Comprative Analysis Of Highway Design

COMPARATIVE ANALYSIS OF HIGHWAY DESIGN AN END SEMESTER THESIS REPORT SUBMMITED IN PARTIAL FULFILLMENT OF THE REQUIREMENT FOR THE DEGREE OF MASTER OF TECHNOLOGY IN HIGHWAY ENGINEERING

BY ARUN KUMAR BHARTI

(15-MTH-1154) UNDER THE GUIDENCE OF

Prof. SHIVAM SINGH PATEL

DEPARTMENT OF CIVIL ENGINEERING MAHARISHI UNIVERSITY OF INFORMATION TECHNOLOGY LUCKNOW-226013 JUNE-2017

Certificate This is to certify that the report entitled, “Comparative Analysis of Highway design”, submitted by Arun Kumar Bhartito Maharishi University of Information Technology Lucknow, for partial fulfillment of award of the degree Master of Technology in Highway Engineeringis a record of bonafide work carried out by him under my supervision and guidance. To the best of my knowledge, the results embodied in this thesis have not been submitted to any other University or Institute for the award of any other Degree or Diploma.

Assistant Prof. Shivam singh Patel Department of civil engineering

Acknowledgements First of all, I would like to express my profound gratitude to my guide, Assistant Prof. Shivam Patel, for his outstanding guidance and support during my dissertation work. I benefited greatly from working under his guidance. His encouragement,

motivation,

and

support

have

been

invaluable throughout my studies at Maharishi University of Information Technology Lucknow. Special

thanks to

Assistant Prof.

Shashishekhar.

andProf.Dr.S.r. Ali, who were the examiners for my thesis work. Their comments have helped me a lot in understanding of concepts clearly. I would like to express my gratitude towards my parents for the encouragement which helped me to complete my M.tech studies. I also would like to thank my friend Mohit Kumar Bharti for his support in my project work.

Arun Kumar Bharti

Abstract New highway design construction and its maintenance are one of the most vital application of civil engineering while carrying out of a new road construction ,essential of civil engineering fundamental such as surveying ,technology used ,earth work compaction ,grading ,of the road surface etc. Are assured and carried out very meticulously .in forthcoming chapters an attempt has made to compared topic such as lying of WBM layer ,WMM layer which part of my project work .

Different design method used in highway design construction. geometric design method ,pavement design method ,rigid pavement design studies and continuously work under going changes .in coming maintenance and testing of the road are also include in proceeding chapters .these are not my academic curriculum but also were the main my training work and project work

Table of contents Title

Page no.

1. Certificate from guide .....................................................................1 2. Acknowledgement ………….................................................................2 3. Abstract……………………………………...................................................... 3 4. List of figures (a) .lane width for single and two lane roads. (b). Sight distance. (c). Alignment of roads. (d). Aggregates, soil. (e). Fatigue cracking on road surface. (f). Rutting on road surface. (g). Highway drainage design. (h). subbase and base course. (i). Pcc use in highway. (j). Maintenance of highway. 5.List of table………………………………………………………………

CHAPTER - 1

Introduction..................................................................... 1.1 1.2 1.3 1.4 1.5 1.6

History……………………………………………………………………………. Planning and development............................................... Financing.......................................................................... Highway safety…………………………………………………………………… Design................................................................................ Requirement of pavements…………………………………………………

CHAPTER -2 2. Asphalt or flexible pavement design............................................... 2.1. Asphalts pavement compositions………………………………………………….. 2.2. Advantages of asphalt or flexible ……………………………………………….. CHAPTER-3 3. Geometric design..................................................................... 3.1. Geometric design of highway deals with following element…………... 3.2. cross section..................................................................... 3.3. Elements of cross section................................................. 3.4. Kerbs………………………………………………………………………………… 3.5. Sight distance.................................................................. 3.6. Highway alignment............................................................ CHAPTER-4 4.Highway material and tests………………………………………………………

4.1. Components of highway………………………………………………………… 4.2. Used of material in highway………………………………………………. 4.3. Test of highways…………………………………………………………. CHAPTER-5 5. Rigid pavement design............................................................ CHAPTER-6 6. Pavement structural design...................................................... 6.1. Types of failure............................................................... 6.2. Fatigue....................................................... 6.3. Rutting…………………………………………........................................ 6.4. Flexible pavement overlay design……………………………………………. 6.5. Rigid pavement overlay design…………………………………………………… 6.6. Drainage system design……………………………………………………………….. CHAPTER-7 7. Highway constructionmaintenance, andmanagement............... 7.1. Highway construction................................................ 7.2. Subbase course construction...................................... 7.3. Base course construction............................................. 7.4. Surface course construction…………………………………………… 7.5. Hot mix asphalt layer………………………………………………………

7.6. Portland cement concrete……………………………………………….. 7.7. Highway maintenance…………………………………………………….. 7.8. Project management………………………………………………………. 8. CONCLUSION 9. REFERENCES

Chapter:-1 Introduction Highway engineering is an engineering discipline branching from civil engineering that involves the planning, design, construction, operation, and maintenance of roads, bridges, and tunnels to ensure safe and effective transportation of people and goods. Highway engineering became prominent towards the latter half of the 20th Century after World War 2. Standards of highway engineeringare continuously being improved. Highway engineers must take into account future traffic flows, design of highway intersections/interchanges, geometric alignment and design, highway pavement materials and design, structural design of pavement thickness, and pavement maintenance. 1.1. History The beginning of road construction could be dated to the time of the Romans. With the advancement of technology from carriages pulled by two horses to vehicles with power equivalent to 100 horses, road development had to follow suit. The construction of modern highways did not begin until the late 19th to early 20th century.[ The first research dedicated to highway engineering was initiated in the United Kingdom with the introduction

ofthe Transport Research Laboratory (TRL), in 1930.In the USA, highway engineering became an important discipline with the passing of the Federal-Aid Highway Act of 1944, which aimed to connect 90% of cities with a population of 50,000 or more. With constant stress from vehicles which grew larger as time passed, improvements to pavements were needed. With technology out of date, in 1958 the construction of the first motorway in Great Britain (the Preston bypass) played a major role in the development of new pavement technology. Design policies standards used in the United States are typically based on publications of the American Association of State Highway and Transportation Officials as well as research promulgated by the Transportation Research Board, the Institute of Transportation Engineers, the Federal Highway Administration, and the Department of Transportation. 1.2. Planning and development Highway planning involves the estimation of current and future traffic volumes on a road network. Highway engineers strive to predict and analyze all possible civil impacts of highway systems. Some considerations are the adverse effects on the environment, such as noise pollution, air pollution, water pollution, and other ecological impacts. 1.3. Financing

Developed countries are constantly faced with high maintenance cost of aging transportation highways. The growth of the motor vehicle industry and accompanying economic growth has generated a demand for safer, better performing, less congested highways. The growth of commerce, educational institutions, housing, and defense have largely drawn from government budgets in the past, making the financing of public highways a challenge. The multipurpose characteristics of highways, economic environment, and the advances in highway pricing technology are constantly changing. Therefore, the approaches to highway financing, management, and maintenance are constantly changing as well 1.4. Highway safety Highway systems generate the highest price in human injury and death, as nearly 50 million persons are injured in traffic accidents every year, not including the 1.2 million deaths. Road traffic injury is the single leading cause of unintentional death in the first five decades of human life. Management of safety is a systematic process that strives to reduce the occurrence and severity of traffic accidents. The machine interaction with road traffic systems is unstable and poses a challenge to highway safety management. The key for increasing the safety of highway systems is to design, build, and

maintain them to be far more tolerant of the average range of this machine interaction with highways. Technological advancements in highway engineering have improved the design, construction, and maintenance methods used over the years. These advancements have allowed for newer highway safety innovations. By ensuring that all situations and opportunities are identified, considered, and implemented as appropriate, they can be evaluated in every phase of highway planning, design, construction, maintenance, and operation to increase the safety of our highway systems. 1.5. Design The most appropriate location, alignment, and shape of a highway are selected during the design stage. Highway design involves the consideration of three major factors (human, vehicular, and roadway) and how these factors interact to provide a safe highway. Human factors include reaction time for braking and steering, visual acuity for traffic signs and signals, and car-following behavior. Vehicle considerations include vehicle size and dynamics that are essential for determining lane width and maximum slopes, and for the selection of design vehicles. Highway engineers design road geometry to ensure stability of vehicles when negotiating curves and grades and to provide adequate sight distances for

undertaking passing maneuvers along curves on two-lane, twoway roads. 1.2. of Requirements a pavement The pavement should meet the following requirements:  sufficient thickness to distribute the wheel load stresses to a safe value on the subgrade soil Structurally strong to withstand all types of stresses imposed upon it  Adequate coefficient of friction to prevent skidding of vehicles.  Smooth surface to provide comfort to read users even at highspeed.  Dust proof surface so that traffic safety is not impaired by reducing visibility.  impervious surface, so that subgrade is well protected Long design life with low maintenance.

Chapter:- 2 2. Asphalt pavement Design From some years ago, asphalt has been playing an important role in our daily activities. We don’t even think about it, but when we go to any place or when we buy something, asphalt roads are being used. The European road network consists of about 6.1 million kilometers of paved roads, andabout 90% of all these roads are paved with asphalt. The other 10% is made of concreteand pavers (bricks, cobblestones, etc.). Asphalt is also used in railway beds,Airportrunways, playgrounds, running tracks, tennis courts, bridges, tunnels, etc. Roads are the most used mode of transport. Over 72% of our inland goods and 83% of Passengers’travels are done by road, rather than rail, air or water, so here it is show theimportance of roads. 2.1 Asphalt pavement composition Asphalt is a mixture of aggregates, binder and filler. Aggregates used for asphalt couldbe crushed rock, sand, gravel or slags. In order to get all the aggregates joined into acohesive mixture, bitumen is used as a binder. The common asphalt pavement designconsists on different layers. The bottom layer is the existing soil or sub-grade.

The nextlayer is an aggregate base layer which sometimes is stabilized with asphalt, cement orfly ash. Then, this is followed by one or more layers of asphalt pavement. The main objective of these layers is to give the pavement the ability to distribute the loads of the traffic, stresses and strains generated, before it arrives at the foundationlevel. Also, the viscous nature of the bitumen allows the pavement structure to sustain significant plastic deformation, although fatigue from repeated loading is the mostcommon failure mechanism. 2.2 Advantages of asphalt Asphalt pavement surfaces offer a lot of benefits Smoothness and comfort ability:- the construction way of multiple layerpavements provides and structure completely smooth, which gives the user thatsense of comfort when they use the road. 2.2.1. Cost-efficient structure: asphalt has low initial costs, lasts long, and due to itsrecyclability, has greater residual value than other pavements. Porous asphaltpavements are made so that water can drain through the pavement. Also, usingAsphalt surfaces can significantly reduce the noise inside and outside the vehicle.

2.2.2.Safety:- asphalt structures provides a fast drainage of surface water in order toAvoid floods, and consequently aquaplaning, and provide better visibility todrivers in these conditions. Also, it gives more grip to the vehicle wheels for notslipping from the pavements. 2.2.3. Durability:- roads are commonly designed to last about 15-20 years, dependingOn the traffic it is supposed to suffer. When the wearing course has to bereplaced, the old one is reused into a new asphalt layer. Some properly designedAnd maintained roads may be more time without needing total reconstruction. 2.2.4. Fast construction: asphalt pavement don’t need “cure” time, so constructiontime is short and there are fewer delays for the traffic during the construction. - Reusability: asphalt is one of the most recycling construction products in Europe, so less bitumen has to be used in the reconstruction of roads. - Flexibility: roads can be designed to cope with any traffic load and climate conditions.

Chapter:- 3 3.Geometric design of highways The geometric design of roads is the branch of highway engineering concerned with the positioning of the physical elements of the roadway according to standards and constraints. The basic objectives in geometric design are to optimize efficiency and safety while minimizing cost and environmental damage. Geometric design also affects an emerging fifth objective called "livability," which is defined as designing roads to foster broader community goals, including providing access to employment, schools, businesses and residences, accommodate a range of travel modes such as walking, bicycling, transit, and automobiles, and minimizing fuel use, emissions and environmental damage. It is possible to design and construct the pavement of road design in stagesbut it is very expensive and rather difficult to improve the geometric elements of a road in stages at a later date .

3.1. Geometric design of highways deals with following elements :

(a). cross section elements (b). sight distance consideration (c). horizontal alignment details (d). vertical alignment details (e). intersection elements

3.2.(a).cross section:The cross section of a roadway can be considered a representation of what one would see if an excavator dug a trench across a roadway, showing the number of lanes, their widths and cross slopes, as well as the presence or absence of shoulders, curbs, sidewalks, drains, ditches, and other roadway feature. 3.3. Elements of cross section  Camber:- is the cross slope provided to raise middle of the road surface in the transverse direction to drain off rain water from road surface. The objectives of providing camber are: • Surface protection especially for gravel and bituminous roads • Sub-grade protection by proper drainage • Quick drying of pavement which in turn increases safety

Too steep slope is undesirable for it will erode the surface. Camber is measured in 1 in n or n% (Eg. 1 in 50 or2%) and the value depends on the type of pavement surface. The values suggested by IRC for various categories of pavement is given in figure. The common types of camber are parabolic, straight, or combination of them. Width of pavement orcarriageway:The width of pavements or carriageway depends upon(1) width of traffic lane and (2) numbers of lanes.the lane width to 3.75m if there is raised kerbsuch as foot path of urban roads. Width of a traffic lane depends on the width of the vehicle and the clearance. Side clearance improves operating speed and safety. The maximum permissible width of a vehicle is 2.44 and the desirable side clearance for single lane traffic is 0.68 m. This require minimum of lane width of 3.75 m for a single lane road. the side clearance required is about 0.53 m, on either side and 1.06 m in the center. Therefore, a two lane

Table 1: IRC Specification for carriage way width Single lane

3.75

Two lane, no kerbs

7.0

Two lane, raised kerbs

7.5

Intermediate carriage

5.5

Multi-lane

3.5



Figure 1: Lane width for single and two lane roads

3.4.Kerbs:-Kerbs indicate the boundary between the carriage way and the shoulder or islands or footpaths. Different types of kerbs are • Low or mountable kerbs:This type of kerbs is provided such that they encourage the traffic to remain in the through traffic lanes and also allow the driver to enter the shoulder area with little difficulty. The height of this kerb is about 10 cm above the pavement edge with a slope which allows the vehicle to climb easily. This is usually provided

at medians and channelization schemes and also helps in longitudinal drainage. • Semi-barrier type kerbs: When the pedestrian traffic is high, these kerbs are provided. Their height is 15 cm above the pavement edge. This type of kerb prevents encroachment of parking vehicles, but at acute emergency it is possible to drive over this kerb with some difficulty. • Barrier type kerbs: They are designed to discourage vehicles from leaving the pavement. They are provided when there is considerable amount of pedestrian traffic. They are placed at a height of 20 cm above the pavement edge with the step better.

Fig: - kerbsuse in pavement

3.5.SIGHTDISTANCE:-The safe and efficient operation of vehicles on the road depends very much on the visibility of the road ahead ofthe driver. Thus the geometric design of the road should be done such that any obstruction on the road lengthcould be visible to the driver from some distance ahead. This distance is said to be the sight distance.  Types of sight distance: Sight distance available from a point is the actual distance along the road surface, over which a driver froma specified height above the carriage way has visibility of stationary or moving objects. Three sight distancesituations are considered for design:  • Stopping sight distance (SSD) or the absolute minimum sight distance  • Intermediate sight distance (ISD) is defined as twice SSD  • Overtaking sight distance (OSD) for safe overtaking operation  Head light sight distance is the distance visible to a driver during night driving under the illumination ofhead lights.  • Safe sight distance to enter into an intersection.  The most important consideration in all these is that at all times the driver traveling at the design speed

 





ofthe highway must have sufficient carriageway distance within his line of vision to allow him to stop his vehiclebefore colliding with a slowly moving or stationary object appearing suddenly in his own traffic lane. The computation of sight distance depends on Reaction time of the driver. Reaction time of a driver is the time taken from the instant the object is visible to the driver to theinstant when the brakes are applied. The total reaction time may be split up into four components basedon PIEV theory. In practice, all these times are usually combined into a total perception-reaction timesuitable for design purposes as well as for easy measurement. Many of the studies show that driversrequire about 1.5 to 2 sec under normal conditions. However, taking into consideration the variability. Speed of the vehicle:-The speed of the vehicle very much affects the sight distance. Higher the speed, more time will be required to stop the vehicle.

fig:- sight distance

Fig:- sight distance intersection

3.6.Highway alignment:- the position of the layout of the Centre line of the highway on the ground is called the alignment .Highway alignment includes both horizontal and

vertical alignment of roadway. The horizontal alignment includes the straight path, the deviations and horizontal curves. Changes in gradient and vertical curves are covered under vertical alignment of roads.

Figure:- alignment to roads

CHAPTER:-4 4. Highway material and tests :-

The materials used for roadway construction have progressed with time, dating back to the early days of the Roman Empire. Advancements in methods with which these materials are characterized and applied to pavement structural design has accompanied this advancement in materials.  There are two major types of pavement surfaces (a). Portland cement concrete (PCC) (b). hot-mix asphalt (HMA).  This wearing course is material layers that give structural support for the pavement system. These underlying surfaces may include either the aggregate base and sub base layers, or treated base and sub base layers, and additionally the underlying natural or treated subgrade.  These treated layers may be cement-treated, asphalt-treated, or lime-treated for additional support.  4.1. Components of highway :2. (a). Embankment or fill 2. (b). Subgrade 2. (c). Pavement layer of flexible or rigid structure  4.2. used of material in highway:-

a. Soil – used fill or embankment proper inhighway. b. Stone aggregates- Aggregate is the component of a composite material that resists compressive stress and provides bulk to the composite material.  For efficient filling, aggregate should be much smaller than the finished item, but have a wide variety of sizes.  The particles of stone used to make concrete typically include both sand and gravel.  The aggregates are specified based on their grain size, shape, texture and its gradation. The required aggregates sizes are chosen to fulfill the desired gradation. The grading, tests and specification of stone aggregates for different road making purposes have been specified by various agencies like the IRC, BIS, ASTM and BSI.  Hard aggregates: - are preferred to resist the abrading and crushing effects of heavy traffic loads and to resist adverse weather conditions.  Softaggregates:- such as moorum, kankar, laterite, bricks aggregates and slag have been used in the lower layer of road pavement structure. A different

set of tests and specifications are adfor soft aggregates.

Fig:- aggregates

4.3.Tests of highway:-

1. Aggregates impact test- to access the toughness or resistance to impact.Sieves of sizes – 12.5mm, 10mm and 2.36mm, a cylindrical metal measure of 75mm dia. and 50mm depth, a tamping rod of 10mm circular cross section and 230mm length, rounded at one end and Oven. The sample should be oven-dried for 4hrs. at a temperature of 100 to 110oC and cooled.

Aggregate impact value = (B/A) x 100% 2. Aggregates crushing test(i) The aggregates passing through 12.5mm and retained on 10mm IS Sieve are oven-dried at a temperature of 100 TO110oc 3 to 4hrs. (ii) The cylinder of the apparatus is filled in 3 layers, each layer tamped with 25 strokes of a tamping rod. (iii) The weight of aggregates is measured (Weight ‘A’). (iv) The surface of the aggregates is then leveled and the plunger inserted. The apparatus is then placed in the compression testing machine and loaded at a uniform rate

so as to achieve 40t load in 10 minutes. After this, the load is released. (v) The sample is then sieved through a 2.36mm IS Sieve and the fraction passing through the sieve is weighed (Weights’’). (vi) Two tests should be conducted.

Aggregate crushing value = (B/A) x 100% 3. Aggregates Abrasion testThe test sample and the abrasive charge should be placed in the Los Angles abrasion testing machine and the machine rotated at a speed of 20 to 33 revolutions/minute for 1000 revolutions. At the completion of the test, the material should be discharged and sieved through 1.70mm IS Sieve.

Aggregate abrasion value = (A-B)/B x 100% 4. Cement fineness test(i) Weigh approximately 10g of cement to the nearest 0.01g and place it on the sieve. (ii) Agitate the sieve by swirling, planetary and linear movements, until no more fine material passes through it. (iii) Weigh the residue and express its mass as a percentage R1, of the quantity first placed on the sieve to the nearest 0.1 percent. (iv) Gently brush all the fine material off the base of the sieve. (v) Repeat the whole procedure using a fresh 10g sample to obtain R2. Then calculate R as the mean of R1 and R2 as a percentage, expressed to the nearest 0.1 percent. When the results differ by more than 1 percent absolute, carry out a third sieving and calculate the mean of the three values.

Fig- sieve use in cement fineness test

5. Sieve analysis test-

(i) A set of IS Sieves of sizes – 80mm, 63mm, 50mm, 40mm,31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 6.3mm,4.75mm, 3.35mm, 2.36mm, 1.18mm, 600µm, 300µm, 150µm and 75µm. (ii) Balance or scale with an accuracy to measure 0.1 percent of the weight of the test sample.

Fig-sieve analysis

6. Specific gravity of soil testSpecific gravity is the ratio of the weight in air of a given volume of a material at a standard temperature to the weight in air of an equal volume of distilled water at the same stated temperature.

The specific gravity G of the soil = (W2 – W1) / [(W4–1)-(W3W2)]. 7.Waterabsorption testThis test helps to determine the water absorption of coarse aggregates as per IS: 2386 (Part III) – 1963. For this test a sample not less than 2000g should be used.  The apparatus used for this test are:Wire basket – perforated, electroplated or plastic coated with wire hangers for suspending it from the balance, Water-tight container for suspending the basket, Dry soft absorbent cloth – 75cm x 45cm (2 nos.), Shallow tray of minimum 650 sq.cm area, Air-tight container of a capacity similar to the basket and Oven. Formula used is Water absorption = [(A – B)/B] x 100%. 8. Penetration Bitumen test The principle is that the penetration of a bituminous material is the distance in tenths of a mm, that a standard needle would penetrate vertically, into a sample of the material under standard conditions of temperature, load and time. The apparatus needed to determine the penetration of bitumen is (i).Penetrometer

(ii).Water bath (iii).Bath thermometer- Range 0 to 440C ,Graduation 0.20C

fig- penetration test apparatus

(i). Soften the bitumen above the softening point (between 75 and 100oC). Stir it thoroughly to remove air bubbles and water. (ii) Pour it into a container to a depth of at least 15mm in excess of the expected penetration. (iii) Cool it at an atmospheric temperature of 15 to 30oC for 11/2 hours. Then place it in a transfer dish in the water bath at 25.0 + 0.1oC for 11/2 hrs. (iv) Keep the container on the stand of the penetration apparatus.

(v) Adjust the needle to make contact with the surface of the sample. (vi) Adjust the dial reading to zero. (vii) With the help of the timer, release the needle for exactly 5 seconds. Chapter:-5 Rigid pavement design Rigid pavements are generally used in constructing airports and major highways, such as those in the interstate highway system. In addition, they commonly serve as heavy-duty industrial floor slabs, port and harbor yard pavements, and heavy-vehicle park or terminal pavements. Like flexible pavements, rigid highway pavements are designed as allweather, long-lasting structures to serve modern day highspeed traffic. Offering high quality riding surfaces for safe vehicular travel, they function as structural layers to distribute vehicular wheel loads in such a manner that the induced stresses transmitted to the subgrade soil are of acceptable magnitudes. 5.1. Portland cement concrete (PCC):- is the most common material used in the construction of rigid pavement slabs. The reason for its popularity is due to its availability and the economy. Rigid pavements must be designed to

endure frequently repeated traffic loadings. The typical designed service life of a rigid pavement is between 30 and 40 years, lasting about twice as long as a flexible pavement.  One major design consideration of rigid pavements is reducing fatigue failure due to the repeated stresses of traffic. Fatigue failure is common among major roads because a typical highway will experience millions of wheel passes throughout its service life. In addition to design criteria such as traffic loadings, tensile stresses due to thermal energy must also be taken into consideration. As pavement design has progressed, many highway engineers have noted that thermally induced stresses in rigid pavements can be just as intense as those imposed by wheel loadings. Due to the relatively low tensile strength of concrete, thermal stresses are extremely important to the design considerations of rigid pavements. Rigid pavements are generally constructed in three layers - a prepared subgrade, base or subbase, and a concrete slab. The concrete slab is constructed according to a designed choice of plan dimensions for the slab panels, directly influencing the intensity of thermal stresses occurring within the pavement. In

addition to the slab panels, temperature reinforcements must be designed to control cracking behavior in the slab. Joint spacing is determined by the slab panel dimensions. 5.2. Three main types of concrete pavements commonly used are jointed plain concrete pavement (JPCP), jointed reinforced concrete pavement (JRCP), and continuously reinforced concrete pavements (CRCP). JPCP’s are constructed with contraction joints which direct the natural cracking of the pavement. These pavements do not use any reinforcing steel. JRCP’s are constructed with both contraction joints and reinforcing steel to control the cracking of the pavement. High temperatures and moisture stresses within the pavement creates cracking, which the reinforcing steel holds tightly together. At transverse joints, dowel bars are typically placed to assist with transferring the load of the vehicle across the cracking. CRCP’s solely rely on continuous reinforcing steel to hold the pavement’s natural transverse cracks together.  Prestressed concrete pavements have also been used in the construction of highways; however, they are not as common as the other three.  Prestressed pavements allow for a thinner slab thickness by partly or wholly neutralizing thermally induced stresses or loadings.

Fig:- layer of rigid pavement

fig:- reinforcement use rigid pavement

Chapter:-6 Pavement structure design 6.1. Types of failure Pavement performance is normally evaluated using fatigue cracking and rutting models. These models are primarily caused by stresses and strains due to repetitions of high traffic loading. Factors such as temperature, moisture, ageing, material mix design, etc. also affect to pavement distress, although we won’t talk about them. 6.2.Fatigue  Fatigue cracking is the progressive cracking of the asphalt surfacing or stabilized base layers due to cumulative repeated traffic loading. This occurs as a result of tensile stresses and strains in the bottom zone of asphalt layer and propagates upward to the top.  On the pavement surface, it finally appears as alligator/crocodile cracks along wheel tracks, as we appreciate in the

Fig:- fatigue cracking on the road surface

Fatigue cracking in asphalt layers is considered a major structural distress and is predominantly caused by traffic loading. Moreover, the effect of rain water the roughs the cracks can lead to serious structural failureofunderlyinglayers particularly granular andunbound materials including the subgrade. Logarithmic equations are normally used to obtain number of load repetitions to failure cracking, taking into account tensile stresses or strains and some other parameters depending on the modal used. 6.3.Rutting:-

 Rutting is defined as the permanent deformation of a pavement due to the accumulation of visco-plastic vertical compressive strains under traffic loading. This is the manifestation of gradual densification of pavement layers, and shear displacement of the subgrade. On the pavement surface, it looks like as longitudinal depressions inthe wheel tracks, as we see in the Figure Significant rutting can lead to major structural failure and hydroplaning potentials.

fig:-rutting on road surface

6.4.Flexible pavement overlay design 

Over the service life of a flexible pavement, accumulated traffic loads may cause excessive rutting or cracking, inadequate ride quality, or an inadequate skid resistance. These problems can be avoided by adequately maintaining the pavement, but the solution usually has excessive maintenance costs, or the pavement may have an in Adequate structural capacity for the projected traffic loads.  Throughout a highway’s life, its level of serviceability is closely monitored and maintained. One common method used to maintain a highway’s level of serviceability is to place an overlay on the pavement’s surface.  There are three general types of overlay used on flexible pavements: Asphalt-concrete overlay, Portland cement concrete overlay, and ultra-thin Portland cement concrete overlay. The concrete layer in a conventional PCC overlay is placed unbounded on top of the flexible surface. The typical thickness of an ultra-thin PCC overlay is 4 inches (10 cm) or less.

 There are three main categories of flexible pavement overlay design procedures:  Component Analysis Design  Deflection Based Design 6.5.Rigid pavement overlay design  Near the end of a rigid pavement's service life, a decision must be made to either fully reconstruct the worn pavement, or construct an overlay layer. Considering an overlay can be constructed on a rigid pavement that has not reached the end of its service life, it is often more economically attractive to apply overlay layers more frequently. The required overlay thickness for a structurally sound rigid pavement is much smaller than for one that has reached the end of its service life. Rigid and flexible overlays are both used for rehabilitation of rigid pavements such as JPCP, JRCP, and CRCP.  There are three subcategories of rigid pavement overlays that are organized depending on the bonding condition at the pavement overlay and existing slab interface.  Bonded overlays  Unbounded overlays  Partially bonded overlays

6.6.Drainage system design Designing for proper drainage of highway systems is crucial to their success. Regardless of how well other aspects of a road are designed and constructed, adequate drainage is mandatory for a road to survive its entire service life. Excess water in the highway structure can inevitably lead to premature failure, even if the failure is not catastrophic. Each highway drainage system is site-specific and can be very complex. Depending on the geography of the region, many methods for proper drainage may not be applicable. The highway engineer must determine which situations a particular design process should be applied, usually a combination of several appropriate methods and materials to direct water away from the structure.

Fig:-highway drainage design

Chapter:7Construction, maintenance, and management:7.1. Highway construction  Highway construction is generally preceded by detailed surveys and subgrade preparation.  The methods and technology for constructing highways has evolved over time and become increasingly sophisticated. This advancement in technology has raised the level of skill sets required to manage highway construction projects.  This skill varies from project to project, depending on factors such as the project's complexity and nature, the contrasts between new construction and reconstruction, and differences between urban region and rural region projects. There are a number of elements of highway construction which can be broken up into technical and commercial elements of the system. Some examples of each are listed below:  Technical Elements 

Materials



Material quality



Installation techniques



Traffic

 Commercial Elements 

Contract understanding



Environmental aspects



Political aspects



Legal aspects



Public concerns Typically, construction begins at the lowest elevation of the site, regardless of the project type, and moves upward. By reviewing the geotechnical specifications of the project, information is given about



Existing ground conditions



Required equipment for excavation, grading, and material transportation to and from the site



Properties of materials to be excavated



Dewatering requirements necessary for below-grade work



Shoring requirements for excavation protection



Water quantities for compaction and dust control

7.2. Subbase course construction A subbase course is a layer designed of carefully selected materials that is located between the subgrade and base course of the pavement. The subbase thickness is generally in the range of 4 to 16 inches, and it is designed to withstand the required structural capacity of the pavement section. Common materials used for a highway subbase include gravel, crushed stone, or subgrade soil that is stabilized with cement, fly ash, or lime. Permeable subbase courses are becoming more prevalent because of their ability to drain infiltrating water from the surface. They also prevent subsurface water from reaching the pavement surface. When local material costs are excessively expensively or the material requirements to increase the structural bearing of the sub-base are not readily available, highway engineers can increase the bearing capacity of the underlying soil by mixing in Portland cement, foamed asphalt, or with emerging technologies such as the cross-linking styrene acrylic polymer that increases the California Bearing Ratio of in-situ materials by a factor 4 – 6.

7.3. Base course construction The base course is the region of the pavement section that is located directly under the surface course. If there is a subbase course, the base course is constructed directly about this layer. Otherwise, it is built directly on top of the subgrade. Typical base course thickness ranges from 4 to 6 inches and is governed by underlying layer properties. Heavy loads are continuously applied to pavement surfaces, and the base layer absorbs the majority of these stresses. Generally, the base course is constructed with an untreated crushed aggregate such as crushed stone, slag, or gravel. The base course material will have stability under the construction traffic and good drainage characteristics. The base course materials are often treated with cement, bitumen, calcium chloride, sodium chloride, fly ash, or lime. These treatments provide improved support for heavy loads, frost susceptibility, and serves as a moisture barrier between the base and surface layers.

Fig: - subbase and base course

7.4. Surface course construction There are two most commonly used types of pavement surfaces used in highway construction: hotmix asphalt and Portland cement concrete. These pavement surface courses provide a smooth and safe riding surface, while simultaneously transferring the heavy traffic loads through the various base courses and into the underlying subgrade soils. 7.5. Hot-mix asphalt (HMA) layers Hot-mix asphalt surface courses are referred to as flexible pavements. The Super pave System was developed in the late 1980s and has offered changes to the design approach, mix design, specifications, and quality testing of materials. The construction of an effective, long-lasting asphalt pavement requires an experienced construction crew,

committed to their work quality and equipment control. Construction issues: 

Asphalt mix segregation



Laydown



Compaction



Joints 

A prime coat is low viscosity asphalt that is applied to the base course prior to laying the HMA surface course. This coat bonds loose material, creating a cohesive layer between the base course and asphalt surface.  A tack coat is a low viscosity asphalt emulsion that is used to create a bond between an existing pavement surface and new asphalt overlay. Tack coats are typically applied on adjacent pavements (curbs) to assist the bonding of the HMA and concrete.

7.6. Portland cement concrete (PCC) Portland cement concrete surface courses are referred to as rigid pavements, or concrete pavements. There are three general classifications of

concrete pavements - jointed plain, reinforced, and continuously reinforced.

jointed

Traffic loadings are transferred between sections when larger aggregates in the PCC mix inter-lock together, or through load transfer devices in the transverse joints of the surface. Dowel bars are used as load-transferring devices to efficiently transfer loads across transverse joints while maintaining the joint's horizontal and vertical alignment. Tie-bars are deformed steel bars that are placed along longitudinal joints to hold adjacent pavement sections in plan.

Fig:-Pcc use in highway

7.7. Highway maintenance The overall purpose of highway maintenance is to fix defects and preserve the pavement's structure and serviceability. Defects must be defined, understood, and recorded in order to select an appropriate maintenance plan. Defects differ between flexible and rigid pavements. There are four main objectives of highway maintenance: 

repair of functional pavement defects



extend the functional and structural service life of the pavement



maintain road safety and signage



Keep road reserve in acceptable condition.

Fig:-maintenance of highway

7.8. Project management:Project management involves the organization and structuring of project activities from inception to completion. Activities could be the construction of infrastructure such as highways and bridges or major and minor maintenance activities related to constructing such infrastructure. The entire project and involved activities must be handled in a professional manner and completed within deadlines and budget. In addition, minimizing social and environmental impacts is essential to successful project management.

8. CONCLUSIONS:The main objective of this project was to compare highways design method .we have done an introduction pavement design and some geometric design method .we have done flexible and rigid pavement structures. Road are designed for a certain period of time.There has to be a maintenance of them in order to extend the serviceability life time and to keep the road in the best conditions as possible all the time. Also mention that depending on the country we are situated, there are some points to take into account while designing and maintaining the pavement structure, such as temperature or rainfall. So in some countries roads should have more maintenance or cost much more money when constructingthem in order to build a high quality road.

9. Reference Dr.s.k.khanna,Highway roorkee, India.

Engineering,Nem

Chand

&

bros,

Oglesby C, H, Highway Engineering, john Willy & sons. WOODS, K.B., Highway engineering hand book, McGraw hill book co.inc. Chin, Antony T.H. "Financing Highways." The Handbook of Highway Engineering. Ed. T.W. Fwa. WELLS. G. R., Highway planning techniques-The balance of cost and benefit. Griffin, London. Cheu, R.L. "Highway Geometric Design." The Handbook of Highway Engineering. Ed. T.W. Fwa. Tam, Weng On. "Highway Materials." The Handbook of Highway Engineering. Ed. T.W. Fwa. Mamlouk, Michael S. "Design of Flexible Pavements." The Handbook of Highway Engineering. Ed. T.F. and Wei, Liu. "Design of Rigid Pavements." The Handbook of Highway Engineering. Ed. T.W.