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:
- Tailings dam crusting
- Stockpile crusting
- Preventing dust from areas with topsoil and grass removed
- Stabilising rehabilitation areas
- Stabilising exposed sides of roads
- Preventing/reducing erosion
Principles of crustingWhen 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.
Difficult site conditions
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
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 severe 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.
DustWorx GX is the only crusting agent suitable for use through sprinklers for the following reasons:
- it does not need time in water to activate (like gelling polymers such as RT5 Superskin);
- it will not coat and build up on sprinklers (like acrylics such as TGC); and
- it will not significantly change the viscosity of the water (like gelling polymers such as RT5 Superskin) which increases pipe pressure losses and changes the sprinkler performance.