Dr. Ambika Behl, Dr. G. Bharath, Dr. Siksha Kar, Central Road Research Institute, New Delhi

Construction of Sustainable Pavements Through Recycling

Increased connectivity and improved road infrastructure developed in the country in the recent past has resulted in significant increase in the growth of traffic in terms of the number of vehicles and axle loads. However, the increased construction activities have resulted in an increased demand of materials and thereby allowing depletion of naturally occurring materials like stone aggregates. This has made the concerned engineers to explore the alternate methods including re-use of materials from existing pavements. Beneficial utilization of recycled materials can result in an important opportunity to save the mining and use of virgin materials, preserve energy, and save landfill space.

The main components of asphalt mixture are asphalt binder and aggregate, which have the potential to be replaced by recycled materials. The largest portion of pavement in terms of mass and volume are aggregates. The unit price of the aggregates is comparatively low with relatively low environmental impact on production. Correspondingly, because aggregate is exercised in large quantities, is non-renewable, and incapable to mine near its point of use, it can play a vital role in pavement sustainability.

Milling of distressed pavements for their complete or partial use is an accepted norm now to save fresh aggregates and bitumen. Recycling or reuse of pavement material is a very simple but powerful concept. In a time when highway professionals determine pavement rehabilitation techniques based on cost, performance, and environmental sustainability, in-situ recycling processes offer the best alternative to optimize these benefits. With strict attention paid to pre-engineering, mix design formulation, construction, and quality control, pavements constructed using these techniques offer the ability to decrease life-cycle costs and the environmental impact.

The conventional method of providing bituminous surfacing on flexible pavements requires significant amount of materials and energy. Therefore, in order to reduce consumption of fuel and aggregates, pavement recycling technology may be adopted for Indian roads (Reddy et al., 2013). Also, there is a problem of the scarcity of aggregates, which forces truck delivery of materials from long distance. The use of diesel for running these trucks contributes to emission of pollutants such as particulate matter, nitrogen oxides, carbon dioxides and sulphur dioxides. Many of the diesel engine emissions have been identified as carcinogenic, and harmful to the human health, even at occupational and environmental levels of exposure. For a lead of 200 km (which is common in north India), requires 18 million liters of diesel in transportation alone (Mallick and Veeraraghvan, 2010).

Based on the process adopted in recycling the asphalt mix, it can be broadly classified as central plant recycling and in-situ recycling. If the RAP (recycled asphalt pavement) is modified at a plant, away from construction site then the process is known as central plant recycling. In-situ recycling process the RAP modified in place, where from it is available. Further, the RAP could be heated to condition it. If heat is applied, then the process is known as hot mix recycling. In case of cold mix recycling, old materials are conditioned using recycling agent (like, low viscosity emulsion or foamed bitumen) without application of heat.

CSIR-Central Road Research Institute (CSIR-CRRI) has recommended recycling of pavement in several projects of maintenance, rehabilitation and up gradation of roads. This article presents the case study of rehabilitation and up grading of two road sections in India, Ranchi Ring Road using hot in place recycling (HIPR) and NH-31, using cold in place recycling (CIPR).

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.

Rapid growth in industrial development and economy in last two decades has demanded upgradation of the existing road network in the country. Though there is a huge road network in the country, it is still inadequate to meet accessibility and mobility requirements

Read more ...

Namrata Bichewar, Regional Manager - Maharashtra, Gabion Technologies India Pvt Ltd, discusses the company’s contribution in constructing green highways using Bio-Engineering Erosion Control methods and solutions. The government plans to construct 26 green expressways

Read more ...

A Stone Matrix Asphalt (SMA) pavement laid at Parimal Underpass in Ahmedabad Municipal Corporation has completed 7 years. The underpass, which used to get submerged under almost 2m depth of water due to waterlogging in the monsoons every year

Read more ...

Dr. Abhishek Mittal, Principal Scientist, CSIR-CRRI New Delhi, discusses the effects of changes in temperature due to climate change on pavements with respect to their material, design, construction, and maintenance. A long-term shift in temperature and weather

Read more ...

Massive road development work for huge road network of the country’s national assets is essential for overall development of the country. However, major road development projects consume a huge quantity of soil and crushed aggregates. The consumption of these materials

Read more ...

Following the launch of AEW’s road repair machine ‘Dr. Road’ by Shri Nitin Gadkari, Minister for Road Transport & Highways, Shatish Panchal, Director, AEW Group, informs that the company is geared up to promote the machine to State PWDs and CPWDs

Read more ...

Evaluating the Quality of Asphalt Binders and Plant Produced Asphalt Mixes through Recovered Asphalt Testing and other Mix Properties, Amma Wakefield, MASc, PEng Canadian Regional Engineer Asphalt Institute, Paving-grade asphalt binders are specified based

Read more ...

The Global Road Construction & Safety Conference 2022 will be held on 30th November 2022, at Hotel Taj Palace, New Delhi, in collaboration with CSIR- CRRI, Bitumen India Forum (BIF), National Highways Builders Federation (NHBF)

Read more ...

The road construction industry in India is undergoing a paradigm shift: strong demand, higher investments, and the emergence of newer and more innovative technologies is giving a renewed focus on sustainable developments. These technologies include

Read more ...

Subgrade makes the formation level of the road crust. The material specifications of subgrade material are therefore more demanding than the soil used in general fill or embankment. In some construction projects, it becomes difficult to get the required subgrade

Read more ...

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 ...