Construction Method for Road-Pavement

Construction Method for
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
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,
• 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 …
The Rise of Portland Cement
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
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,
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
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
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
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.
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
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
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
Laboratory Exp.
Design of Pavement Materials
Construction of Pavement Structures
Evaluation of Pavement Structures
Maintenance Programs
of Pavement Structures