不同的方式把荷载传到路基上。对于刚性路面，因为他的刚度比较大，所以，它更趋向把荷载分布到一个更大的区域传到地基上（见图8-3），而水泥混凝土则提供了大部分的结构承载力。然而，柔性路面则通过柔性面层把荷载分布到一个较小区域，它主要依靠路面结构各个层次的组合把荷载传递到路基上（见图8-4）。In general, both flexible and rigid pavements can be designed for long life (e.g., in excess of 30 years)

7、 with only minimal maintenance. Both types have been used for just about every classification of road. Certainly there are many different reasons for choosing one type of pavement or the other, some practical, some economical, and some political. As a point of fact, 93 percent of U.S. paved roads an

8、d about 87 percent of Washington State paved roads are surfaced with bituminous (asphalt) materials.一般来说，不管是刚性路面还是柔性路面，在很少维修的情况下，可以达到其设计寿命（超过30年）。这两种路面类型都可以被用到各种道路工程中，当然，人们在选择使用这一种道路类型还是另一种时，考虑更多的是这条道路的实用性、经济性和政治性。然而，事实上，美国93%的公路和华盛顿87%的公路都是选用的沥青柔性路面。2 Flexible Pavement2、柔性路面Flexible pavements are s

9、o named because the total pavement structure deflects, or flexes,under loading. A flexible pavement structure is typically composed of several layers of materials. Each layer receives the loads from the above layer, spreads them out, and then passes on these loads to the next layer below. Thus, the

10、further down in the pavement structure a particular layer is, the less load (in terms of force per area) it must carry.因为在荷载作用下，路面会发生弯曲变形，柔性路面的名称由此而来。一个典型的柔性路面结构是由几层不同的路面材料组成的。路面结构中的每一层都受到上面一层传来的荷载，然后将其分布，并将它传给他下面的这一层，由此，在路面结构中，越深的地方，所收到的力越小。In order to take maximum advantage of this property, mater

11、ial layers are usually arranged in order of descending load bearing capacity with the highest load bearing capacity material (and most expensive) on the top and the lowest load bearing capacity material (and least expensive) on the bottom. The typical flexible pavement structure consists of:为了更好地发挥这

12、种性能优势，工程师通常按承载能力从上到下逐渐降低的顺序来安排结构层布置，把承载能力好的材料安排在路面结构的上面，而把承载力差的材料安排在路面结构的下面。路面结构包括：Surface course. This is the top layer and the layer that comes in contact with traffic. It maybe composed of one or several different HMA sublayers.面层：面层是道路最上面的一层，它与各种道路交通相接触。它可能包括一层或者几层不同的热拌沥青混合料。Base course. This is

13、 the layer directly below the HMA layer and generally consists of aggregate (either stabilized or unstabilized).基层：基层位于热拌沥青混合料面层以下，它通常由各种集料（包括稳定集料和不稳定集料）组成。Subbase course. This is the layer (or layers) under the base layer. A subbase is not always needed.垫层：垫层在基层下面，垫层有时候并不存在。There are many different

14、 types of flexible pavements. This section covers three of the more common types of HMA mix types used in the U.S. HMA mix types differ from each other mainly in maximum aggregate size, aggregate gradation and asphalt binder content/type. This Guide focuses on dense-graded HMA in most flexible pavem

15、ent sections because it is the most common HMA pavement material in the U.S. This section provides a brief exposure to: 在工程中，有许多不同类型的柔性面层。在美国，有三种很常见的热拌沥青混合料混合类型。由于集料最大粒径、集料级配和沥青混合料类型的不同，热拌沥青混合料的混合类型有所不同。这篇文章主要介绍了在柔性路面中常用的密集配热拌沥青混合料，因为他是美国最常见的热拌沥青混合料路面材料。下面这一部分提供了一个简短陈述：Dense-graded HMA. Flexible pav

16、ement information in this Guide is generally concerned with dense-graded HMA. Dense-graded HMA is a versatile, all-around mix making it the most common and well-understood mix type in the U.S.密集配热拌沥青混合料：这篇文章中的柔性路面数据基本上都与密集配热拌沥青混合料有关。密集配热拌沥青混合料是一种通用的综合的混合料，它的使用让它成为美国最受欢迎的热拌沥青混合料类型。Stone matrix asphal

17、t (SMA). SMA, although relatively new in the U.S., has been used in Europe as a surface course for years to support heavy traffic loads and resist studded tire wear.沥青玛蹄脂碎石：沥青玛蹄脂碎石在美国出现还没多少年，但是，它在欧洲却使用了好多年了，被用来支持重型交通荷载并且用来抵抗轮胎磨损带来的变形。Open-graded HMA. This includes both open-graded friction course (O

18、GFC) and asphalt treated permeable materials (ATPM). Open-graded mixes are typically used as wearing courses (OGFC) or underlying drainage layers (ATPM) because of the special advantages offered by their porosity.开级配热拌沥青混合料：开级配热拌沥青混合料包括开级配沥青磨耗层和沥青处治排水性材料。开级配沥青混合料由于孔隙率的特殊性质而被用在磨耗层或者是排水层以下。(1) Dense-G

19、raded Mixes（1） 密级配热拌沥青混合料A dense-graded mix (see Figure 8-5) is a well-graded HMA mixture intended for general use. When properly designed and constructed, a dense-graded mix is relatively impermeable. Dense-graded mixes are generally referred to by their nominal maximum aggregate size. They can fur

20、ther be classified as either fine-graded or coarse-graded. Fine-graded mixes have more fine and sand sized particles than coarse-graded mixes (see Table 8-1 for definitions of fine- andcoarse-graded mixes).平常使用的密级配混合料是一种级配良好的热拌沥青混合料。当通过适当地设计和施工，它的渗透性会很差，密级配混合料更多地是通过它的公称最大集料粒径被认出，它们可以更加细分为细粒式和粗粒式。和粗粒

21、式相比细粒式有更多优良的和像沙子一样的集料（见表8-1，细粒式和粗粒式的定义）Purpose: Dense-graded mixes are suitable for all pavement layers and for all traffic conditions. They work well for structural, friction, leveling and patching needs.目的：密级配混合料适用于所有的路面层次和所有的路面条件，在路面结构道路磨损、道路平整和道路维修上，它都表现的很好。Materials: Well-graded aggregate, asph

22、alt binder (with or without modifiers), RAP.材料：级配良好的集料、沥青混合料、再生沥青路面材料Mix Design: Superpave, Marshall or Hveem procedures.配合比设计：高性能沥青路面设计，马歇尔及海姆配合比设计Other Info: Particulars about dense-graded HMA are covered by flexible pavement sections in the rest of this Guide.其他信息：密级配热拌沥青混合料的更多细节存在于这篇文章下面关于柔性路面的部

23、分。(2) Stone Matrix Asphalt (SMA) Mixes（2）石基质沥青(SMA)混合Stone matrix asphalt (SMA) is a gap-graded HMA that is designed to maximize deformation (rutting) resistance and durability by using a structural basis of stone-on-stone contact (see Figure 8-6). Because the aggregates are all in contact, rut resi

24、stance relies on aggregate properties rather than asphalt binder properties.石基质沥青(SMA)是一种盖普等级HMA设计最大化变形(发情)电阻和耐用性通过使用基础结构石石联系(见图8-6)。因为总量都在接触,常规电阻依赖于总体性能而不是沥青粘结剂性能。Since aggregates do not deform as much as asphalt binder under load, this stone-on-stone contact greatly reduces rutting. SMA is general

25、ly more expensive than a typical dense-graded HMA (about 20% 25%) because it requires more durable aggregates, higher asphalt content and, typically, a modified asphalt binder and fibers. In the right situations it should be cost-effective because of its increased rut resistance and improved durabil

26、ity. SMA, originally developed in Europe to resist rutting and studded tire wear, has been used in the U.S. since about 1990.由于骨料不变形载荷沥青粘结剂,这石头与石头的接触大大减少车辙。SMA通常更昂贵比典型稠密等级HMA(约20% 25%),因为它需要更多的持久的骨料,沥青含量高,一般情况下,改性沥青粘结剂和纤维。在合适的情况下应该是划算的,因为它增加了抗车辙和提高耐久性。SMA,最初在欧洲抵抗车辙和镶嵌轮胎磨损,1990年已在美国使用。Purpose: Improv

27、ed rut resistance and durability. Therefore, SMA is almost exclusively used for surface courses on high volume interstates and U.S. Roads.目的:改进的常规电阻和耐久性。因此,SMA几乎完全用于表面课程高容量和美国州际高速公路。Materials: Gap-graded aggregate (usually from coarse aggregate, manufactured sands and mineral filler all combined int

28、o a final gradation), asphalt binder (typically with a modifier).材料:盖普等级聚合(通常从粗集料,生产砂和矿物填料组合成一个最终层次)沥青结合料与一个修饰词(通常)。Mix Design: Superpave or Marshall procedures with modifications.混合料配合比设计:高性能沥青路面或马歇尔和修改程序。Other Info: Because SMA mixes have a high asphalt binder content (on the order of 6 percent),

29、as the mix sits in the HMA storage silos, transport trucks, and after it is placed, the asphalt binder has a tendency to drain off the aggregate and down to the bottom - a phenomenon known as “mix draindown”. Mix draindown is usually combated by adding cellulose or mineral fibers to keep the asphalt

30、 binder in place. Cellulose fibers are typically shredded newspapers and magazines, while mineral fibers are spun from molten rock. A laboratory test is run during mix design to ensure the mix is not subject to excessive draindown. In mix design a test for voids in the coarse aggregate is used to en

31、sure there is stone-on-stone contact. Other reported SMA benefits include wet weather friction (due to a coarser surface texture), lower tire noise (due to a coarser surface texture) and less severe reflective cracking. Mineral fillers and additives are usually added to minimize asphalt binder drain

32、-down during construction, increase the amount of asphalt binder used in the mix and to improve mix durability.其他信息:因为SMA混合沥青粘结剂含量高(6百分比的顺序),混合坐在HMA存储筒仓,运输卡车,放置后,沥青结合料往往会流失掉的聚合和底部这种现象被称为“混合排干”。混合排干通常是打击通过添加纤维素或矿物纤维沥青粘结剂在的地方。纤维素纤维通常是碎报纸和杂志,而从熔融岩石矿物纤维纺。实验室测试是运行在混合设计,确保不受过度排干混合。在混合设计一个测试粗骨料的孔隙是用于确定石石接触。其他报道SMA的好处包括潮湿天气摩擦(由于粗表面纹理),降低轮胎噪声(由于粗表面纹理)和不太严重的反射裂缝。矿物填料和添加剂通常添加到减少沥青粘结剂排干施工,增加沥青粘结剂用于混合和提高耐久性。(3) Open-Graded Mixes（3）开放等级混合An open-graded HMA mixture is designed to be water permeable (dense-graded and SMA mixes usually are not permeable). Open-graded m