S. P. Bagli, Chief Technology Officer, Strata Geosystems (India) Pvt. Ltd., India

Preamble

The pavement is a structural entity which takes up cyclic stresses from various types of vehicles that are deemed to ply along the selected route over its designated life. The pavement surface is required to take up both vertical and horizontal stresses. These stresses develop strains in the components of the pavement, which, when exceeded beyond certain magnitudes, can cause rutting and fatigue. Horizontal stresses and corresponding strains are also generated by vehicle traction. The quality of the riding surface is a key factor to give comfort to the driver and the passengers and the pavement is designed to cater to these stresses and minimise strains over the designated life.

Schematic Flexible Pavement Crust Section
Figure 1: Schematic flexible pavement crust section (after Jorge Zornberg4)
It is significant that paved roads have been found in the ancient Indus Valley Civilisation settlements of Harappa and Mohenjo Daro, the first human settlement clusters, inhabited around 4000BC. During the early part of the previous century, cities like Bombay had cobblestone paved roads with light traffic including animal carts and human hauled barrows and carts. Ever since, the pavement structure has become more and more high-tech with increase in traffic intensities and a multitude of combinations of axle loads. These pavements fall under two broad categories:

a) Flexible Pavements,
b) Rigid Pavements.

This paper addresses flexible pavements. A schematic of flexible pavement components is shown in Fig. 1.

There is great scope of application of geosynthetics as structural entities in flexible pavements. Flexible pavements reflect deformations of subgrade and from within the layered components to the pavement surface. Flexible pavements carrying higher traffic loads invariably have asphaltic surfaces. Pavements for lighter traffic as in rural areas may be unpaved. Conventionally, these pavements do not incorporate any geosynthetic or any other type of reinforcement.

Conventional Pavement Designs

The principles of design of a flexible pavement are based on stress distributing characteristics of the individual component layers of the pavement and their deformations under the corresponding stresses. Stress is maximum at the pavement surface directly under the wheel and is equal to contact pressure under the wheels. Vertical stresses also induce horizontal tensile stresses. The various layers of the pavement distribute the stress progressively over a larger area in the form of a truncated cone right down to the lowest layer where the load is spread over a larger area. Hence the stresses are greatly reduced. The uppermost layers, which experience maximum vertical stresses as well as horizontal tensile stresses, need to be most resilient with a robust stress-strain relationship. The lower layers take up lesser magnitudes of stress and there is no direct wearing action. Therefore material of the lower layers of a pavement section may be with lower strength and stress-strain characteristics.

Conventionally, the highway designer considers the characteristics of various components of the pavement crust and their respective thicknesses to carry the design traffic over the design life of the structure. With the introduction of geosynthetics, the designer sees advantage. It may either retain the thickness of the pavement crust but increase the life of the structure, or reduce the thickness(es) of the various components of the pavement crust, thereby achieving economic solutions as well as effecting conservation of the environment by using less natural resources, while maintaining the life of the pavement structure.

This section of the article is only available for our subscribers. Please click here to subscribe to a subscription plan to view this part of the article.

Click Here
To Know More or to Contact the Manufacturer
Please let us know your name.
Invalid Input
Please let us know your Designation.
Please let us know your Contact Number.
Please let us know your email address.
Please brief your query.
Our other Value-Added Services:

To receive updates through e-mail on Products, New Technologies & Equipment, please select the Product Category(s) you are interested in and click 'Submit'. This will help you save time plus you will get the best price quotations from many manufacturers, which you can then evaluate and negotiate.

Invalid Input
Invalid Input
Invalid Input
Atasi Das, Assistant Vice President, G R Infraprojects, explains the concept of the Perpetual Pavement in India’s expressway constructions and its practical implementation with due consideration of layers, materials, and thicknesses

Read more ...

Dr. Rakesh Kumar, Senior Principal Scientist & Pankaj Goel, Senior Technical Officer, Rigid Pavements Division,CSIR-Central Road Research Institute (CRRI), New Delhi, give information on the Performance of Curing Compounds in Strengthening

Read more ...

The construction and maintenance of roads with flexible pavements in very cold regions where annual temperatures range between +30oC to -35oC has got its own challenges. The bitumen in the asphalt layer becomes hard at such low temperatures

Read more ...

The Bundelkhand site team achieved yet another feat on 15 Jan 2022 by completing 13 deck slabs of varying types in just 46 days. Therefore, it is a demonstration of exemplary display of overall project executing capabilities

Read more ...

Er. Devjyoti Paul, Project Manager & Er. Harpreet Singh, Chief Project Manager, B&SEC, share the technical and construction features of three bowstring girder ROBs, recently constructed under Package I & III of Purvanchal Expressway in the state of Uttar Pradesh

Read more ...

Use of Extruded Polystyrene Sheets (XPS) in the construction of the Zojila Approach Road has been especially effective as XPS is the most suitable, convenient, and cheaper solution for mitigating frost action on pavements, increasing the life of pavements

Read more ...

The Indian road network is the second largest globally, with a length of around 63.86 lakh km. The outbreak of the virus towards end-FY20 had created panic globally, leading to the temporary suspension of economic activity

Read more ...

Roads and Railways boost awards; tenders up marginally Overall tendering grew 5% YoY during H1FY22 Awarding activity grew at a 2-year CAGR of 22% in H1FY22 Infrastructure credit near all-time highs

Read more ...

There are many challenges being faced by the highway sector such as ensuring availability of construction materials and machinery, timely completion of projects, availability of trained human resources

Read more ...

Practical Recommendations for Construction of Longitudinal Joints in Hot Mix Asphalt (HMA) Pavements Rajib B. Mallick, Ralph White Family Distinguished Professor, Civil and Environmental Engineering, Worcester Polytechnic Institute (WPI), Massachusetts, USA, and Veeraragavan

Read more ...

Plant and Equipment Determine Quality of Road Construction Road Infrastructure projects are time constrained; early completion of project entitles rewards while delays attract penalties. The plants and equipment being used determines the quality of the road

Read more ...

New Road Technologies & Smart Roads The exponential increase in the number of vehicles on roads has led to multiple traffic problems and associated risks, traffic congestions, etc., yet the roads, despite being arteries of modern

Read more ...

Designing roads and highways efficiently with the right materials will help achieve optimum construction cost, lower maintenance, and reduce life cycle costs. Ash from coal-fired thermal power

Read more ...

Rodic Consultants has emerged as a leader in the infrastructure consulting space with state-of-the-art engineering solutions, and a proven track record of timely completion of projects across sectors

Read more ...

Readymade Kandhal Pothole Patching Mix was adopted as Indian Roads Congress (IRC) Standard Specification IRC: 116-2014 for Readymade Bituminous Pothole Patching Mix Using Cut-Back Bitumen. All concerned

Read more ...

The Bundelkhand Expressway is a 296-km long, 4-lane wide (expandable to 6 lanes) access-controlled expressway in the state of Uttar Pradesh. It will connect Gonda village in Chitrakoot district with Agra–Lucknow

Read more ...

This case study briefly discusses the planning, design and construction of Package 3 of the Purvanchal Expressway. Package-3 of the Purvanchal Expressway is a 41.7km long section of the 340.82km long

Read more ...

Since the 1980’s billions of dollars have been invested in developing methods to make pavement design and construction more sustainable through the re-use of existing resources. This includes insitu recycling and

Read more ...

India has the second largest road network in the world, spanning a total of 5.89 million km, transporting 64.5% of all goods in the country. Nearly 90% of India's total passenger traffic uses the road network to commute

Read more ...

India generates nearly 26,000 tonnes of plastic waste every day, making it the 15th biggest plastic polluter globally. Discarded plastic waste litter the country’s roads, rivers and also form huge mounds in garbage

Read more ...

×
Sign-up for Free Subscription
'India Construction Week'
Weekly e-Newsletter on Construction Industry
Get the latest news, product launches, projects announced / awarded, government policies, investments, and expert views.