SoilTech Mk. III, a third generation nano-polymer binder by Polyroad, is a road stabilization agent, developed especially to strengthen rural roads where excessive loading occurs and where all-weather roads are required.
Global Rural Roads
Everything that sustains us, whether grown, mined, or drilled begins on a low-volume road. Low-volume roads transcend language, culture, topography, and climate. Due to their basic necessity, they tend to drive innovation in design, material use, maintenance, and social development.
Nearly 30 million km of low-volume roads connect the world’s population, yet, according to the World Bank, 31% of the world’s population (1 billion people) still do not have adequate access to transport. Three-quarters of the population of the 21 least developed countries do not have access to all-weather roads, which are a key diagnostic measure of development.
Accessibility, whether it is to markets, schools, health clinics, water points, places of worship, and community centers in rural areas or to the nearest town or city, is a precondition for the satisfaction of almost any economic or social need.
The World Bank and donor institutions have extensively championed rural roads as poverty alleviation instruments. Rural roads are key to raising living standards in poor rural areas. By reducing transport costs, roads are expected to generate market activity, affect input and output prices, and foster economic linkages that enhance agricultural production, alter land use, crop intensity and other production decisions, stimulate off-farm diversification and other income-earning opportunities, and encourage migration. Furthermore, by facilitating access to social service facilities, better roads enhance social outcomes.
Rural Roads Stabilization
Smart Materials challenges the core of conventional road construction and design, by bringing in unprecedented resilient modulus flexibility, which is needed for Mechanistic-Empirical (ME) road design calculations. Smart Materials reduce the number of supporting aggregate layers for cement modified /stabilized flexible and rigid road designs, thereby, substantially reducing construction costs.
Due diligence in the design process is always important for rural pavements based on the criteria and requirements which includes the characteristics of the soil, design life of the road, current traffic as well as future traffic growth.
Research over 15 years has quite clearly shown:
- the importance of adopting a more holistic, sustainable approach to the provision of low-volume roads
- the need to revise conventional approaches to planning, economic appraisal and the environment
- the shortcomings of conventional specifications and, to some extent, of test methods, in assessing the adequacy of local materials for use in low-volume roads
- the advantages of adopting more appropriate geometric and pavement design standards
- the economic success of innovative construction methods
- the importance of paying greater attention to the environmental aspects of road provision
The benefits have been numerous:
- Reduced construction time
- Minimal maintenance – longevity
- Structural strengths increases in CBR, UCS and elastic modulus <400%
- Cost effective
SoilTech Mk. III, a third generation nano-polymer binder and is a road stabilization agent. SoilTech stabilizing polymers are elastomers, which gains strength from mechanical compaction and do not become brittle when cured. The e-modulus properties of the elastomer allow the pavement to flex under heavy load. And unlike cement stabilization, will not crack under excessive loading.
The high elastic modulus and CBR strengths of material after stabilization with SoilTech, enables engineers to reduce layer-works in the pavement design. Furthermore, SoilTech MK III stabilizers have been purposely designed to penetrate through the stabilized road’s base-layer, into the sub-base layer, via capillary action, thereby, strengthening the sub-base material.
From an engineering perspective, the migration of SoilTech into the sub-base, is a unique phenomena, that improves structural strength of the roads. SoilTech enables stabilization of two layers, even though only one layer has been stabilized.
Utilization of Insitu Materials
SoilTech, in many instances, enables the use of insitu materials for base and sub-base stabilization. This is particularly useful for rural road construction. Quite often it is prohibitively expensive to bring in borrow-pit or quarry material. Furthermore, service delivery to the rural community is greatly improved as roads can be constructed substantially quicker when using insitu materials.
Black-Cotton Soils
In Bangalore, 50% material was brought in from a borrow-pit and mixed with Black-cotton soil on the Gedag-Shagoti roads and then stabilized with SoilTech. Thereafter, the roads were sealed with a concrete layer. Once again, there was no need to remove the expansive materials.
Job Creation for Rural Roads
Although, SoilTech Mk. III is a third generation and highly engineered stabilizer, the product can be applied with low-tech technology such as tractors with scarifying attachments, water trucks and compactors. If required, local population can be used for the construction of these roads.
Full training is provided by Kaveri personnel in all applications of Smart Materials supplied by the company. Obviously, using labour as opposed to high-tech machinery, prolongs the construction work.
However, if labour creation is a priority, then SoilTech is ideal as a community enabling product.
This was a project to alleviate poverty and to create income for rural people in isolated parts of the country. Rural workers using a wooden frame and hoes to profile a farm road, prior to ripping the road and stabilizing the material.
The wooden frame is ideal for maintenance of unsealed roads, as the road’s profile can be kept intact, using the local labour workforce.
Rain and poor drainage on roads, are a major factors contributing to road failures. The wooden profile is a handy tool in mitigating water damage to the road.
Case Studies
Chandrapur District - GMR Warora Roads (2016)
From a practical and economic perspective, only black-cotton soil was available for construction of the roads. SoilTech Mk. III polymer stabilizer was used to stabilize 200mm of black-cotton soil for the base-layer, using 2 litres per m2. The road was opened to traffic for more than two years before sealing with a 150mm concrete wearing course seal. During this period and throughout the monsoon, the unsealed road held up with no damage.
CBR Table – Before and After Stabilization
BS – Before stabilization, AS – After Stabilization
Hyderabad – TRRDA
Utilizing insitu materials only for the rural roads. Stabilized 100mm deep using one litre of SoilTech Mk. III polymer stabilizer per m2.
Karnataka Rural Road Development Agency (KRRDA) -
Government of Karnataka, wants to build a few hundred Kilometers of rural roads in Karnataka using SoilTech stabilizers. The first two roads have already been completed.
All roads are designed in accordance to international standards, as well as traffic loads, traffic types, traffic volumes, and expected future traffic growth. Insitu and available materials are thoroughly screened and tested to ensure optimum performance with SoilTech Mk. III nano-polymer stabilizers, prior to road designs.
