Latest Technologies and Mechanization for Sustainable Road Construction & Maintenance of Pavements

Anjaneyappa, PhD, MIE, MASCE, Associate Professor, Department of Civil Engineering, RV College of Engineering, Bengaluru

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 will continue for years to come as more road networks need to be designed and developed. Hence, sustainable road construction practices need to be adopted in reconstructing and rehabilitating the pavements to meet the functional and structural requirements of pavements.

The induction of modern plants and equipment is an essential requisite for the production of uniform and high-quality pavements, as utilisation of appropriate plants and equipment for sustainable construction enhances the quality and production.

The stabilization of subgrade, granular sub-base, and base layers using conventional or commercial binders decreases the thickness of pavement layers compared to conventional pavement composition, thereby reducing consumption of soil and crushed aggregates. Similarly, use of reclaimed bituminous materials in bituminous binder layers reduces the consumption of virgin aggregates and binder.

Given below are a few important modern equipment used for the construction of stabilised pavement layers and reclaimed bituminous layers, including equipment used for pavement maintenance:

Stabilization of Subgrade
A Spreader is used to spread the defined quantity of lime or cement binder uniformly over a graded, loose layer of subgrade. The quantity of lime/cement binder depends on the degree of stabilization/strength desired. The Stabiliser machine mixes the soil and binder at the optimum moisture content of the soil. The stabiliser machine helps in uniform mixing and controls the depth of mixing. The pad-foot roller is used to compact the soil layer mixed with binder. The pad-foot roller helps in achieving higher density across the depth of the layer.

A Motor Grader is used to level the layer compacted by the pad-foot roller. The layer is allowed to cure for few days while light sprinkling of water is carried out. Pulverization, uniform spreading of binder, mixing, and compaction are important factors influencing the quality, which are better controlled by the spreader, stabiliser, and pad-foot roller. The same procedure is followed for the stabilisation of the subbase and base layers. Process of stabilisation of subgrade is presented in Figure1.

Latest Technologies and Mechanization for Sustainable Road Construction & Maintenance of PavementsFigure 1: Stabilization of Subgrade
Picture courtesy: Wirtgen Group

Rehabilitation of the bituminous layer
Sustainable construction practices can be adopted for rehabilitation of distressed bituminous layers. A spreader is used to spread the virgin aggregate mix of known gradation and quantity on the distressed bituminous layer. A Stabilizer machine is used to mix the virgin aggregates, foamed bitumen/emulsion and reclaimed bituminous material in situ. A grader is used to get the required cross and longitudinal profile. A vibratory roller is used for compacting the graded layer. A grader is again used to level the compacted surface and is required only when pad-foot roller is used (Smooth drum vibratory can also be used to compact the graded layer instead of pad-foot roller). A smooth wheel dual drum wheel roller is used for final rolling and also for removing roller marks.

Uniform spreading of aggregates, mixing of aggregates, bitumen and reclaimed bituminous material, and compaction greatly influence the quality of pavement, which is better controlled using these equipment. Rehabilitation of typical distressed bituminous pavement is shown in Figure 2.

Latest Technologies and Mechanization for Sustainable Road Construction & Maintenance of PavementsFigure 2: Rehabilitation of distressed bituminous pavement

Hot mix plant with a RAP bin
Construction of bituminous pavement layers using reclaimed asphalt materials (RAP) is yet to start in the country. Making use of milled bituminous material is important towards sustainable pavement construction practices. A RAP bin attachment can be made compulsory to all the hot mix plants used for major projects in the country. RAP bins are not purchased while procuring hot mix plants as they are not used. Use of RAP in bituminous layers must start and should become a conventional practice in the future. RAP bin attachment to hot mix plant is shown in figure 3.

Milling machine
Reclaiming of bituminous materials from the bituminous pavement through milling operations is an important activity in sustainable bituminous pavement construction practice. A milling machine mills the existing pavement to the required depth without damaging the bottom layer. The milled materials are further stockpiled for use in bituminous mixes for binder pavement layers. Milling is a necessary and a better option for any cracked pavement layer which does not warrant rehabilitation or reconstruction. Typical milling of bituminous pavement is shown in Figure 4.

Latest Technologies and Mechanization for Sustainable Road Construction & Maintenance of Pavements

Micro surfacing machine
Maintenance is important for pavement to serve the road users at desired level during its design life. Micro surfacing is slowly gaining importance for preventive and maintenance of bituminous pavements in the country. Single setup is where preparation of bituminous mix using emulsion and its spreading is carried out. No rolling is required and traffic is allowed after layer sets which is generally about an hour. Micro surfacing is shown in Figure 5.

Latest Technologies and Mechanization for Sustainable Road Construction & Maintenance of PavementsFigure 5: Micro surfacing

Aggregate Spreader
Aggregate spreader can be used effectively for maintenance activities such as surface dressing. Graded aggregates are spread evenly across the width of the pavement on an emulsion coated surface. These machines could be more useful in maintenance activities and yet to be seen in the country. A typical aggregate spreader is shown in Figure 6.

Latest Technologies and Mechanization for Sustainable Road Construction & Maintenance of PavementsFigure 6. Aggregate spreader
(Source: https://roadresource.org/treatment_resources/chip_seal?page=about_process)

Why are sustainable practices not being followed?
Except for R&D and demonstration projects, sustainable practices like stabilisation techniques and use of RAP in bituminous layers are not being practiced. The reasons for these may include resistance to change, fear of failure, intensive supervision during construction for these types of projects, additional approvals and consequential delays, and lack of needed support from clients and consultants.
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 ...

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 ...

×
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.
Click here to subscribe.