Climate Resiliency of Roads in the Clouds

By: Philippine Resources March 18, 2024

By Zeevik Halber

Editor’s note: Zeevik Halber is the CEO of AnyWay Solutions, a company with a longstanding presence in Papua New Guinea and after a few years of exploring is now looking to bring its climate resilient designs and solutions to the Philippines.

Papua New Guinea (PNG) is a land of mystery and splendor. Its untouched wilderness, breathtaking landscapes, diverse cultures, tropical jungles, and majestic high-altitude mountains make it one of the most unique countries in the world.

One of the main roads in the country, The Highland Highways, forms the central backbone of the nation’s road network. It begins at the main port city of Lae in Morobe Province, which runs north-easterly towards Madang Province, branches off to the east well before Madang and heads far inland to the Southern Highlands. Even though it serves as the main access road, most of the highway's length is no more than a two-lane single carriageway, connecting a large portion of the country's population and leading to some of its most vital mining projects.

The road was initially constructed in the 1950s and has since undergone several rehabilitation and maintenance upgrades. Due to the progressive increase in traffic, especially heavy vehicles, the Government of PNG initiated an ambitious upgrade and rehabilitation program with the support of the Asian Development Bank (ADB) called the Sustainable Highlands Highway Investment Program (SHHIP). Through the SHHIP, significant portions of the Highlands Highway were rehabilitated, including drainage and water management elements, as well as the road pavement itself.

Through the Department of Works and Highways (DOWH), the Government of PNG set a goal to enhance the climate resiliency of its road network by implementing an advanced engineering approach, including in-place recycling through stabilization. By implementing this approach, the sub-standard materials of the existing roads’ pavement structures would be recycled, processed, and stabilized. The superior strength of pavements achieved through implementing this approach significantly enhances climate resiliency.

In addition to strengthening the pavement structures, drainage and water management elements would be upgraded and rebuilt to withstand the climatic events that have become more frequent in the region. In recent years, the DOWH has also embarked upon extensive rehabilitation work on existing roads in the country's main cities, including the ones connecting them. This is over and above the many new roads being designed and constructed to support the rapid growth in the country.

Of the few alternative rehabilitation solutions that were considered, the approach AnyWay Solutions (AnyWay) offered was to enhance climate resiliency using cold in-place recycling through stabilization. Given the lack of suitable natural pavement materials near many of the roads throughout the country, the solution was preferred and selected with thorough research conducted by the DOWH.

Rehabilitation of the Highlands Highway started in late 2010 with the upgrading of the 60-km branch road linking Wabag town and the Western Highlands province's capital, Hagen. The mountainous environment and associated extreme climatic and topographical conditions pose challenges to getting to and from the relevant project sites and overcoming operational difficulties related to the terrain in which these project areas are located.

AnyWay has specialized in providing climate resiliency engineering designs and solutions for transport infrastructure for more than two decades, and has worked with the DOWH in developing specific engineering designs and solutions that fit the special conditions of PNG. AnyWay was consulted and has provided an innovative approach to rehabilitating and upgrading many other road projects in PNG, including the Highlands Highway.

To assist the DOWH in achieving its ambitious climate resiliency goal, AnyWay’s main approach has been to address pressing issues, such as the lengthy time it takes to construct roads in this region, the lack of readily available quality road-building materials, and the country's unique natural environment.

AnyWay’s approach to enhancing the climate resiliency of transport infrastructure projects has always been based on localizing the solutions. Thus, AnyWay sent its team of experts to work with the DOWH engineers to evaluate the problem areas, perform geotechnical investigations, provide appropriate pavement designs, and oversee local contractors' rehabilitation and upgrading works.

Through the joint work, AnyWay’s experts shared the wealth of experience they have gained over many years of working on such projects with the various stakeholders, engineers, contractors, supervisors, and local communities. Like in many roads in PNG, the existing pavement structure of the highway has, in most cases, been constructed mainly with locally available alluvial materials that have been identified as being of substandard quality and one of the principal causes of the observed premature distress, leading to the disintegration of the road pavement.

Modifying the rounded aggregate used in the initial construction of the road’s pavement layers was essential to obtain the desired angularity and resultant interlock of the coarse fraction to enhance the strength of the base layer of the road pavement. This element is critical for improving the climate resiliency of roads.

For this to be achieved economically, a recycling approach was taken with a road recycler employed in the construction process. This machine can mill the upper pavement layers, incorporating the bituminous wearing course in areas where the road has been paved and breaking down the rounded coarse aggregate fraction to more angular particles to ensure better resistance to repetitive loading. An added benefit of the recycler is that its penetration depth can be readily adjusted and accurately controlled to produce a new uniform, well-mixed base course material. The fact that this process is performed in-situ reduces traffic congestion and major earthworks along the rehabilitated stretches.

As specialists in climate resilience for transport infrastructure, AnyWay have developed various technologies and solutions that enable the use of such techniques in scenarios that were previously not possible. These solutions are designed to expand the scope of climate resiliency and make it accessible in a wider range of circumstances.

One of these technologies and solutions is a cementitious binder called AnyWay’s Natural Soil Stabilizer. Subsequent stabilization of the processed layers with an ANSS, also using the recycler, has been repeatedly proven to be an effective solution for rehabilitation with a very successful result. The sections of this highway and many roads being rehabilitated since that have been completed using this method are performing to the required standard and, in some cases, exceed expectations. The resiliency of these roads is undoubted, as they withstand the extreme climate events imposed on the region over more than a decade.

Many roads throughout PNG have since been rehabilitated utilizing the rehabilitation and upgrading approach presented by AnyWay. Through this process, the DOWH engineers and many of the site supervisors, laboratory technicians, equipment operators, and contractors have not only gained a wealth of experience but also increased their knowledge and became well acquainted with the application of this approach.

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