Trisoplast® is an innovative mineral sealing material that offers a number of significant benefits in comparison with the traditional mineral liners. In the Netherlands it was developed to technical maturity and successfully tested by independent testing laboratories regarding its performance. Since 1992 an increasing number of European and non-European countries have already approved it as a sealing barrier for various applications and as a result it is more commonly the preferred option. Independent testing and ongoing research has already confirmed its outstanding performance.
Trisoplast® is a registered trade mark. The system was developed by Trisoplast Mineral Liners and is protected by patents. Trisoplast® is produced under the license of Trisoplast International.
Trisoplast® consists of the following main components::
- Granular component, e.g. sand
- Bentonite
- Polymer
The components are mixed in mixing plants and small amounts of water are added if required. Thus Trisoplast® is installed and compacted at water contents close to but below the proctor optimum, in a first step the bentonite powder and polymer powder are blended, secondly the sand and the bentonite- polymer pre-mix are mixed in a forced mixer to achieve a homogeneous material.
In order to control the dosing of the components the water contents of the bentonite and the granular component must be determined in advance and taken into account when calculating the masses for the correct settings of the mixing plant.
The finished mixture is loose, has a granular appearance, is lumps free and easy to handle. The Trisoplast® mixture is handled and compacted with conventional earth construction equipment (telescopic or long-reach excavators and rather light, smooth drum rollers/compactors) in a single layer on a well prepared subgrade of sufficient load bearing capacity. The initial moisture content at mixing causes a first initial binding within the material resulting in a cohesive material which is positive for creating a well compacted layer.
A unique clay-gel is formed from a mixture of sodium activated calcium bentonite and polymers, as soon as additional moisture reaches the applied layer. A very compact gel structure is developed by the network of chemical compounds formed by the clay mineral particles and the polymers (see Figure 1 for further details).
Trisoplast® shall be installed on a dry, well compacted (so that it does not subside) and stable subgrade and requires (as all bentonite based mineral seals) a sufficient surcharge of at least 5 to 6 kN / m2 (equals approximately 25 to 30 cm of covering soil or equivalent). For landfill applications a thicker cover layer (normally at least 1 m) is commonly used. In any case the design for a project depends on the application and remains the responsibility of the design engineer.
In comparison with conventional barriers, consisting of natural clays and compacted wet of optimum Trisoplast® has the following essential advantages:
- very homogeneous sealing material made of defined components, manufactured in highly accurate mixing plants under application of quality assurance measures: due to the low diversification of the material properties, the non-existence of excessive particle sizes, the low water permeability and the low compaction requirements the material can be applied in a single layer of low thickness.
- very fast application, therefore considerably better coordination with the company laying the geomembrane and early protection against weather influences
- lower material consumption and less transport efforts
- no danger for the geomembrane caused by oversize or sharp particles
- considerably better crack-free deformation: construction of the final sealing system there- fore already possible on areas sensitive to settlement without any additional temporary measures
- better long-term performance due to a considerably reduced risk of desiccation and shrinkage cracks (compaction dry of optimum water content, delayed liberation of water due to the insulating effect of the polymer)
- better long-term performance due to the considerably slower liberation of water to plant roots
- better long-term performance due to the inhibition of the ion exchange
- thinner layer thickness and possibly higher waste disposal volume
Trisoplast® is used for the sealing of building pits, storage areas, foundations, noise insu- lation walls, as well as waste disposal sites and contaminated sites. In the Netherlands Trisoplast® was tested, evaluated and approved for use in waste disposal site sealing systems by various official and independent private sector institutes under supervision, of NOVEM (Nederlandse organisatie voor energie en milieu - Netherlands State Agency for Energy and the Environment). Since then more than 4.6 million m2 (in December 2003) have been sealed with Trisoplast® in the Netherlands from which: 1.2 million m2 bottom liners, 2.6 million m2 in landfill covers and more than 0.8 million m2 for other applications. Further applications in the field of waste disposal and contaminated sites were realized in the following countries: Germany, Belgium, Finland, Sweden, Italy and Romania.
In Germany Trisoplast® was also examined by the working committee "Trisoplast®", formed by the representatives of the responsible environmental agencies as well as inde- pendent experts from universities, federal agencies and consultant engineers and scientists. Trisoplast® has passed all tests and has been approved as being generally suitable for the surface sealing of waste disposal sites in August 2002.The working committee concluded that 7 cm Trisoplast® are equivalent to the 50 cm thick Mineral Barrier according to TASi (German Landfill Directive). Trisoplast® has already been applied on 7.5 ha in 2 projects in Germany (August 2002). Since then Trisoplast® has been applied in many projects in Germany.
In Romania, Trisoplast® was applied for a hazardous landfill in Cluj, belonging to a pharmaceutical factory TERAPIA SA. For this landfill, our company, IRIDEX GROUP CONSTRUCTII, had won the QUALITY TROPHY of 2005, awarded by ARACO .
