第8单元翻译
8 Road Engineering Ⅱ:
Road Subgrade and Pavement Engineering
路基路面工程
Pavement Types
道路类型
1 、Introduction
1、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 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” because they are substantially stiffer than flexible pavements due to PCC’s 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 PCC’s high stiffness, tends to distribute the load over a relatively wide area of subgrade (see Figure 8-3). The concrete slab itself supplies most of a rigid pavement’s structural capacity. Flexible pavement uses more flexible surface course and distributes loads over a smaller area. It relies on a combination of layers for transmitting 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) 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 and 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 Pavement
2、柔性路面
Flexible pavements are so 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 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, material 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 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 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 pavement 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 pavement 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 asphalt (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 (OGFC) 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-Graded 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 further 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, asphalt 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 resistance 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 generally 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 durability. 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: Improved 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 into 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), 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 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 ensure 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-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 mixes use only crushed stone (or gravel) and a small percentage of manufactured sands. There are three types of open-graded mixes typically used in the U.S.:
一个开放等级HMA混合物被设计成水渗透(dense-graded和SMA混合通常不透水)。开放等级混合使用只有碎石或砾石和一个一小部分砂生产。有三种类型
的开放等级混合一般在美国使用。
1) Open-graded friction course (OGFC). Typically 15 percent air voids, no minimum air voids specified, lower aggregate standards than PEM. See Figure 8-7.
(1)开放等级摩擦过程(空隙)。典型的含气率15%,没有指定最小孔隙,降低总比PEM标准。参见图8-7。
2) Porous European mixes (PEM). Typically 18 - 22 percent air voids, specified minimum air voids, higher aggregate standards than OGFC and requires the use of asphalt binder modifiers.
(2)多孔欧洲混合(PEM)。通常含气率18 - 22%,指定最小孔隙,总体水平高于大空隙,需要沥青粘结剂修饰符的使用。
3) Asphalt treated permeable bases (ATPB). Less stringent specifications than OGFC or PEM since it is used only under dense-graded HMA, SMA or PCC for drainage.
(3)沥青渗透治疗基地(ATPB)。严格规范低于空隙或PEM因为它使用只有在稠密等级 HMA,SMA或PCC排水。
Purpose: OGFC and PEM - Used as for surface courses only. They reduce tire splash/spray in wet weather and typically result in smoother surfaces than dense-graded HMA. Their high air voids trap road noise and thus reduce tire-road noise by up to 50-percent (10 dB). ATPB - Used as a drainage layer below dense-graded HMA, SMA or PCC.
目的:大空隙和PEM -仅用作表面课程。他们在潮湿的天气减少轮胎飞溅/喷雾,通常导致平滑表面比稠密等级HMA。高含气率陷阱道路噪声,从而降低轮胎噪声50%(10 dB)。ATPB -作为排水层下面稠密等级HMA,SMA或PCC。
Materials: Aggregate (crushed stone or gravel and
manufactured sands), asphalt binder (with modifiers).
材料:骨料(碎石或砾石和砂生产),沥青结合料(修饰符)。
Mix Design: Less structured than for dense-graded or SMA
mixes. Open-graded mix design generally consists of 1) material selection, 2) gradation, 3) compaction and void determination and4) asphalt binder drain-down evaluation.
结构设计:不如开放等级混合或SMA混合结构。开放等级混合设计通常由1)材料选择,2)分级,3)压实,决心和4)沥青粘结剂排干评估。
Other Info: Both OGFC and PEM are more expensive per ton than dense-graded HMA, but the unit weight of the mix when in-place is lower, which partially offsets the higher per-ton cost. The open gradation creates pores in the mix, which are essential to the mix’s proper function. Therefore anything that tends to clog these pores, such as low-speed traffic, excessive dirt on the roadway or deicing sand, should be avoided.
其他信息:每吨大空隙和PEM都更贵比开放等级HMA,但就地时混合的单位重量低,这部分抵消每吨成本就越高。开放等级造成毛孔的混合,混合的本征函数至关重要。因此任何倾向于这些毛孔堵塞,如低速交通,过多的灰尘在巷道或除冰沙,应该避免。
3 Rigid Pavement
3、刚性路面
Rigid pavements are so named because the pavement structure deflects very little under loading due to the high modulus of elasticity of their surface course. A rigid pavement structure is typically composed of a PCC surface course built on top of either the subgrade or an underlying base course. Because of its relative rigidity, the pavement structure distributes loads over a wide area with only one, or at most two, structural layers.
刚性路面被如此命名是因为路面结构偏转很少下 加载,由于其面层的弹性模量高。刚性路面结构为 通常由建立在无论是路基或潜在的顶部表面的PCC当
然 基层。因为它的相对刚性的,路面结构分布荷载在很宽的区域具有唯一的一个,或至多两结构层.
The typical rigid pavement structure consists of:
典型的刚性路面结构包括
Surface course. This is the top layer, which consists of the PCC slab.
面层:这是顶层,它由宝成板坯
Base course. This is the layer directly below the PCC layer and generally consists of aggregate or stabilized subgrade.
基层:这是宝成层正下方的层,一般由骨料或稳定路基
Subbase course. This is the layer (or layers) under the base layer. A subbase is not always needed and therefore may often be omitted.
垫层:这是基体层之下的层(或中间层)。一个底基层并不总是需要的,因此可能经常被省略。
Almost all rigid pavement is made with PCC, thus this Guide only discusses PCC pavement. Rigid pavements are
differentiated into three major categories by their means of crack control:
几乎所有硬质路面是用PCC,因此本指南只讨论PCC路面。 刚性路面分化为三大类由裂缝控制的手段:
Jointed plain concrete pavement (JPCP). This is the most common type of rigid pavement. JPCP controls cracks by
dividing the pavement up into individual slabs separated by contraction joints. Slabs are typically one lane wide and between 3.7 m and 6.1 m long. JPCP does not use any reinforcing steel but does use dowel bars and tie bars.
普通混凝土路面(JPCP)。这是刚性路面的最常见的类型。 中化摩除以路面成由收缩分开个别砖裂缝控制 关节。地砖通常是一个车道宽之间3.7米和6.1
米长。中化摩不使用任何 钢筋,但并使用木钉酒吧和拉杆。
Jointed reinforced concrete pavement (JRCP). As with JPCP, JRCP controls cracks by dividing the pavement up into
individual slabs separated by contraction joints. However, these slabs are much longer (as long as 15 m) than JPCP slabs, so JRCP uses reinforcing steel within each slab to control within-slab cracking. This pavement type is no longer
constructed in the U.S. due to some long-term performance problems. 钢筋混凝土路面:随着钢筋混凝土路面技术的发展,钢筋混凝土路面被分离成单个板控制收缩缝。然而,这些板(长达15米)比钢筋混凝土路面板长,所以钢筋混凝土路面采用每个板内布置钢筋控制板开裂。由于长期的性能问题该路面类型已不在美国使用。
Continuously reinforced concrete pavement (CRCP). This type of rigid pavement uses reinforcing steel rather than contraction joints for crack control. Cracks typically appear ever 1.1 -2.4 m; and are held tightly together by the underlying reinforcing steel.
连续配筋混凝土路面(CRCP)。这种类型的刚性路面的用途 钢筋,而不是收缩缝的裂缝控制。裂缝通常出现过1.1 - 2.4米,以及由基础钢筋举行紧紧地握在一起。
(1) Jointed Plain Concrete Pavement (JPCP)
(1)混凝土路面
Jointed plain concrete pavement (JPCP) uses contraction joints to control cracking and does not use any reinforcing steel. Transverse joint spacing is selected so that
temperature and moisture stresses do not produce intermediate cracking between joints. This typically results in a spacing no longer than about 6.1 m. Dowel bars are typically used at transverse joints to assist in load transfer. Tie bars are
typically used at longitudinal joints. 混凝土路面使用收缩缝控制开裂不使用任何钢筋。横缝间距使混凝土路面在温度和湿度影响下不产生中间裂纹。这通常会在间距不超过6.1米设置木钉协助横缝转移荷载。系杆通常用于在纵向接头。
Crack Control: Contraction joints, both transverse and longitudinal.
裂缝控制:缩缝,横向和纵向的。
Joint Spacing: Typically between 3.7 m and 6.1 m. Due to the nature of concrete, slabs longer than about 6.1 m will usually crack in the middle. Depending upon environment and materials slabs shorter than this may also crack in the middle. 节理间距:通常在3.7米和6.1米。由于混凝土的性质,板超过6.1米,通常会有中间裂纹。这取决于环境和材料板也可能产生中间裂纹。
Reinforcing Steel: None.
钢筋:无。 Load Transfer: Aggregate interlock and dowel bars. For low-volume roads aggregate interlock is often adequate. However, high-volume roads generally require dowel bars in each transverse joint to prevent excessive faulting.
荷载传递:骨料联锁和销钉。低交通量道路骨料联锁通常是足够的。然而,高容量的道路通常需要在每个销钉处设置横缝防止断层。
Other Info: A majority of U.S. State DOTs build JPCP because of its simplicity and proven performance.
其他信息:美国大多数地区建立钢筋混凝土路面实验室研究其性能。
(2) Jointed Reinforced Concrete Pavement (JRCP)
(2)钢筋混凝土路面(JRCP)
Jointed reinforced concrete pavement (JRCP) uses
contraction joints and reinforcing steel to control cracking. Transverse joint spacing is longer than that for JPCP and typically ranges from about 7.6 m to 15.2 m. Temperature and
moisture stresses are expected to cause cracking between joints, hence reinforcing steel or a steel mesh is used to hold these cracks tightly together. Dowel bars are typically used at transverse joints to assist in load transfer while the reinforcing steel/wire mesh assists in load transfer across cracks. 钢筋混凝土路面(JRCP)使用横缝钢筋控制裂缝。横缝间距范围通常从长约
7.6米到15.2米,考虑温度和湿度应力造成接头开裂,因此使用钢筋或钢网把这些裂缝紧密地结合在一起。销钉通常用在横缝协助荷载传递而钢筋线网格协助横跨裂缝的荷载传递。
Crack Control: Contraction joints as well as reinforcing steel.
裂缝的控制:伸缩缝以及钢筋。
Joint Spacing: Longer than JPCP and up to a maximum of about 15 m. Due to the nature of concrete, the longer slabs associated with JRCP will crack.
节理间距:比钢筋混凝土长最多长达15米。由于混凝土的性质,钢筋混凝土长板将产生裂纹。
Reinforcing Steel: A minimal amount is included mid-slab to hold cracks tightly together. This can be in the form of deformed reinforcing bars or a thick wire mesh.
钢筋:布置在板中保持裂缝紧密地结合在一起,也可以放入变形钢筋或粗线网的形式。
Load Transfer: Dowel bars and reinforcing steel. Dowel bars assist in load transfer across transverse joints while
reinforcing steel assists in load transfer across mid-panel cracks.
荷载传递:插筋和钢筋。销钉协助之间的负载转移,钢筋在横缝中帮助裂缝传递荷载。
Other Info: During construction of the interstate system,
most agencies in the Eastern and Midwestern U.S. built JRCP. Today only a handful of agencies employ this design. In general, JRCP has fallen out of favor because of inferior performance when compared to JPCP and CRCP. 其他信息:州际公路系统的建设过程中,在美国东部和大多数中西部建成钢筋混凝土研究机构。今天只有少数机构采用这样的设计。一般来说钢筋混凝土路面已经失宠的原因是钢筋混凝土路面性能比连续钢筋混凝土路面差。
(3) Continuously Reinforced Concrete Pavement (CRCP)
(3)连续配筋混凝土路面(CRCP)
Continuously reinforced concrete pavement (CRCP, see Figure 8-8) does not require any contraction joints.
Transverse cracks are allowed to form but are held tightly together with continuous reinforcing steel. Research has shown that the maximum allowable design crack width is about 0.5 mm to protect against spalling and water penetration. Cracks typically form at intervals of 1.1 - 2.4 m. Reinforcing steel usually constitutes about 0.6 - 0.7 percent of the cross-sectional pavement area and is located near mid-depth in the slab. Typically, No. 5 and No. 6 deformed reinforcing bars are used.
连续配筋混凝土路面(CRCP,如图8-8)不需要任何收缩缝。连续钢筋允许横向裂纹形成却紧紧地在一起。研究表明,设计最大允许裂缝宽度约0.5毫米用于抗剥落、渗水。裂缝通常形式间隔1.1~2.4μm。钢筋通常构成约0.6%~0.7%。通常情况下,横断面路面使用5号和6号变形钢筋做成骨架。
During the 1970’s and early 1980’s, CRCP design thickness was typically about 80 percent of the thickness of JPCP. However, a substantial number of these thinner pavements developed distress sooner than anticipated and as a
consequence, the current trend is to make CRCP the same thickness as JPCP. The reinforcing steel is assumed to only
handle nonload-related stresses and any structural contribution to resisting loads is ignored.
在1970年到1980年代初,连续配筋混凝土路面设计厚度通常约钢筋混凝土路面的80%。然而,大量的这些较薄的路面使用效果并不好,因此,目前的趋势是使连续配筋混凝土路面与钢筋混凝土路面厚度相同。钢筋被认为只承受压力而对结构的抗负载作用被忽略。
Crack Control: Reinforcing steel.
裂缝的控制:钢筋。
Joint Spacing: Not applicable. No transverse contraction joints are used.
节理间距:不适用。没有使用横向缩缝。
Reinforcing Steel: Typically about 0.6 - 0.7 percent by cross-sectional area.
钢筋:通常约为0.6%~0.7%的横截面面积。
Load Transfer: Reinforcing steel, typically No. 5 or 6 bars, grade 60.
荷载传递:钢筋,通常是5号或6号60级配的。
Other Info: CRCP generally costs more than JPCP or JRCP initially due to increased quantities of steel. Further, it is generally less forgiving of construction errors and provides fewer and more difficult rehabilitation options. However, CRCP may demonstrate superior long-term performance and cost-effectiveness. Some agencies choose to use CRCP designs in their heavy urban traffic corridors.
其他信息:连续配筋混凝土路面由于使用更多钢材成本一般比钢筋混凝土路面和混凝土路面高。此外,连续配筋混凝土路面施工更困难。然而,可能会表现出长期性能和成本效益。一些机构选择大量使用连续配筋混凝土路面设计城市交通走廊。