Refer to the flexible pavement joint and crack sealing section in chapter a of this manual, as this work is similar whether the pavement is flexible or rigid. Flexible and rigid pavement are designed for similar soil and traffic conditions using appropriately related, different methods and. Different pavement types use different types of joints and reinforcement to control the forces acting on the concrete pavement. Flexible pavements see figure, left have base courses of broken stone pieces either compacted into place in the style of mcadam or glued together with bitumen to form asphalt. Critical condition of stress in the rigid pavement is the maximum flexural stress occurring in the slab due to wheel load and the temperature changes. Christos drakos university of florida topic 10 aashto rigid pavement design 1. This is an introduction to rigid pavement design for engineers. Compared to flexible pavement, rigid pavements are placed either directly on the prepared subgrade or on a single layer of granular or stabilized material. Key words flexible pavement, rigid pavement, lifecycle cost. The project titled evaluation of flexible and rigid pavements construction in bangladesh, submitted by mohammad arifuzzaman bhuyan, roll no. Without joints, most concrete pavements would be riddled with cracks within one or two years after placement. The plain cement concrete slabs are expected to take up about 45kgcm2 flexural stress. Appendix e computer aided design for flexible road pavements rigid road pavements.
Flexible pavements are those pavements which reflect the deformation of subgrade and the subsequent layers to the surface. The loads will distribute to natural soil layer through different layers of rigid pavement. Probabilistic design of flexible and rigid pavements using aashto equations annan a. Rigid pavement is laid in slabs with steel reinforcement. The rigid pavements are made of cement concrete either plan, reinforced or prestressed concrete. Flexible pavements are preferred over cement concrete roads because of their certain advantages like they can be strengthened and improved in stages with the. The lifespan of the design of flexible pavement is 15 years whereas, in case of rigid pavement, the time period of lifespan is 30 years double to flexible pavement. January 2009 implementation memo rigid pavement design. Section 5 rigid pavement construction standard specification for urban infrastructure works 55 edition 1, revision 0 september 2002 testing a testing authority shall be employed by the contractor to carry out all testing.
Design of rigid and flexible pavements by various methods. One major design consideration of rigid pavements is reducing fatigue failure due to the repeated stresses of traffic. Before we differentiate between flexible pavements and rigid. However, some recent research studies indicate that the performance predicted by this methodology shows a low sensitivity to the properties of underlying layers and does not always reflect the extent of the anticipated effect, so the procedures contained in the. April 2004 has been accepted as satisfactory in partial fulfilment of.
Standard specification for urban infrastructure works 47 edition 1, revision 02 oct 2010. Contrary to flexible pavements, rigid pavements were designed from the beginning using analytical solutions. The service life of a flexible pavement is typically designed in the range of 20 to 30 years. In rigid pavement the stresses are not transferred from the grain to grain to the lower layers. Comparative studies of flexible and rigid pavement design. The last century has seen an intensive process of urbanization in rural as well as metro cities. Engineers are cautioned that much of pavement design is governed by codes, specifications and practices of public agencies. For critical design, a combination of load stress, frictional stress and warping stress is considered. The rigid pavements are made of portland cement concrete either plain, reinforced or prestressed concrete. The field performances of texas pp sections are still in good condition to date, with no major structural distresses.
Design of rigid pavements is based on westergaards analysis, where modulus of subgrade reaction, radius of relative stiffness, radius of wheel load distribution are used. A pavement or road is a structure consisting of superimposed layers of processed materials above the natural soil subgrade, whose primary function is to distribute the applied vehicle loads to the subgrade. Date 2019 rigid pavement design manual rpdm 110118 2018 rigid pavement design manual rpdm summary of changes to 2018 rpdm. The design procedures provided will include the determination of the total pavement thickness as well as the.
Rigid and flexible pavement designs in construction international. Flexible pavement a rigid pavement has a very high stiffness and distributes loads over a relatively wide area of subgrade a major portion of the structural capacity is contributed by the slab itself. Roadway design florida department of transportation home. Thus the strength of subgrade primarily influences the thickness of the flexible pavement. Rigid pavements must be designed to endure frequently repeated traffic loadings. For vehicular use are generally divided into two main categories i rigid pavements have a high compressive strength, which tends to distribute the load over a relatively wide area of soil. Rigid pavement analysis and design fhwa us department of. Flexible pavement has very low modulus of elasticity less strength. What is the difference between rigid pavement and flexible. Shoulder backing pavement tech notes pdf safety edge pdf california highway design manual. Layers system aashto design method asphalt institute ai portland cement association pca studding international flexible and rigid pavement design methods.
Types of pavements flexible pavement rigid pavement. Mndot flexible pavement design, rvalue method excel, 0. There are two types of pavements based on design considerations i. Rigid pavement and flexible pavement are the two types of road pavement design methods. The pavements can be classified based on the structural performance into two, flexible pavements and rigid pavements. Flexible pavements carries such name, because the entire pavement has the elastic deflection under load. In flexible pavements, underlying layers play very important role. Rigid pavements support loads through rigidity and high modulus of elasticity of concrete slab. Albalbissr this paper applies statistical and probabilistic methods to the design of pavements, using the existing aashto equations. Flexible pavement differ from rigid pavement in terms of load distribution. Sustainable perpetual asphalt pavements and comparative. The pavement surface should be durable and it can withstand the load acting from the wheel tyres.
Over 200 test sections jpcp 15spacing and jrpc 40spacing range of slab thickness. Even though all pavement design methods, in particular the aashto design, consider the effect of factors such as. Advantage and disadvantage of flexible and rigid pavement. Joints in rigid pavement transportation engineering. What is the difference between flexible and rigid pavement. Water, ice, salt and loads would eventually cause differential settlement and premature pavement failures. A typical cross section of the rigid pavement is shown in figure 3. This paper presents the results of pavement plateau dimensioning, designed for traffic of heavy vehicles dump trucks exclusively with a. In the construction industry, designing of pavement is one of the most challenging tasks. Types of pavement flexible pavements and rigid pavements. The pavement structure consists of the bitumen bound. However, because it is not always practical to remove and replace rigid pavement for every overlay, the following guidance should be followed regarding tapers for rigid pavement. The following points help you to better understand the difference between the two type of road pavements.
This paper compares for india the properties and costs of a cement concrete rigid pavement with those of a flexible pavement, composed of granular material, waterbound macadam, and a bituminous course. Pavement design note pdf download lecturenotes for free. This study is a survey to evaluate the flexible pavement conditions to determine and specify the types of the failures in the pavement for the selected highway. Rigid vs flexible pavement civil engineering pavement.
Moreover, temperature variations are sensitive in rigid pavements inducing heavy stresses. Types of pavement flexible and rigid pavement there are two types of pavements based on design considerations i. Director, csircentral road research institute, delhi two types of pavements are laid in india rigid pavement and flexible pavement. A project description form pdf was prepared for state agencies interested in. Flexible pavement s load carrying capacity is dependent on the layers. One of the main factors affecting the destruction of concrete is shrinkage and cracks. Difference between flexible and rigid pavement properties.
Modulus of elasticity of rigid pavement is very high, because of high strength concrete and more load bearing capacity of the pavement itself. The high flexural strength is predominant and the subgrade strength does not have much importance as in case of flexible pavement. The performance of flexible and rigid pavements is known to be closely related to properties of the base, subbase, andor subgrade. Concretes rigid design reduces the pavement s deflection and corresponding fuel consumption. Grinding rigid pavement to create a taper is not recommended because it can shorten the life of the rigid pavement. This pressure deformation characteristics of rigid pavement lead westergaard to the define the term radius of relative stiffness in cm is given by the equation. We know that rigid pavement is constructed using reinforced cement concrete. Generally this type of pavement requires some sort of maintenance or restoration every 10 to 15 years. April 2004 has been accepted as satisfactory in partial fulfilment of requirement of the requirement for the.
Introduction to flexible pavement design ced engineering. The above same scenario is also applicable while we construct rigid pavements. This is expected to save significant quantities of cement. The major purpose for applying such methods was to. Pdf a comparative study on rigid and flexible pavement. Maintenance and rehabilitation is to be properly done to prevent the distresses in rigid pavement.
Antonis michael frederick university notes courtesy of dr. To limit this, we know that we will provide some joints in buildings construction and others. It is not intended as definitive treatise, and it does not encompass the design of flexible pavements. In flexible pavements load distribution is primarily based on layered system. Introduction empirical design based on the aasho road test. Recommendation of best design methods and construction practices. This paper presents the results of pavement plateau dimensioning, designed for traffic of heavy vehicles dump trucks exclusively with a weight of 2,350 kn, ie.
Conclusion rigid pavement distress is a serious issue all over the world, the distresses causes some serious problems at wide range. While, in case of rigid pavements most of the load carries by slab itself and slight load goes to the underlying strata. It is not intended as definitive treatise, and it does not encompass the design of rigid pavements. It is the responsibility of the pavement design engineer to insure that the designs produced conform. Design of rigid pavement the soil sub grade is a layer of natural soil prepared to receive the other layers of the pavement the loads on the pavements are ultimately taken by the soil sub grade and dispersed to the earth mass below. In this project we want to compare between the flexible and rigid pavement design methods. Design, pavement, flexible and rigid, heavy vehicles 1. The typical designed service life of a rigid pavement is between 30 and 40 years, lasting about twice as long as a flexible pavement. Types of pavements flexible pavements and rigid pavements. Subsealing or jacking, also known as mudjacking, is used to fill voids in the base under concrete.
In flexible pavements, wheel loads are transferred by graintograin contact of the aggregate through the granular structure. Prevention of rigid pavement distress is a challenge to the engineers. Comparison between flexible pavement and rigid pavement in. The functional requirement of highway pavements are. Pavement joints are vital to control pavement cracking and pavement movement. Flexible pavement and rigid pavement have good riding quality. This has led for a need of rapid construction of roads and transportation infrastructure.
Probabilistic design of flexible and rigid pavements using. The technique of providing cement concrete overlays on bituminous pavements is known as whitetopping. Difference between flexible pavement and rigid pavement. The pavement structure should be able to provide a surface. Flexible pavement dib 86 has been incorporated into july 1, 2008 edition of hdm and. Difference between flexible and rigid pavements is based on the manner in which the loads are distributed to the subgrade. Many chapters in the california highway design manual hdm provide information relevant to pavement design standards. The fact that the subgrade cbr or mr can be convert to k and easls into ald makes it possible to design the two types of pavements. Comparison between flexible pavement and rigid pavement in highway construction. Reem salim nasser alaamri 1, rafeeq ameen kat tiparuthi 2, alaa moosa koya 3. Nov 05, 2016 rigid pavementrigid pavement 20 deflection is very small hence the name rigid pavement.
Heavy vehicles cause greater deflection on flexible pavements rather than on rigid pavements. Rigid pavements have sufficient flexural strength to transmit the wheel load stresses to a wider area below. Rigid and flexible pavements 1972 aashto interim guide for the design of pavement structures 1972 1981 revised chapter iii on portland cement concrete pavement design 1986 guide for the design of pavement structures 1993 revised overlay design procedures 1998 revised portland cement concrete pavement design. Engineers must always determine the requirements of the. Different types of joints are required like expansion and contraction. The flexible pavement is taken to be a base course and its modulus of subgrade reaction is determined. Difference between flexible and rigid pavements is based on the manner in which the loads. It provides a guide for determining new pavement structures similar to the ones shown in figure 11. Base material shall be manufactured from hard, durable stone or recycled building materials free of clay lumps, organic matter and other deleterious substances.
When the pavement deflects or moves, it absorbs a portion of the vehicle energy that otherwise would be available to propel the vehicle forward. Flexible, usually asphalt, is laid with no reinforcement or with a specialized fabric reinforcement that permits limited flow or re positioning of the roadbed under ground changes. This report will be of interest to engineers involved in rigid pavement design and anal ys i s. Flexible pavement are preferred over cement concrete roads as they have a great advantage that these can be strengthened. The demand for better roads and services required researchers. Introduction to rigid pavement design ced engineering. The flexible pavement, having less flexural strength, acts like a flexible sheet e.
The pavement design is also one major factor, with flexible pavements reliant on subgrade strength and rigid pavement dependent on the flexural strength of concrete. Comparative studies of flexible and rigid pavement design methods. In simple terms, a flexible pavement can be defined as a pavement layer comprising of a mixture of aggregates and bitumen, heated and mixed properly and then laid and compacted on a bed of granular layer. Rigid pavements can have reinforcing steel, which is generally used to handle thermal stresses to reduce or eliminate joints and maintain tight crack widths. A rigid pavement used to strengthen an existing flexible. You created this pdf from an application that is not licensed to print to.
The strength of a flexible pavement is a result of building up thick layers and thereby distributing the load over the sub grade. Apr 27, 2015 flexible pavements are those which are surfaced with bituminous or asphalt materials. The compostion and structure of rigid pavement tells us about the function of each layer of rigid pavement. A thin layer of flexible pavement over rigid pavement is an ideal pavement with most desirable characteristics. Flexible or curved forms of proper radius shall be used on curves of 150feet 45 m radius or less and shall be an approved design.
Its flexible since the total pavement structure bends or deflects due to the traffic loads. Required thicknesses of each layer of a flexible pavement vary widely depending on the materials used, magnitude, number of repetitions of traffic loads, environmental conditions, and the desired service life of the pavement. Engineers are cautioned that much of pavement design is governed by codes, specifications and practices of. This design manual addresses methods to properly develop a rehabilitation project, pavement milling, and the computations necessary for the pavement design process. This is an introduction to flexible pavement design for engineers. Download pdf of pavement design note civil engineering offline reading, offline notes, free download in app, engineering class handwritten notes, exam notes, previous year questions, pdf free download. Subsealing or jacking, also known as mudjacking, is used to. Existing pavement to be overlaid with rigid pavement is composed of an all bituminous or flexible overlay on a rigid base pavement. A pavement constructed on an existing base pavement to increase loadcarrying capacity or correct a surface defect. Applications to rigid pavements were made by kher and darter 6, 7. Pdf evaluation of flexible pavement failuresa case study. Over 200 test sections jpcp 15 spacing and jrpc 40 spacing.