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Construction Method for Road-Pavement. Introduction of Pavement by : Ms Ikmalzatul. A. History. In its most general sense, a road is an open, generally public way for the passage of vehicles, people, and animals.
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Construction Method for Road-Pavement Introduction of Pavement by : Ms Ikmalzatul
A. History • In its most general sense, a road is an open, generally public way for the passage of vehicles, people, and animals. • The earliest human road builders predate recorded history by thousands of years. With the advent of modern man, road building - the purposeful construction of general public ways - became a common sign of an advancing civilization. • Covering these roads with a hard smooth surface (pavement) helped make them durable and able to withstand traffic and the environment. Some of the oldest paved roads still in existence were built by the Roman Empire.
Roman Roads • By in large, Roman roads (see Figure) were constructed during the Republican times - the oldest road, Via Appia, dates back to 312 B.C. • the Roman road network consisted of over 100,000 km (62,000 miles) of roads. • The superior quality and structure of its pavements have allowed many Roman roads to survive to this day.
The Rise of Bitumen • Tar Macadam Pavements • Road Mix Surfaces • Sheet Asphalt Pavements • Bitulithic Pavements • Others …
The Rise of Portland Cement Concrete • The Original PCC Pavement Portland cement concrete (PCC) was essentially invented in 1824. In 1889, George W. Bartholomew proposed building the first PCC pavement in Bellefontaine, Ohio. Bartholomew was convinced that his "artificial stone" (the term "concrete" had not come into use yet) was a suitable substitute for the brick and cobblestone of the day. In order to convince the city of Bellefontaine to allow him to build his PCC pavement, Bartholomew agreed to donate all the materials and post a $5,000 bond guaranteeing the pavement's performance for five years. In 1891, the first truly rigid pavement was mixed on site and placed in 5 ft. square forms. • Innovations in Performance • Innovations in Construction
Summary Road and pavement building has often been used as a benchmark of a civilizations advancement. The quality and strength of many of the ancient roads has helped them survive to this very day. The Via Appia in Rome is now over 2,300 years old and is still used today. As the use of slave labor declined, smaller more economical roads, such as Telford and Macadam roads, began to arise. Around the beginning of the 19th century, binding agents began to be used to assist aggregate cohesion and improve the durability of roads. By the end beginning of the 20th century, the two principal pavement types, flexible and rigid, had taken on many of their modern qualities and were being built throughout in the world.
B. Pavement Overview • Pavement Purpose Typically, pavements are built for three main purposes: • Load support. Pavement material is generally stiffer than the material upon which it is placed, thus it assists the in situ material in resisting loads without excessive deformation or cracking. • Smoothness. Pavement material can be placed and maintained much smoother than in situ material. This helps improve ride comfort and reduce vehicle operating costs. • Drainage. Pavement material and geometric design can effect quick and efficient drainage thus eliminating moisture problems such as mud and ponding (puddles).
Material Definitions • Hot mix asphalt (HMA). A combination of aggregate and asphalt binder mixed together at elevated temperatures that forms a hard, strong construction material when cooled to ambient temperatures. HMA is known by many names such as "asphalt concrete" (AC or ACP), "asphalt", "blacktop" or "bitumin". HMA is distinguished by its design and production methods and includes traditional dense-graded mixes as well as stone matrix asphalt (SMA) and various open-graded HMAs. Other types of bituminous surfaces (such as slurry seals and bituminous surface treatments) as well as various types of in-place HMA recycling are separate from HMA. • Portland cement concrete (PCC). A combination of aggregate, water and portland cement to form a hard, strong construction material when set. PCC is known by several names including "cement" and "concrete". PCC is distinguished by its design and production methods.
Pavement Types Much of this country relies on paved roads to move themselves and their products rapidly and reliably throughout the transportation system. Pavements can be generally classified into two broad categories: • Flexible pavementsThese are asphalt pavements (sometimes called bituminous pavements), which may or may not incorporate underlying layers of stabilized or unstabilized granular materials on a prepared subgrade. These types of pavements are called "flexible" since the total pavement structure bends (or flexes) to accommodate traffic loads. • Rigid pavementsThese are portland cement concrete (PCC) pavements, which may or may not incorporate underlying layers of stabilized or unstabilized granular materials. Since PCC has a high modulus of elasticity, rigid pavements do not flex appreciably to accommodate traffic loads.
Figures of Pavement In United State of America In Republic of Indonesia
Load Distribution on Pavement Flexible pavements are those which are surfaced with bituminous (or asphalt) materials. These can be either in the form of pavement surface treatments (such as a bituminous surface treatment (BST) generally found on lower volume roads) or, HMA surface courses (generally used on higher volume roads such as the Interstate highway network). 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". On the other hand, rigid pavements are composed of a PCC surface course. Such pavements are substantially "stiffer" than flexible pavements due to the high modulus of elasticity of the PCC material. Further, these pavements can have reinforcing steel, which is generally used to reduce or eliminate joints.
Surface Course The surface course is the layer in contact with traffic loads and normally contains the highest quality materials. It provides characteristics such as friction, smoothness, noise control, rut and shoving resistance and drainage. In addition, it serves to prevent the entrance of excessive quantities of surface water into the underlying base, subbase and subgrade (NAPA, 2001). This top structural layer of material is sometimes subdivided into two layers (NAPA, 2001): • Wearing Course. This is the layer in direct contact with traffic loads. It is meant to take the brunt of traffic wear and can be removed and replaced as it becomes worn. A properly designed (and funded) preservation program should be able to identify pavement surface distress while it is still confined to the wearing course. This way, the wearing course can be rehabilitated before distress propagates into the underlying intermediate/binder course. • Intermediate/Binder Course. This layer provides the bulk of the HMA structure. It's chief purpose is to distribute load.
Base Course The base course is immediately beneath the surface course. It provides additional load distribution and contributes to drainage and frost resistance. Base courses are usually constructed out of: • Aggregate. Base courses are most typically constructed from durable aggregates (see Figure 2.5) that will not be damaged by moisture or frost action. Aggregates can be either stabilized or unstabilized. • HMA. In certain situations where high base stiffness is desired, base courses can be constructed using a variety of HMA mixes. In relation to surface course HMA mixes, base course mixes usually contain larger maximum aggregate sizes, are more open graded and are subject to more lenient specifications.
Subbase Course The subbase course is between the base course and the subgrade. It functions primarily as structural support but it can also: • Minimize the intrusion of fines from the subgrade into the pavement structure. • Improve drainage. • Minimize frost action damage. • Provide a working platform for construction. The subbase generally consists of lower quality materials than the base course but better than the subgrade soils. A subbase course is not always needed or used. For example, a pavement constructed over a high quality, stiff subgrade may not need the additional features offered by a subbase course so it may be omitted from design. However, a pavement constructed over a low quality soil such as a swelling clay may require the additional load distribution characteristic that a subbase course can offer. In this scenario the subbase course may consist of high quality fill used to replace poor quality subgrade (over excavation).
Flexible Pavement Types There are many different types of flexible pavements. This section covers three of the more common types of HMA mix types used. This section provides a brief exposure to: • 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. • 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. • 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.
ROAD CONSTRUCTION Aggregates Asphalt/PCC Laboratory Exp. Design of Pavement Materials Construction of Pavement Structures Evaluation of Pavement Structures Maintenance Programs of Pavement Structures
