Project
The R21 highway (designated M18 until 2018), or Kola Motorway, is a major Russian highway connecting Saint Petersburg to Murmansk. St Petersburg is the second-largest city in Russia. Murmansk is the largest city in the world north of the Arctic Circle. The 1592km highway is part of European route E105. It is the main transportation route by road in the Republic of Karelia and the Murmansk Oblast.
The Kola motorway was originally constructed in 1986. By 2006, the pavement had reached its design life. Reconstruction was required in many sections.
Design options
Two flexible pavement design options were considered for the base layers; unbound granular and bound.
Design Option 1 – Unbound granular
The unbound granular design option consisted of a crushed stone base (2 layers, total 23cm) on sand sub-base. Total depth was 59cm-79cm to achieve the required strength and resilient modulus according to BCH 46-83. Indicative cost was 3820 rubles/ m2.
Design Option 2 - Bound
The bound design variants consisted of a base/sub-base layer of medium sand bound with cement and enhanced by Renolith (aka NTS or ‘NanoTerraSoil’) admixture.
Layer thicknesses were calculated achieve the required strength and resilient modulus according to ODN 218.046-2002. Variations of the bound layer were designed, depending upon the traffic conditions in each section. The bound layer costs were estimated at 1229 rubles/m2 to 1955 rubles/m2, depending upon thickness and strength grade.
4.1.1 The strength of the treated material and reinforced soil at the design age is characterized by the brand. The ratio between the strength grade and compressive strength and flexural tensile strength must comply with the requirements specified [below].
Various wearing course options were available:
- Black gravel on recycled bitumen slate emulsion with double superficial processing
- Triple surface treatment
- Dense asphalt concrete
Assessment
A working group including eminent experts was formed to assess the technology. The working group examined the trial pavement constructed at the MADI test field, Moscow. https://renolith.com.au/madi-trials/
Design decision
The bound design option (sand + cement + Renolith) was selected for several reasons:
- significant construction cost savings (~50% overall),
- reduced maintenance costs
- longer predicted pavement life
- high frost resistance, due to extremely low water absorption
- ability to continue construction at low temperatures (as low as -10°C).
Construction
The base construction was approved to proceed in accordance with GOST Standard 81329147-012-2008 Arrangement of bases strengthened with polymer cement mixture with polymer additive “Nano Terra Soil” [Renolith], which specified:
- Soil suitable for the production of the polymer cement concrete mixture – appropriate GOST 8736, GOST 25100, GOST 23735. The soil according to GOST 23558 should not contain humus more than 2%, gypsum more than 10%, lumps of clay larger than 5 mm more than 20 % by weight.
- Cement must meet the requirements of GOST 10178, grades not lower than 300 for bases and 400 for coatings, and belong to the types of PC 300, PC 400, PC 400-D0-N, PC 400-D20-N, PC 500-D0-N, PC 500-D20-N.
- Water must meet the requirements of GOST 23732. Maximum salt content should not be higher than 10000 mg / l, incl. ions SO4 – 2700 mg / l and Cl – 3500 mg / l.
- NTS (aka Renolith) additive meeting the requirements of GOST International Standard WTO 01393728-011-2008 – Polymer Additive Nano Terra Soil – Specification. The additive is used only at positive temperatures.
- For the production of the polymer cement concrete mixture, an automated mixing plant Bertoli ECOTECH 150 continuous action with a forced mixer must be installed.
- The production of works on laying the polymer cement concrete mixture can begin after the establishment of constant average positive air temperatures in the construction area, thawing and drying of the working layer of the roadbed. The work ends approximately 18 days before the establishment of constant negative temperatures. In any case, before freezing, the reinforced material must gain 70% of the design strength.
Construction proceeded generally in accordance with GOST 81329147-012-2008, noting the following:
- A ‘double concentrate’ (reduced water) variant of the NTS/Renolith additive was developed for and used in the project to reduce the logistics (transportation) impost. The double concentrate formula was subsequently branded as ‘NTS-50’, then ‘Renolith 2.0’.
- At one point during construction a freeze of minus 25 degrees C was experienced. No damage to the freshly laid pavement was observed.
In-service
As of 2023, the Kola Motorway remains in service and generally in good condition.
Conclusion
A flexible pavement design incorporating a bound base/sub-base layer and thin asphalt wearing course was selected for the Kola Motorway reconstruction. This approach reduced construction and lifecycle costs. The inclusion of NTS (aka Renolith) admixture was essential to achieve the design tensile strength, modulus and frost resistance criteria. Construction was successful, despite extreme low temperatures. The pavement remains in-service with no significant signs of deterioration after >14 years.
Excerpts from NTS/Renolith specific Tests, Standards & Certificates in Russia (English translation)
GOST International Standard WTO 01393728-011-2008 – Polymer Additive Nano Terra Soil – Specification, 2008
This standard applies to the additive polymer “Nano Terra Soil” – NTS [aka Renolith] (hereinafter referred to as additive), intended for stabilization (strengthening) of soils with using cement and water used in accordance with the design solutions for construction, reconstruction and repair:
– highways and structures on them;
– airfields;
– areas for various purposes;
– temporary roads and sites during construction and installation works.
The requirements of this standard shall be observed in the development of the design and technological documentation for the manufacture and use of the additive.
The additive consists of polymers: a mixture of latex and cellulose dissolved in water, and is environmentally neutral and non-toxic additive for use in the process of earthworks for improvement, strengthening and stabilizing the soil with hydraulic binders.
Polymer cement concrete mixture (hereinafter referred to as PCGS) with the polymer additive “Nano Terra Soil” – NTS [aka Renolith] (hereinafter referred to as the additive), is used for the construction of the foundations of road pavements. It is possible to use the CPGS as the lower layer of the coating, provided that the wear layer is protected and the transport performance quality of the roadway is ensured. As well as:
– airfields;
– areas for various purposes;
– temporary roads and sites in the performance of construction and installation works.
Certificate of Conformity, Polymer additive Nano Terra Soil, 2009
Product
Polymer additive Nano Terra Soil [aka Renolith]
Produced according to manufacturer’s normative documents
Meets the requirements of normative documents
STO 81329147.01-2008, GOST 23558-94
Certificate of Conformity, Polymer cement soil mix with polymer additive Nano Terra Soil, 2009
Product
Polymer cement soil mix with polymer additive Nano Terra Soil [aka Renolith]
Manufactured according to STO 81329147.01-2008, STO 81329147.02-2008 Serially
Meets the requirements of normative documents
STO 81329147.01-2008, STO 81329147.02-2008, GOST 23558-94 and GOST 30491-97
Scheme 3 certification
The list of specific types of production for which the certificate of conformity is valid:
- M20 brand, material – coarse sand
- M40 brand, material – coarse sand
- M60 brand, material – coarse sand
- M20 brand, material – solid loamy fine sand
- M40 brand, material – solid loamy fine sand
- M60 brand, material – solid loamy fine sand
- M20 brand, material – light clay soil
- M40 brand, material – light clay soil
- M60 brand, material – light clay soil
- M20 brand, material – gravel-sand mixture
- M40 brand, material – gravel-sand mixture
- M60 brand, material – gravel-sand mixture