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Flexible Pavements Division

Divisional Profile

Majority of Indian road network being of flexible pavements, the division acquires a significant position in meeting the demands of the industry for R&D capped associated activities.  In this endeavour the division recognises its thrust area with design, construction, maintenance, failure investigations and serviceability  management of roads of all categories and runways, in different topographical conditions and terrains.  The division also involves in exploration of optimised usage of industrial and other wastes.  One of the prime areas of activity is experimenting with technologies that are sustainable and environment friendly. 

The requisites are met by the highly competent and experienced team composing personnel by multi-disciplinary backgrounds.  The division is also well equipped with latest state-of-the-art facilities including soft tools.  With its strong backup capability, the division provides technical and consultancy services to user organisations, to their utmost satisfaction. The division also actively and continuously thrives to contribute to the confidence building and educating programmes, within and outside the institute through various regular and customised training sessions.

Areas of R&D/Consultancy/Core Activities

Areas of R&D

  • Design of Flexible & Composite Pavements for Roads and Airfields
  • Additive for Beneficiation of Soil (Inorganic Additives, Organic Additive, Nano Materials, Bio- enzymes, Geopolymers, Biopolymers)
  • Mineral Aggregates: Characterization and Beneficiation
  • Industrial Wastes and Artificial Aggregates:Use in Bituminous mixes
  • Organic Binders (Bitumen, Rubber & Polymer Modified Binders, Cut Back Bitumen and Emulsion)
  • Additives for Bituminous Binders (Anti-stripping Agents, Antioxidants, Polymers and Warm Mix Additives)
  • Construction and Maintenance Technologies (Recycling, Micro Surfacing Slurry Sealing and Ready to Use Patching Mixes)
  • Cold Mix and Warm Mix Technologies for Construction and Maintenance

Consultancy/Core Activities

  • Design of Flexible and Composite Pavement and Overlays for Roads, Airfields and Parking Areas
  • Investigations for Failure of the Flexible & Composite Pavement and Remedial Measure
  • Evaluation of Pavement Materials for Construction and Maintenance of Flexible & Composite Pavement
  • Feasibility Studies of Use of Waste and Marginal Materials
  • Supervision of Construction and Quality Control of Flexible Pavement
  • Setting up of Laboratories & Industrial Units for Bitumen, PMB and Emulsion
  • Customized Training Programs in the area of Engineering Materials, Design, Construction and Maintenance
  • Workshop of New Technologies
  • Preparation of New Standards and Specifications
  • Evaluation of Design and Specifications by Accelerated Pavement Testing Facilities
  • Pilot Studies of New Technologies and Materials
  • Design of Airfield Pavements
  • Design, Construction and Maintenance of Rural Roads

Equipment, Facilities/Software in the Division

  • Accelerated Pavement Testing Facility: This is a National Facility. This is used for faster evaluation of materials, design and specifications.
  • Wheel Tracking System: This equipment is used for evaluation of the rutting in bituminous layers at different temperature.
  • Creep Testing System: This equipment is used to investigate creep behavior and also for the determination of stiffness modulus of bituminous mixes.
  • Beam Fatigue Testing System: This equipment is used for study of the Fatigue Behavior of Bituminous Mixes.
  • Brook-Field Viscometer: This equipment is used for measurement of the viscosity of bituminous binders including modified binders.
  • Capillary Viscometer: This equipment is used for measuring of the absolute viscosity of the bituminous binders.
  • Pilot Plant for Manufacture of Modified Bitumen and Emulsions: This equipment is used for production of the modified bitumen, modified emulsions and different grades of conventional bitumen emulsions.
  • Equipments for Design of Micro-surfacing: A view of various equipments used for design of micro-surfacing
  • Gyratory Compactor: This equipment is used for preparation of the Marshal specimens for various testing purposes.
  • Bitumen Testing Equipments: View of penetration testing, softening point and durability testing
  • Automatic Marshal Testing Machine.
  • Bending Beam Rheometer.
  • Dynamic Sheer Rheometer
  • Direct Tension Tester
  • Presure Aging Vessel
  • Presser Ageing Vessel for long term ageing of bitumen
  • Apparatus for Zeta Potential
  • Binder drainage test and permeability test for persons concrete

Systems and Technologies Developed by the Division

  • Polybit A and Polybit B. Technology
  • Elastomeric Bitumen Technology
  • Improved Crumb Rubber Modified Bitumen
  • Ready to Use Patching Mixes
  • Cold Mix Technology
  • Repair of Cracks on Bridge Deck Wearing Coats



Title: Up gradation and Demonstration of Pothole Repair Machine

Potholes are one of the most visible and annoying forms of bituminous pavement distresses from the view point of a road user. Potholes have always been a problem for highway maintenance agencies because their treatment is complex, costly and time-consuming. The problem aggravates much during the rainy season, when pothole repair becomes more difficult because of adverse weather conditions and the large number of potholes that seem to develop at faster rate.

To effectively address the cumbersome time consuming act for repair of potholes, CSIR-CRRI has developed a laboratory model of compact and low cost Pothole Repair Machine indigenously. Up gradation, demonstration and field performance evaluation of machine is further required to strengthen the concepts to reach the stakeholders.

Title: Use of Steel Slag in Road Construction

  • Disposal of slag is a major concern for steel industries as it is considered as a waste material

  • Disposal of metallurgical and metal-processing waste as landfills are particularly hazardous for the environment

  • Processed steel slag aggregate exhibit great potential as a replacement for natural aggregates inroad construction Potential application of steel slag in bituminous pavement is explored as 100% replacement of natural aggregate

  • Methodology to crush the steel slag in suitable aggregate sizes are provided to steel industries

  • Technology to reduce the free lime content in steel slag aggregate to prevent volumetric change in aggregate was defined

Method and process is to be developed to utilize processed steel slag aggregate in bituminous granular layers of flexible pavement were provide to road and steel industries.

 Title: Design and Development of CGBM Construction Technology

  • Mix design methodology for the Cementitious Grout Bituminous Mix CGBM.
  • Cementitious grout material for use in Cement grout bituminous mix.An Agency, M/s International Combustion (India) Limited has been associated for development of grout for the most suited requirement.
  • Pavement performance monitoring to evolve guidelines and specifications based on two trial section laid in surat.



Title: Low Energy Mixes for High End Bituminous Layers

Until now, cold bituminous mixes have not been considered at par/equivalent to hot bituminous mixtures. These have been used/ specified for only thin bituminous surfacing or maintenance mixes. There are three main concerns with cold mixes.

  • High air void content of the compacted mixtures;
  • Lower early life strength (caused mainly by the trapped water);
  • The long curing times (evaporation of water/volatiles content and setting of the emulsion) required to achieve stipulated performance; and
  • Possibility of lump formation due to high fines content in mixes like DBM & BC.

The broad objective of this study is to investigate the volumetric properties and mechanical performance of the low energy mixes, the effect of storage time on loose cold mixes, and a realistic evaluation of the rate of strength gain of low energy mixes cured outdoors, in order to seek inferences to formulate low energy mixes fit to be used in surfacing/thicker courses.

Title: Design/Development of prefabricated plastic slabs/panels made from waste plastic for road construction

Need of the study: Bitumen and cement are the main binding agents for construction of flexible and rigid pavement respectively. Each type of pavement has some advantages and disadvantages. Cracking, raveling, potholes, shoving, rut, edge break, etc. are some of the common pavement distress found in present roads. Beside binding agent, aggregate and filler is required in large quantity for construction of roads. With a ban on quarries in various states, availability of construction materials is a challenge for road construction industry. Also strengthening/repair/rehabilitation of roads requires large amount of aggregates and binding material. Beside this blockage of roads during this period leads to traffic jam and inconvenience to commuters. Considering all these problems associated with present roads, there is need to develop and design roads with such materials which can answer all these issues. With advancement in material science4 and introduction of nano-materials, some polymer/nano-material composites are used in different industries which satisfactorily taking the external forces/loads and other environment conditions without much distress. Finally these materials last up to 30 years life cycle in sustainable manner. To have roads free of all the above said distresses, there is a need to introduce new range of material for road construction in place of conventional materials such aggregate, bitumen and cement. The road designed and constructed with new materials and design methodology for road construction so that roads can be designed in more sustainable manners.

In this study an attempt will be made to use this plastic as base material. Further properties will be improved through R&D to develop engineered plastic out of this base material by adding some additives, etc. and finally engineered plastic will be used for production of slab/panel for road construction applications and other value added products in road system.