Crusting Chemicals and Soil Binders

Where are crusting agents used?

Surface crusting or soil binding using chemicals is typically done to prevent dust lift off or erosion. Some of the more specific applications include:
  • Dry tailings dam crusting
  • Stockpile crusting
  • Preventing dust from areas with topsoil and grass removed
  • Stabilising rehabilitation areas
  • Stabilising exposed sides of roads

Principles of crusting

When considering crusting agents, it is important to note that is there is a minimum strength and thickness required to achieve a stable crust.
  • A minimum concentration of crusting agent is required as a starting point. Beyond this, higher concentrations will strengthen the crust for longer duration applications.
  • A minimum quantity of dilution water is required to ensure the crusting agent penetrates to a suitable depth (for example 20mm to achieve a thick crust). Too little water will achieve a very thin crust which is easily broken by wind, heavy rain or hail events. Typically 1-2 litres per m2 is specified.

How long will the crust last?

Duration will depend on the thickness and strength of the crust.
  • A low application of crusting agent may be considered for short term crusting, taking into consideration forecast weather events (strong winds, heavy rain, hail)
  • Higher applications may achieve long term crusting, but must take into consideration worst case conditions. Crusts can be destroyed by 'extreme' weather events. Hail will puncture holes in the crust and water running over the surface can erode the material under crust destabilising it. Points of failure in the crust it will quickly undermine the whole crust as wind will flake and lift surrounding areas.
Wet Earth can specify a crusting agent and application rate to suit the site conditions.

Difficult site conditions

Some surface materials are very difficult to crust for long periods because they are made from particles that expand and contract with moisture (eg clays) which cause the surface to crack. These cracks provide points where wind can erode the crust. There can be cases where the surface crust is still ok, but material is blown out of these cracks resulting in dust lifting off the surface.

Incorporating dyes

Many customers want to include a coloured (usually green) dye in the crust. This has two purposes. The first is to assist with application by showing the areas that have been treated. This helps ensure full and even application coverage. Secondly, including a green dye provides stakeholders with a visual indication that an area has been treated. If the dye is only used as an application guide, then lower amounts can be used. If it needs to last then higher rates are used taking into account how long it should last, how bright it needs to be and the depth of colour required. It is important to note that the green dye is not colour fast with all crusting agents so the colour may fade long before the crust deteriorates.

The following are some of crusting chemicals we offer with a summary of the advantages and disadvantages of each. Please contact us to discuss your specific requirements so we can recommend the best option.

TGC - Total Ground Control

TGC is our original crusting agent and is a virgin acrylic polymer designed specifically for this purpose. There are many crusting agents on the market similar to TGC, but almost of these use waste polymers from other industries that are not designed for this purpose and frequently have about half of the active polymer compared to TGC. TGC is our recommended crusting agent in the following cases:

  • Slopes as it creates a water repelling surface that is less prone to erosion
  • Sand and non-porous materials
  • Where the lifespan of the green colour needs to be maximised
Typical application rates for TGC are 50-100ml per m2 and the crust can last up to 18 months
For more information please visit our TGC - Total Ground Control page.

RT5 Superskin

RT5 Superskin is a super concentrated polymer. Its key benefit is that only small volumes are required which make it cost effective and reduces freight costs. Its major negative is that it is a gelling polymer which means that it it a challenge to dilute and mix properly. RT5 Superskin is our recommended crusting agent where freight costs impact on its viability.

Typical application rates for RT5 Superskin are 5-8ml per m2 and the crust can last up to 12 months
For more information please visit our RT5 Superskin page.

DustWorx GX

DustWorx GX is our new concentrated polymer based soil crusting product. It is cost effective (similar in price per m2 to RT5), easy to use and dilutes and mixes readily. One of the key benefits is its ability to self repair when re-wet so it is more likely to recover from sever weather events than other crusting chemicals. 

DustWorx GX is generally our default crusting chemical except where RT5 Superskin or TGC are recommended as stated above.

Typical application rates for DustWorx GX are 30-40ml per m2 and the crust can last up to 12 months
For more information please visit our DustWorx GX page.

If you have a particular application you would like us to discuss, require project pricing or would like more information then please send an email to sales@wetearth.com.au.