UN Choses Neoloy® Tough Cells to Rehabilitate Key Airfield

THE CHALLENGE

The Rubkona (Bentiu) airfield in Unity State is a focal point for UN humanitarian relief operations in an impoverished region. Large amounts of essential aid to hundreds of thousands of people suffering from food insecurity, displacement, and chronic under-development is flown into area on a regular basis. But the unpaved airfield suffered from continuous degradation, requiring frequent expensive maintenance, endangering aircraft operations and impairing the steady supply of critical aid.

UNMISS and UNOPS (United Nations Office of Project Services) issued an international tender for the rehabilitation the Rubkona airfield including the runways, taxiways, aprons and access roads, including drainage and double the runway size to accommodate larger aircraft.

UN SELECTS NEOLOY® TOUGH CELL

The UN selected PRS and the Neoloy Tough Cell pavement reinforcement solution based on the following factors: engineering design, cost, delivery time, sustainability, design-life and maintenance. The PRS’ detailed pavement analysis and design report provided an optimized design for the airport pavements with benefits far exceeding that of any other soft cell or geosynthetic design:
• 15-30% higher performance – low deflection, vertical stress
• 25-40% reduced pavement thickness – with improved performance
• 25-45% reduced construction time
• <2% permanent deformation for project lifespan
• Lower costs – for initial construction and maintenance

“The renovation is the best possible gift to the people in the area. We extend our appreciation to UNMISS … for this project, which they are executing nicely. This will become lifeline for most of our civil
population, and we see Rubkona becoming a hub in the region,” LAM TUNGUAR, MINISTER OF INFORMATION, NORTHERN LIECH

CONVENTIONAL SOLUTION

The PRS Engineering design report examined conventional solutions based on the design criteria – deflection and vertical strain – and the impact on performance and maintenance. Conventional pavements required prohibitively expensive thick layers with quality gravel, while HDPE-based soft cell solutions could not meet the loading requirements and design life without excessive repairs and maintenance.

NEOLOY TOUGH CELLS SOLUTION

The UN chose Neoloy Tough Cells based on the PRS Engineering design report, which detailed the planning methodology to achieve the optimized pavement – in terms of performance, maintenance and cost.
The mechanistic design analysis validated the Neoloy Tough Cell parameters required for long term soil stabilization:

• High elastic stiffness – for stable elastic behavior under heavy dynamic loading
• Low permanent deformation (creep) – maintains the long term geometry and confinement for the design life
• High tensile strength – strength of the cell to handle large vertical strains

The high-performance parameters of Neoloy Tough Cells enable the airfield pavements to withstand the high traffic loads as in the project – with low degradation and low maintenance. And this is achieved with a 25% (roads) to 40% (airstrip) reduction in pavement thickness and using locally available sandy soil for the main pavement material. With the Neoloy Tough Cell solution, only periodic surface grading and leveling maintenance is needed. Other solutions would have require imported graveling and re-surfacing operations, due to excessive degradation of the wearing layer. In terms of logistics, PRS was able to deliver the entire quantity of several hundred thousand sqm within 10 weeks to Mombasa Port to meet the UN’s urgent needs.

BENEFITS

• Guarantee the supply of essential aid to people facing food insecurity, displacement and disease
• Cost-effective – low construction and maintenance costs
• Quick implementation – simple logistics and installation, up to 45% faster construction time, to prevent interruptions in supplies • All weather pavement – to enable steady supply of aid yearlong even during rainy seasons
• Low maintenance – reliable long-term performance with minimal maintenance to ensure airfield operations
• Sustainable – locally available soil used for pavement

PROJECT AT A GLANCE

Application
Load support – airfield pavements

Subgrade/Soil
Murram – red sandy clay soil with gravel
Region
East Africa
Installation
2018
Clients
UNOPS – United Nations Office of Project Services – UNOPS helps the UN and partners provide peace and security, humanitarian and development solutions. UNOPS’ services cover infrastructure, project management, procurement, financial management and human resources. Their partners call on them to supplement their own capacities, improve speed, reduce risks, boost cost effectiveness and increase quality. UNMISS – United Nations Mission in South Sudan – is a regional peace force to consolidate peace and security – the protection of civilians, human rights monitoring and support for the delivery of humanitarian assistance – and help
establish conditions for development in South Sudan.

ABOUT PRS
PRS is the world’s leading supplier of cost effective soil stabilization solutions. Combining unique proprietary technology with specialized engineering expertise, PRS delivers proven solutions for load support, slope and channel protection, earth retention and reservoir & landfill applications. With a global network of fully owned subsidiaries and independent local distributors, PRS provides a full range of end-to-end support services.
Since its establishment in 1996, PRS has implemented thousands of successful projects in over 80 countries worldwide.