Construction Method for Road-Pavement Lecture 1 Introduction of Pavement by : Sri Atmaja P. Rosyidi 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. … Roman Roads A typical Roman road structure (see Figure), as seen in the United Kingdom, consisted of four basic layers (Collins and Hart, 1936): • Summa Crusta (surfacing). Smooth, polygonal blocks embedded in the underlying layer. • Nucleus. A kind of base layer composed of gravel and sand with lime cement. • Rudus. The third layer was composed of rubble masonry and smaller stones also set in lime mortar. • Statumen. Two or three courses of flat stones set in lime mortar. Telford Pavements The first insight into today's modern pavements can be seen in the pavements of Thomas Telford (born 1757). Teleford served his apprenticeship as a building mason (Smiles, 1904) and extended his masonry knowledge to bridge building. During lean times, he carved gravestones and other ornamental work (about 1780). Eventually, Telford became the "Surveyor of Public Works" for the county of Salop (Smiles, 1904), thus turning his attention more to roads. Telford attempted, where possible, to build roads on relatively flat grades (no more than a 1 in 30 slope) in order to reduce the number of horses needed to haul cargo. … Telford Pavements Telford's pavement section was about 350 to 450 mm (14 to 18 inches) in depth and generally specified three layers. The bottom layer was comprised of large stones 100 mm (4 inches) wide and 75 to 180 mm (3 to 7 inches) in depth (Collins and Hart, 1936). It is this specific layer which makes the Telford design unique (Baker, 1903). On top of this were placed two layers of stones of 65 mm (2.5 inches) maximum size (about 150 to 250 mm (6 to 9 inches) total thickness) followed by a wearing course of gravel about 40 mm (1.6 inches) thick (see Figure). It was estimated that this system would support a load corresponding to about 88 N/mm (500 lb per in. of width). … Telford Pavements Macadam Pavements Macadam pavements introduced the use of angular aggregates. John MacAdam (born 1756 and sometimes spelled "Macadam") observed that most of the paved U.K. roads in early the 1800s were composed of rounded gravel (Smiles, 1904). He knew that angular aggregate over a well-compacted subgrade would perform substantially better. He used a sloped subgrade surface to improve drainage (unlike Telford who used a flat subgrade surface) on which he placed angular aggregate (hand-broken with a maximum size of 75 mm (3 inches)) in two layers for a total depth of about 200 mm (8 inches) (Gillette, 1906). On top of this, the wearing course was placed (about 50 mm thick with a maximum aggregate size of 25 mm) (Collins and Hart, 1936). Macadam's reason for the 25 mm (1 inch) maximum aggregate size was to provide a "smooth" ride for wagon wheels. … Macadam Pavements The total depth of a typical MacAdam pavement was about 250 mm (10 inches) (refer to Figure 1.5). MacAdam was quoted as saying "no stone larger than will enter a man's mouth should go into a road" (Gillette, 1906). The largest permissible load for this type of design has been estimated to be 158 N/mm (900 lb per in. width). In 1815, Macadam was appointed "surveyor-general" of the Bristol roads and was then able to use his design on numerous projects. It proved successful enough that the term "macadamized" became a term for this type of pavement design and construction. The term "macadam" is also used to indicate "broken stone" pavement (Baker, 1903). … Macadam Pavements The Rise of Bitumen Tar Macadam Pavements Road Mix Surfaces Sheet Asphalt Pavements Bitulithic Pavements Others … ASSIGNMENT : WRITE THE DESCRIPTION OF ABOVE ITEMS AND THE MODERN KINDS (RECENT USED) OF PAVEMENT AFTER THE RISE OF THE BITUMEN 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: 1. 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. 2. Smoothness. Pavement material can be placed and maintained much smoother than in situ material. This helps improve ride comfort and reduce vehicle operating costs. 3. Drainage. Pavement material and geometric design can effect quick and efficient drainage thus eliminating moisture problems such as mud and ponding (puddles). Material Definitions 1. 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. 2. 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. 3. Concrete. Term often used to describe portland cement concrete. However, in its more generic form "concrete" refers to any conglomeration or coalescence of materials usually held together by a binding substance. Thus, asphalt concrete and portland cement concrete are two types of concrete with the "asphalt" and "portland cement" referring to the binding material. 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: 1. Flexible pavements These 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. 2. Rigid pavements These 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 The FHWA also identifies a third type of pavement, called a composite pavement. Composite pavements are combination HMA and PCC pavements. Occasionally, they are initially constructed as composite pavements, but more frequently they are the result of pavement rehabilitation (e.g., HMA overlay of PCC pavement). Modeling these pavements depends on the composite action. For instance, an HMA overlay of rubblized PCC is typically classified as a flexible pavement, while an HMA overlay of a PCC pavement with no fracture preparation typically responds with rigid pavement characteristics (see Figure). Officially, the FHWA "composite pavement" category is defined as a "mixed bituminous or bituminous penetration roadway" of more than 25 mm (1 inch) of compacted material on a rigid base (FHWA, 2001) The overlying HMA The underlying PCC slabs 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. Flexible Pavement Each of these pavement types distributes load over the subgrade in a different fashion. Rigid pavement, because of PCC's high elastic modulus (stiffness), tends to distribute the load over a relatively wide area of subgrade (see Figure). 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). Basic Structural Elements A typical flexible pavement structure (see Figure) consists of the surface course and the underlying base and subbase courses. Each of these layers contributes to structural support and drainage. The surface course (typically an HMA layer) is the stiffest (as measured by resilient modulus) and contributes the most to pavement strength. The underlying layers are less stiff but are still important to pavement strength as well as drainage and frost protection. A typical structural design results in a series of layers that gradually decrease in material quality with depth. 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): 1.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. 2.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: 1. 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. 2. 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. 1. 2. 3. 4. 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). Perpetual Pavements "Perpetual Pavement" is a term used to describe a long-lasting structural design, construction and maintenance concept. A perpetual pavement can last 50 years or more if properly maintained and rehabilitated. As Michael Nunn pointed out in 1998, flexible pavements over a minimum strength are not likely to exhibit structural damage even when subjected to very high traffic flows over long periods of time. He noted that existing pavements over about 370 mm (14.5 inches) should be able to withstand an almost infinite number of axle loads without structural deterioration due to either fatigue cracking or rutting of the subgrade. Deterioration in these thick, strong pavements was observed to initiate in the pavement surface as either top-down cracking or rutting. Further, Uhlmeyer et al. (2000) found that most HMA pavements thicker than about 160 mm (6.3 inches) exhibit only surface-initiated top-down cracking. Therefore, if surface-initiated cracking and rutting can be accounted for before they impact the structural integrity of the pavement, the pavement life could be greatly increased. 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 wellunderstood 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). Opengraded mixes are typically used as wearing courses (OGFC) or underlying drainage layers (ATPM) because of the special advantages offered by their porosity. Example of Flexible Pavement STONE MATRIX ASPHALT (SMA) ROAD CONSTRUCTION Aggregates Asphalt/PCC BAHAN PERKERASAN JALAN Laboratory Exp. Design of Pavement Materials METODE PELAKSANAAN PERKERASAN JALAN Construction of Pavement Structures Evaluation of Pavement Structures Maintenance Programs of Pavement Structures MANAJEMEN PERKERASAN JALAN ASSIGNMENT : WRITE THE DESCRIPTION OF THE SEVERAL KINDS (RECENT USED) OF FLEXIBLE PAVEMENT USED IN INDONESIA.