Use Advanced Technology and Sand for Highway Construction
Neoloy® Tough-Cells double the lifespan of highway using locally available sandy soil.
The Western High-Speed Diameter Road (WHSD) is a 40 km North-South 4-8 lane motorway built to relieve congestion in St. Petersburg. It was the first urban high-speed toll road in Russia, with a planned traffic capacity of 1,000,000 vehicles monthly.
The original plan for the 26 km northern section called for a conventional pavement design on top of a road embankment and 1.0m thick working platform of sandy soil. This was comprised of a 70 mm subbase layer, 410 mm thick granular base layer and a 230 mm thick asphalt layer.
Neoloy Solution – Verification
An alternative design was presented to the NHC consortium responsible for the project, and a proof of concept project was implemented on a section of the A-118 Motorway. Based on Neoloy® Tough-Cells, the goal of the design was to replace the expensive imported granular materials with locally available infill..
Stress monitoring by cyclical plate load tests (Russian standard: GOST 20276-99) of pre-installed pressure cells on sand subgrade verified that the Neoloy Tough-Cell design improves the granular subbase modulus by a factor of 2.45. It also reduced vertical stress by ~50% and allowed a 13% reduction in asphalt thickness.
The demonstration project convinced the project’s commercial and technical experts to adopt and implement the Neoloy Tough-Cell based design for the WHSD road project.
The Neoloy Tough-Cell is a 3D mechanical stabilization technology which stiffens the confined layer. The unique properties – high dynamic stiffness, creep resistance and tensile strength – of the Neoloy novel polymeric alloy (NPA) enable the following design benefits:
- Increased modulus of granular layer (2.45x)
- Decrease in accumulated plastic strain in lower granular layers
- Lower tensile strain at bottom of asphalt layer leads to lower fatigue, higher design life (x47%)
The Neoloy Tough-Cells also reduce vertical stress by 50% with a significant decrease in the pavement thickness, while improving traffic capacity and pavement design-life.
Delivery and installation were undertaken to the full satisfaction of the clients. The road is in operation since 2013 with no maintenance required.