26
1Pavements serve structural, functional and safety purposes. They are necessary not only for roadways but also for parking lots, airports (i. e. , runways/跑道, taxiways/滑行道, aprons and service roads ), industrial sites, ports and so forth.
路面有结构、功能以及安全方面的作用。它们不仅对于车行道是必须的，而且对于停车场，机场，工业场所，港口等也是必须的。 (or subgrade) on which the pavement system is constructed.
路面的结构特性旨在分散车轮下的荷载更大的面积上，来防止应力超过路面系统建于其上的原位土（或路基）的承载能力。 spread over large areas.
在路面和车轮结合面上的荷载施加于相当小的面积上，在作用点上引起很高的应力，但当荷载被分散到大面积上，此应力会随深度降低。
2The functional performance of pavement is related to the users’ requirement for smooth and comfortable riding conditions.
路面的功能主要是与用户对平稳和舒适的乘行条件有关。
. The quality of riding comfort is typically measured by the Present Serviceability Index (PSI), 行车舒适的质量可由美国国有公路及运输协会发展的现有路况性能指标来评价。
The PSI is based primarily on measurements of pavement roughness.
PSI 主要基于路面的粗糙度来衡量。
This is accomplished by a variety of available equipment that essentially measure the condition of the pavement along the traveled way.
许多设备可用来沿着行车道测量路面的条件，由此得到PSI
The PSI deteriorates [di'tiəri əreit] with usage and pavement age and is one of several criteria
[krai'tiəri ə] employed to aid decisions relating to maintenance, rehabilitation, or reconstruction of the pavement.
PSI 随着使用和路面年龄退化，它是有助于决定道路维护、维修、重建的标准之一。
Typical symptoms of pavement distresses are longitudinal and transverse cracking, breaking, swelling and heaving. They affect the structural integrity of a pavement and the level of service to the users.
路面出现问题的典型症状有纵向和横向的断裂、破裂肿胀以及隆起等。它们影响路面的整体性以及对用户的使用性能。
3The safety performance of pavements is mainly related to the skid resistance developed at the pavement tire/轮胎 interface.
路面的安全性能主要与轮胎和路面之间的界面上的抗滑性能有关
This friction or skid resistance can be enhanced by the choice of materials and the various treatments, such as texturing the pavement surface.
这种摩擦或者抗滑性可通过选择材料和诸多处理措施，譬如使路面具有某种纹理结构等来加强。
Another characteristic that is related to safety is the light reflectance of the pavement surface. 另外一个与安全相关的特性是路面的光折射系数。
通过重复使用获得当地土体的多年压缩是路面维护的常用方式
Some exceptions were the heavy stone roadways constructed by some advanced ancient civilizations, including the Romans
也有特例，譬如古代文明修建的重型石路，其中包括现存的罗马人修建的亚壁古道等。 whose famous Appian Way is extant to the present day. Any attempt to replicate the works of these ancient societies given today's material and labor costs would be prohibitively expensive. 在当前给定的材料和人力情况下，任何想再现这些作品的想法都是非常昂贵的。
A derivative of this method of road building, known as the French method, and the practice of overlaying a prepared roadbed with natural or artificial stones (e. g., cobblestones ) continued until fairly recently.
从这种方法衍生出来的FRENCH 法以及在路面上铺一些天然或者人造的石头（譬如鹅卵石）等这种技术一直使用至今。
Other roadbed treatments include artificial compaction and stabilization of unpaved roads, which are typically found in rural areas, on farms, and at construction sites. There are also another two types of pavements:
其它的路基处理措施包括未铺装道路的人工压实和稳定，这些措施常见于农村地区的农田和工地。还有另外两种路面形式：
the asphalt pavements and the Portland-cement concrete pavements . The last two are the most common types of pavements in use today.
沥青路面和混凝土路面，这后两种是当今最常见的路面形式。
5The Asphalt Institute（美国沥青协会）describes asphalt as a “strong cement , readily adhesive, highly waterproof and durable.
美国沥青协会对沥青作了如下解释
它是一种强力结合剂，易粘结，高防水性和耐久性。它是一种塑性物质，能给予混合物可控制的弹性，这个混合物通常结合矿物质骨料形成。
Although a solid or semisolid at ordinary atmospheric temperatures, asphalt may be readily liquefied by the application of heat."
尽管在常温下其处于固态与半固态，沥青可很容易通过热处理液化。”
6The combination of asphalt with graded mineral aggregates is known as asphalt concrete. 沥青与级配的矿物质骨料的混合就是沥青混凝土。
It is in this manner that asphalt is usually applied to pavement design.
沥青也就是以这种方式用于路面设计。 mineral aggregates such as open-graded, coarse-graded or fine-graded.
沥青混凝土混合料有时按照矿质骨料成分的级配和填充料分为开级配沥青混合料、粗级配沥青混合料和细级配沥青混合料。
Open-graded aggregates contain little mineral filler material, and consequently it is characterized by relatively large void areas between aggregate particles in a compacted mix.
开级配骨料包含少量矿物质填充料，因此在其骨料颗粒之间具有相对大的空隙。
Coarse-graded aggregates exhibit a continuous grading of sizes but show a predominance of coarse sizes, whereas fine-graded aggregates have a predominance of fine sizes.
粗级配骨料呈现出尺寸上的连续级配，但主要是粗糙尺寸，然而细级配骨料中细尺寸占主要
A coarse aggregate of uniform size, known as a macadam aggregate, received its name from the Scottish engineer John MacAdam, who first used it in an asphalt mix.
相同尺寸的粗级配骨料称之为碎石骨料，由于苏格兰工程师John MacAdam首次在沥青混合料中使用得名。
7When the asphalt concrete is placed, spread and compacted at atmospheric [,ætməs'ferikl] temperature, it is referred to as a cold-laid mixture, in contrast to hot-laid mixtures, which involve elevated temperatures.
当沥青混合料在常温下摊铺和压实时，就被称作冷拌沥青混合料，它和需加热铺筑的热拌沥青混合料不同。 材料特性和比例以及拌制与铺筑条件的结合能使得沥青混凝土按照稳定性、耐久性和弹性呈现不同的特性，以适应各种各样的使用要求。
8It is worth to note that natural deposits of asphalt exist.
值得指出是：在自然界存在着天然沥青矿。
For example, skeletons of prehistoric animals have been preserved in such deposits at the La Brea pit near Los Angeles, CA.
例如，在加利福尼亚州洛杉矶附近的拉布雷亚沉积坑内发现了一些史前动物的骨骼。
Asphalt material was used in Mesopotamia for roadway construction and waterproofing purposes. 在美索不达米亚，沥青材料用于路面施工以及防水目的。
According to the Asphalt Institute, imported rock asphalt was used in Philadelphia, PA in 1838, and the first asphalt pavement was built in Newark, NJ in 1870.
从沥青协会获知，1838年在费城使用过岩石沥青；第一个沥青路面在纽瓦克修建。
Today asphalt is recovered from petroleum in the process of separation/离析 and refinement of constituents
现在的沥青是从石油离析以及提炼得来的。
9Portland cement is mainly a calcium aluminum silicate that is produced by fusing limestone and clay in a rotary kiln to form a clinker material, which is then grind/ground into a fine powder.
波特兰水泥主要是钙—铝—硅酸盐等，它们是在回转炉里融化石灰石和粘土形成渣块材料时生成的，然后又被碾碎成粉末。
First used by an Englishman, Joseph Aspdin, who patented the substance in 1824
英国人Joseph Aspdin首先使用，并于1824年申请专利。
Portland cement derives its name from its ability to react with water and, through hydration/水合作用, to produce an artificial stone that resembles the limestone/石灰石 deposits found on the
波特兰水泥，其名源于与水相互作用和水合作用的能力产生类似在英格兰波特兰岛上发现的石灰石沉积物这种人工石；
It is a " nonbituminous " cement and is classified as a "hydraulic" cement because it solidifies 它是不含沥青的水泥，称之为水力水泥，因为它遇水就凝固。
In various combinations with water, graded mineral aggregates and other admixtures, Portland cement is used to produce numerous construction materials, such as grout, plaster, mortar and Portland cement concrete.
通过调整水、级配矿物骨料以及其他混合物的组成，波特兰水泥可以生产出许多建筑材料，譬如水泥浆、灰泥、砂浆以及混凝土。
By controlling the combinations of the constituents of the mix, a wide variety of desirable characteristics (e. g., strength, durability and workability) can be
obtained to suit particular applications.
通过控制混合物成分的组合，可以得到一系列想要的特性（诸如强度、耐久性、可使用性）来适应特殊的需要。
The most notable characteristic of Portland cement concrete is its compressive strength. It far exceeds its tensile strength, which is only about 10% of its compressive strength.
波特兰水泥混凝土最显著的特点就是它的抗压强度。抗压强度远大于其抗拉强度。抗拉强度只有抗压强度的10%左右；
For this reason Portland-cement concrete pavements are typically designed to resist compressive forces only. The first reported use of Portland-cement concrete for pavement construction in the United States occurred in 1891 in Bellefontaine, OH俄亥俄州.
基于这个原因，波特兰水泥混凝土常设计仅用于抵抗压力；在美国，波特兰水泥混凝土首次用于路面出现在1891年。
10In case prominent tensile forces are present under particularly heavy loads continuous reinforcement with steel bars is applied to withstand the applied tension.
在拉力突出的重型道路上，连续配筋被用来抵抗拉力
Also, prestressing the structural element is another way for taking full advantage （充分利用）of the compressive strength.
此外，对结构单元施加预加力是充分利用抗压强度的另一种方式。
This involves the application, via tendons embedded in the concrete, of a compressive load on the structure prior to applying the service loads.
这包括在承受使用荷载之前，混凝土中植入钢筋束在结构上产生压力荷载
预压应力可抵消荷载产生的拉应力，如此一来，混凝土仍保持受压状态。
Continuously reinforced or prestressed concrete pavements are commonly used for airport runways and aprons.
连续钢筋或者预应力混凝土通常用于机场的跑道和停机坪
11A fundamental difference between asphalt and Portland-cement concrete pavements lies in the fact that the former is characterized by flexibility, whereas the latter provides rigidity.
沥青混凝土和水泥混凝土之间最根本的区别在于，前者主要是以柔性为特点，而后者主要是刚性的
For this reason the two types of pavement are classified, respectively, as flexible and rigid pavements . The following are the corresponding AASHTO definitions.
基于此原因，主要有两类路面，分别是柔性和刚性路面。美国国有公路运输协会的定义如下。 Flexible pavement. A pavement structure which maintains intimate contact with and distributes loads to the subgrade and depends on aggregate interlock, particle friction and cohesion for stability.
柔性路面：是指与路基结合紧密并传递荷载到路基，并且依靠骨料之间的连锁、粒子之间的摩擦和粘结来维持稳定的一种路面结构。
Rigid pavement. A pavement structure which distributes loads to the subgrade, having as one course a Portland-cement concrete slab of relatively high bending resistance.
刚性路面：传递荷载到路基的一种路面结构，并且具有相对较高的抗弯能力。
根据配筋的方法，刚性路面可分为设置或未设置传力杆的素混凝土（无配筋的）路面、传统的加筋水泥混凝土路面、连续配筋水泥混凝土路面和预应力钢筋混凝土路面。
Dowels are steel rods that connect individual pavement slabs to facilitate the transfer of loads between them.
传力杆是一些连接单独混凝土路面板使之联合受力的钢杆。
In the case of continuously reinforced Portland-cement concrete pavements the reinforcing steel serves this function
对于波特兰水泥混凝土路面来说，加筋即可起到这个作用。
在沥青路面上加铺一层波特兰水泥混凝土路面板的复合路面很常见
Moreover, a recent practice of overlaying a Portland-cement concrete layer on old asphalt pavements, called "whitetopping" appears to be gaining in popularity
另外，最近一项称之为白色罩面的路面翻新技术开始变得流行起来。
26
1Pavements serve structural, functional and safety purposes. They are necessary not only for roadways but also for parking lots, airports (i. e. , runways/跑道, taxiways/滑行道, aprons and service roads ), industrial sites, ports and so forth.
路面有结构、功能以及安全方面的作用。它们不仅对于车行道是必须的，而且对于停车场，机场，工业场所，港口等也是必须的。 (or subgrade) on which the pavement system is constructed.
路面的结构特性旨在分散车轮下的荷载更大的面积上，来防止应力超过路面系统建于其上的原位土（或路基）的承载能力。 spread over large areas.
在路面和车轮结合面上的荷载施加于相当小的面积上，在作用点上引起很高的应力，但当荷载被分散到大面积上，此应力会随深度降低。
2The functional performance of pavement is related to the users’ requirement for smooth and comfortable riding conditions.
路面的功能主要是与用户对平稳和舒适的乘行条件有关。
. The quality of riding comfort is typically measured by the Present Serviceability Index (PSI), 行车舒适的质量可由美国国有公路及运输协会发展的现有路况性能指标来评价。
The PSI is based primarily on measurements of pavement roughness.
PSI 主要基于路面的粗糙度来衡量。
This is accomplished by a variety of available equipment that essentially measure the condition of the pavement along the traveled way.
许多设备可用来沿着行车道测量路面的条件，由此得到PSI
The PSI deteriorates [di'tiəri əreit] with usage and pavement age and is one of several criteria
[krai'tiəri ə] employed to aid decisions relating to maintenance, rehabilitation, or reconstruction of the pavement.
PSI 随着使用和路面年龄退化，它是有助于决定道路维护、维修、重建的标准之一。
Typical symptoms of pavement distresses are longitudinal and transverse cracking, breaking, swelling and heaving. They affect the structural integrity of a pavement and the level of service to the users.
路面出现问题的典型症状有纵向和横向的断裂、破裂肿胀以及隆起等。它们影响路面的整体性以及对用户的使用性能。
3The safety performance of pavements is mainly related to the skid resistance developed at the pavement tire/轮胎 interface.
路面的安全性能主要与轮胎和路面之间的界面上的抗滑性能有关
This friction or skid resistance can be enhanced by the choice of materials and the various treatments, such as texturing the pavement surface.
这种摩擦或者抗滑性可通过选择材料和诸多处理措施，譬如使路面具有某种纹理结构等来加强。
Another characteristic that is related to safety is the light reflectance of the pavement surface. 另外一个与安全相关的特性是路面的光折射系数。
通过重复使用获得当地土体的多年压缩是路面维护的常用方式
Some exceptions were the heavy stone roadways constructed by some advanced ancient civilizations, including the Romans
也有特例，譬如古代文明修建的重型石路，其中包括现存的罗马人修建的亚壁古道等。 whose famous Appian Way is extant to the present day. Any attempt to replicate the works of these ancient societies given today's material and labor costs would be prohibitively expensive. 在当前给定的材料和人力情况下，任何想再现这些作品的想法都是非常昂贵的。
A derivative of this method of road building, known as the French method, and the practice of overlaying a prepared roadbed with natural or artificial stones (e. g., cobblestones ) continued until fairly recently.
从这种方法衍生出来的FRENCH 法以及在路面上铺一些天然或者人造的石头（譬如鹅卵石）等这种技术一直使用至今。
Other roadbed treatments include artificial compaction and stabilization of unpaved roads, which are typically found in rural areas, on farms, and at construction sites. There are also another two types of pavements:
其它的路基处理措施包括未铺装道路的人工压实和稳定，这些措施常见于农村地区的农田和工地。还有另外两种路面形式：
the asphalt pavements and the Portland-cement concrete pavements . The last two are the most common types of pavements in use today.
沥青路面和混凝土路面，这后两种是当今最常见的路面形式。
5The Asphalt Institute（美国沥青协会）describes asphalt as a “strong cement , readily adhesive, highly waterproof and durable.
美国沥青协会对沥青作了如下解释
它是一种强力结合剂，易粘结，高防水性和耐久性。它是一种塑性物质，能给予混合物可控制的弹性，这个混合物通常结合矿物质骨料形成。
Although a solid or semisolid at ordinary atmospheric temperatures, asphalt may be readily liquefied by the application of heat."
尽管在常温下其处于固态与半固态，沥青可很容易通过热处理液化。”
6The combination of asphalt with graded mineral aggregates is known as asphalt concrete. 沥青与级配的矿物质骨料的混合就是沥青混凝土。
It is in this manner that asphalt is usually applied to pavement design.
沥青也就是以这种方式用于路面设计。 mineral aggregates such as open-graded, coarse-graded or fine-graded.
沥青混凝土混合料有时按照矿质骨料成分的级配和填充料分为开级配沥青混合料、粗级配沥青混合料和细级配沥青混合料。
Open-graded aggregates contain little mineral filler material, and consequently it is characterized by relatively large void areas between aggregate particles in a compacted mix.
开级配骨料包含少量矿物质填充料，因此在其骨料颗粒之间具有相对大的空隙。
Coarse-graded aggregates exhibit a continuous grading of sizes but show a predominance of coarse sizes, whereas fine-graded aggregates have a predominance of fine sizes.
粗级配骨料呈现出尺寸上的连续级配，但主要是粗糙尺寸，然而细级配骨料中细尺寸占主要
A coarse aggregate of uniform size, known as a macadam aggregate, received its name from the Scottish engineer John MacAdam, who first used it in an asphalt mix.
相同尺寸的粗级配骨料称之为碎石骨料，由于苏格兰工程师John MacAdam首次在沥青混合料中使用得名。
7When the asphalt concrete is placed, spread and compacted at atmospheric [,ætməs'ferikl] temperature, it is referred to as a cold-laid mixture, in contrast to hot-laid mixtures, which involve elevated temperatures.
当沥青混合料在常温下摊铺和压实时，就被称作冷拌沥青混合料，它和需加热铺筑的热拌沥青混合料不同。 材料特性和比例以及拌制与铺筑条件的结合能使得沥青混凝土按照稳定性、耐久性和弹性呈现不同的特性，以适应各种各样的使用要求。
8It is worth to note that natural deposits of asphalt exist.
值得指出是：在自然界存在着天然沥青矿。
For example, skeletons of prehistoric animals have been preserved in such deposits at the La Brea pit near Los Angeles, CA.
例如，在加利福尼亚州洛杉矶附近的拉布雷亚沉积坑内发现了一些史前动物的骨骼。
Asphalt material was used in Mesopotamia for roadway construction and waterproofing purposes. 在美索不达米亚，沥青材料用于路面施工以及防水目的。
According to the Asphalt Institute, imported rock asphalt was used in Philadelphia, PA in 1838, and the first asphalt pavement was built in Newark, NJ in 1870.
从沥青协会获知，1838年在费城使用过岩石沥青；第一个沥青路面在纽瓦克修建。
Today asphalt is recovered from petroleum in the process of separation/离析 and refinement of constituents
现在的沥青是从石油离析以及提炼得来的。
9Portland cement is mainly a calcium aluminum silicate that is produced by fusing limestone and clay in a rotary kiln to form a clinker material, which is then grind/ground into a fine powder.
波特兰水泥主要是钙—铝—硅酸盐等，它们是在回转炉里融化石灰石和粘土形成渣块材料时生成的，然后又被碾碎成粉末。
First used by an Englishman, Joseph Aspdin, who patented the substance in 1824
英国人Joseph Aspdin首先使用，并于1824年申请专利。
Portland cement derives its name from its ability to react with water and, through hydration/水合作用, to produce an artificial stone that resembles the limestone/石灰石 deposits found on the
波特兰水泥，其名源于与水相互作用和水合作用的能力产生类似在英格兰波特兰岛上发现的石灰石沉积物这种人工石；
It is a " nonbituminous " cement and is classified as a "hydraulic" cement because it solidifies 它是不含沥青的水泥，称之为水力水泥，因为它遇水就凝固。
In various combinations with water, graded mineral aggregates and other admixtures, Portland cement is used to produce numerous construction materials, such as grout, plaster, mortar and Portland cement concrete.
通过调整水、级配矿物骨料以及其他混合物的组成，波特兰水泥可以生产出许多建筑材料，譬如水泥浆、灰泥、砂浆以及混凝土。
By controlling the combinations of the constituents of the mix, a wide variety of desirable characteristics (e. g., strength, durability and workability) can be
obtained to suit particular applications.
通过控制混合物成分的组合，可以得到一系列想要的特性（诸如强度、耐久性、可使用性）来适应特殊的需要。
The most notable characteristic of Portland cement concrete is its compressive strength. It far exceeds its tensile strength, which is only about 10% of its compressive strength.
波特兰水泥混凝土最显著的特点就是它的抗压强度。抗压强度远大于其抗拉强度。抗拉强度只有抗压强度的10%左右；
For this reason Portland-cement concrete pavements are typically designed to resist compressive forces only. The first reported use of Portland-cement concrete for pavement construction in the United States occurred in 1891 in Bellefontaine, OH俄亥俄州.
基于这个原因，波特兰水泥混凝土常设计仅用于抵抗压力；在美国，波特兰水泥混凝土首次用于路面出现在1891年。
10In case prominent tensile forces are present under particularly heavy loads continuous reinforcement with steel bars is applied to withstand the applied tension.
在拉力突出的重型道路上，连续配筋被用来抵抗拉力
Also, prestressing the structural element is another way for taking full advantage （充分利用）of the compressive strength.
此外，对结构单元施加预加力是充分利用抗压强度的另一种方式。
This involves the application, via tendons embedded in the concrete, of a compressive load on the structure prior to applying the service loads.
这包括在承受使用荷载之前，混凝土中植入钢筋束在结构上产生压力荷载
预压应力可抵消荷载产生的拉应力，如此一来，混凝土仍保持受压状态。
Continuously reinforced or prestressed concrete pavements are commonly used for airport runways and aprons.
连续钢筋或者预应力混凝土通常用于机场的跑道和停机坪
11A fundamental difference between asphalt and Portland-cement concrete pavements lies in the fact that the former is characterized by flexibility, whereas the latter provides rigidity.
沥青混凝土和水泥混凝土之间最根本的区别在于，前者主要是以柔性为特点，而后者主要是刚性的
For this reason the two types of pavement are classified, respectively, as flexible and rigid pavements . The following are the corresponding AASHTO definitions.
基于此原因，主要有两类路面，分别是柔性和刚性路面。美国国有公路运输协会的定义如下。 Flexible pavement. A pavement structure which maintains intimate contact with and distributes loads to the subgrade and depends on aggregate interlock, particle friction and cohesion for stability.
柔性路面：是指与路基结合紧密并传递荷载到路基，并且依靠骨料之间的连锁、粒子之间的摩擦和粘结来维持稳定的一种路面结构。
Rigid pavement. A pavement structure which distributes loads to the subgrade, having as one course a Portland-cement concrete slab of relatively high bending resistance.
刚性路面：传递荷载到路基的一种路面结构，并且具有相对较高的抗弯能力。
根据配筋的方法，刚性路面可分为设置或未设置传力杆的素混凝土（无配筋的）路面、传统的加筋水泥混凝土路面、连续配筋水泥混凝土路面和预应力钢筋混凝土路面。
Dowels are steel rods that connect individual pavement slabs to facilitate the transfer of loads between them.
传力杆是一些连接单独混凝土路面板使之联合受力的钢杆。
In the case of continuously reinforced Portland-cement concrete pavements the reinforcing steel serves this function
对于波特兰水泥混凝土路面来说，加筋即可起到这个作用。
在沥青路面上加铺一层波特兰水泥混凝土路面板的复合路面很常见
Moreover, a recent practice of overlaying a Portland-cement concrete layer on old asphalt pavements, called "whitetopping" appears to be gaining in popularity
另外，最近一项称之为白色罩面的路面翻新技术开始变得流行起来。