Finding a way to balance road performance, limited budgets and tightening environmental regulations is an increasing challenge for road engineers and contractors in both the public and private sectors. Treatments that improve the long-term performance of conventional pavements are becoming less and less cost-effective. Road budgets – especially for maintenance, seem to shrink annually relative to the task at hand. Common solutions such as gravel and well-graded soil for upgrading road structures are becoming less available, increasingly expensive, and are less compatible with the ecological mindset becoming more prevalent in decision making processes.
The application of Zym-TecTM requires no specialized machinery or construction procedure. The standard method for the construction of a gravel layer is followed using a water truck, motor grader and compactor, with the addition of thorough soil breakdown and mixing (see Construction procedure).
The Zym-TecTM technology also offers a unique road rehabilitation solution. The solution effectively reuses 100% of the existing materials, by scraping off the asphalt and top aggregate layers, grinding all of the materials together, mixing in the Zym-TecTM solution, re-laying the resulting aggregate mix, and compacting.
With a rural (gravel or dirt) road, the wearing course is creted from the local soil. Clay content of soil – traditionally the culprit in road degradation – is a welcome ingredient in the mix. Zym-TecTM neutralizes the negative aspects of this clay content and allows far greater densities to be achieved with the same material. This higher density results in a greater resistance to abrasion, improved load bearing capacity, and lowering of material loss at the surface and thus reducing dust.
The Zym-TecTM treated layer does not absorb water, thus mud and other associated wet weather problems are minimal during wet seasons. The road surface does not suffer from expansion/contraction cycles. As a result the required maintenance to the road is greatly reduced (often eliminated), thereby creating a substantial cost saving to the road authority.
The life of an unsealed Zym-TecTM road is dependent on the local soil used, traffic type and volume and design (the provision of adequate drainage is essential).
With a paved road, the main selection criterion of a suitable material for the subgrade layer is its load bearing capacity. Materials with clay content have a tendency to absorb water after compaction, resulting in expansion/contraction cycles which weaken the layer and lead to a lowered load bearing capacity. Zym-TecTM corrects this problem, effectively negating the water absorption, so that these materials retain thes high-compaction densities and retain their desired qualities. As treatment with Zym-TecTM is permanent, the only required maintenance to a Zym-TecTM -sealed road is that to the seal.
Any traditional wearing course can be selected – asphalt, concrete, etc. – and the application methods remain unchanged. With appropriate road structure design, the thickness of the wearing course may be reduced without sacrificing on performance, yielding additional cost savings.
Soil treated with Zym-TecTM features
- Load Bearing capacityFor roads with 15 cm to 30 cm surface thickness; Up to 10,500 kg per wheelFor roads with 30 cm to 60 cm surface thickness; Up to 14,500 kg per wheel.
- Effect of Ambient TemperatureZym-TecTM roads are used in regions with temperature ranges from – 30 0C to + 50 0C with only routine maintenance.
- Water AbsorptionZym-TecTM constructed roads, airport runways and containments have water permeability of less than 1 x 10-6
- Freeze – Thaw Cycles
Freeze – Thaw cycles have no effect on roads and airport runways constructed with Zym-TecTM.
i-Tec-India provides a variety of solutions based on its Zym-TecTM soil stabilization technology. One of the solutions that i-Tec-India provides is ecological low cost housing, based on building materials manufactured from local soils.
- An industrial-grade brick manufacturing plant, producing ecological bricks and other building materials, based on local soils as the primary raw materials With simple mould changes, a wide variety of the building materials required for housing can be produced.
- For remote and less accessible construction sites, where logistics is complex and costly, a self-sufficient building site is created. The construction is based on mixing the in-situ soil with the Zym-TecTM formula, and production of bricks and other building materials on-site with a brick manufacturing machine that is towed to the location by any pick-up truck. The Zym-TecTM technology offers tremendous cost advantages over the older brick and mortar technology . I-Tec-W provides the mobile brick manufacturing machines to facilitate this process.
- The main advantage of this technology is using in-situ soil as the primary raw material in the production of bricks and other building materials. This method is more cost effective, faster, self sufficient on-site, and provides pride of ownership for home-owners building their own houses.
- Bricks are made from the local soil, so only the Zym-TecTM solution needs to be transported. The bricks are ready for building with/without mortal after 3 days of curing
- The use of Zym-TecTM bricks and building of walls without mortar saves on cost and reduces the building time
- The thermal efficiency of i-tec-India bricks reduces the outside temperatures from 350C to a mild 200C inside the structure. The “High Thermal Capacity” of the bricks, absorbs the high outside temperature, leaving the inside of the structure cool and comfortable without the need for air-conditioning
Stages of work
Bricks are cheaper to produce:
- Local soil constitutes the bulk of raw material use
- Transport cost are minimized, production on-site
- Local labor is used
The cost of labor is reduced:
- Bricks are interlocking largely dry-stacked (with no mortar)
- Little skilled construction labor is required
- Construction is faster
- Curing timeThe compressed brick may be used to construct a wall right out of the machine (3 days of curing recommended)
- Load bearing capacity of a brickBrick strength is determined by the soil type used and the extent of curing after manufacture. Zym-TecTM bricks attain 8 MPa or higher modulus of rupture.
- Thermal qualityUp to 3 times higher than conventional products. Withstands temperatures of 1200 0C
- Permeability rating of a finished brickBricks do not absorb or allow moisture to penetrate any more that 2.5 % of the brick’s dry weight.
Another of the wide variety of solutions based on the Zym-TecTM technology is the manufacturing of construction infrastructure products. The main benefit of this application is the significant saving of cement in the production process and improvement of the compressive strength. Due to the unique Zym-TecTM characteristics, a reduction of between 50% to 80-% of the cement content in infrastructure/cement products is possible, while retaining the industry specifications of strength and hardness of the specific product.
Products within this category include:
Adding Zym-TecTM into the concrete mixture, enables significant reduction in cement content while retaining the performance characteristics. This leads to Ecological Construction and carbon footprint reduction coupled with significant cost savings. This is a patented i-Tec-W solution.
The Zym-TecTM-4 product at the core of this application is expected in the market toward the beginning of 2012.
The Zym-TecTMtechnology enables recycling of waste materials by mixing them with the local soil as part of any of the following Zym-TecTMapplication solutions:
- Road infrastructure
- Low Cost housing
- Infrastructure products / cement products
The inherent benefits of combining the recycled materials into the other processes are:
- Further cost reduction
- Significant contribution to the environment
- Providing a productive solution for many waste sites
- Turning waste sites into revenue sources
Types of waste material that can be thus utilized include:
- Fly ash
- Quarry waste products
- Mine wastes
- Building waste materials
- Road reconstruction waste materials
- Organic wastes
- Wood chips and wood industry waste products
- Among others…..