Road & Pavement Construction & Maintenance

In road construction there are three primary factors that cause deterioration over the life of a pavement and result in costly maintenance. They are:

1.  Lack of Moisture during Construction

Compaction is a very important component of road construction and difficulty is often encountered in achieving the required level of compaction in the sub-grade material due to a lack of moisture content. This is most notable when mixing water into materials such as heavy clays or fine silty sands containing humic matter.

To overcome this, we developed ROADBASE MIXING AGENT, a powerful wetting agent, to provide an efficient and inexpensive means of increasing the moisture content of materials. By mixing this environmentally friendly wetting agent in a water truck, we can increase the effective use of the moisture for virtually any natural or processed road construction materials.

ROADBASE MIXING AGENT breaks down the surface tension on the soil particles to allow water to penetrate the ground instantly which eliminates run off and surface evaporation. This product has enabled very significant cost and time savings of both labour and machinery during construction as well as dramatically reducing the water usage. Our clients have claimed up to 35% reduction in water.

Application rate: ROADBASE MIXING AGENT is normally mixed at the rate of 1 litre to 2000 litres of water. Often it is used at 1 litre to 5000 litres of water.

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2.  Water Ingress into Finished Roads & Unsealed Pavements

Once a road pavement has been compacted, whether sealed with asphalt or remaining unsealed, the ingress of water into the sub-grade materials is the major cause of all road failure. This is regardless of whether it penetrates through the asphalt surface, enters through the shoulders or seeps into the sub-grade by means of capillary action aided by the pumping action of traffic passing over the surface.

By preventing water penetration into the road pavement materials, the sub-grade materials remain at their optimum compaction preventing deformation in the road surface. Hence maintenance costs for pavement failure and dust control are dramatically reduced.

DUSTDOWN is a blended compound with highly exceptional water repelling properties which, alone or in combination with other binding compounds, allows long term stabilization of particulate material such as in-situ materials in unsealed roads and production run (quarry) materials for sealed roads.

This product is designed to be applied simply and cheaply using a water truck and sprayed onto the road materials before compaction or pug milled at the quarry and delivered to site for compaction.

The ability to adjust the application of DUSTDOWN enables road pavements to be constructed in almost any material at hand even waste materials such as coal dust or tailings from mines.

Note: Crusher Dust containing DustDown remains intact compared to Crusher Dust with no treatment

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3. Erosion of Unsealed Roads or Aprons

The interaction of tyres with an unsealed road surface displaces fine road particles that can be either blown away with passing traffic, causing dust problems, or washed from the surface by rainwater.

The problem is that water saturates the road base material and over time the vibrational energy from vehicles passing over head vibrates the road. And in doing so the fines in the road base material float to the top of the road surface. Additionally, the traffic creates wind erosion causing ruts and potholes.

To alleviate this mechanism, DUSTDOWN creates an interrupt layer and works very effectively in keeping the water out of the in-situ road material to prevent fines from migrating to the road surface. As a consequence, dust is significantly reduced, and the maintenance is pushed thus reducing the cost of road maintenance. This provides a very durable, low cost road for all environments.

The benefit to our clients is that the periods between maintenance are much longer than roads untreated.

Laboratory trials have shown that road pavement materials treated with DUSTDOWN have remained fully intact when completely and continuously submerged in water for over seven (7) years without deforming or losing any strength. Untreated control materials totally collapsed within 20 minutes of being submerged and some within seconds (refer photo above.)

Field trials have been conducted in both low and high-volume traffic areas with great success. Roads treated with DUSTDOWN have been subjected to very heavy traffic loadings together with high rainfalls with little or no erosion.

DUSTDOWN also has application on the unsealed apron immediately next to the asphalt on a sealed road. This section of a sealed road often erodes by wind action of particulate fines from passing traffic leaving a deep shoulder which, according to traffic engineers, occasionally causes traffic accidents to occur. Application of DUSTDOWN to these aprons reduces the height of the shoulder that forms over time thereby reducing the amount of maintenance to fix shoulder damage. More importantly application of DUSTDOWN can therefore increase the safety of high use roads.

Left Hand side shows untreated side road with loose gravel compared to treated roadway which has remained hard.

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4. Dust Control of Haul Ways and Traffic Areas

As noted above dust can be controlled by adding DUSTDOWN to the in-situ materials which prevents erosion of the soil. Alternatively, dust can also be controlled by traditional methods such as watering the road regularly using a water truck. However, compared to simply using water alone, the use of ROADBASE MIXING AGENT employed in the water truck makes more effective use of water sprayed on haul roads to control dust.

ROADBASE MIXING AGENT reduces the surface tension of the water on the soil particle surface. The water penetrates into the road structure instead of sitting on the road’s surface and running into the water table or evaporating from puddles on the road.

It has been shown that when using ROADBASE MIXING AGENT, the amount of water used is about one third less than using water alone. When constructing a road in a remote location, this equates to a lot less truck loads and hence the cost of watering is about 30% less.

Quarrying

Dust created during quarrying operations can be hazardous to workers and nearby neighbours particularly if the dust particles fall in the PM 10 range which are known to cause silicosis, a disease of the lungs.

1. Dust Control in the Crushing Plant

In order to control air borne dust at transfer points in the crushing and screening process, pressurised water sprays are generally used.

A very significant problem point is at the end of the road base stacking conveyor. In spite of the amount of water employed at this point, we still experienced an unacceptable amount of air born dust, free water could be seen running away from the base of the road base heap and the product emitted clouds of dust as it was re-handled according to Neilsen’s Quarry.

They then installed a 10,000 litre tank with a small electric pump to supply the water sprays. Each day the tank is topped up with water and WET IT DOWN is added at the rate of one litre for every two thousand litres of water.

For the same amount of water employed through the same water sprays the air born dust has virtually been eliminated at the head of the stacking conveyor.

All of the water from the water sprays is now absorbed into the road base and there is no free water running away from the base of the stock pile. Air borne dust from the re-handling of this product has been eliminated.

Our customers are aware of the reduced amount of machine time required to place the product and the reduced amount of water that needs to be applied to achieve compaction on the job. “Our laboratory tests have indicated a more effective absorption of this treated water into the road base matrix and an improved density”.

Another significant problem point is the bottom of the crusher. Crushed material falls onto a conveyor line and, in doing so, creates dust. SGG has created a foam designed to capture the dust particles then the foam collapse within 15 seconds.

The benefit to the quarry is that:

• The foam (CONVEYOR FOAM) is most effective in capturing fine dust particles compared to water

• Uses less water

• CONVEYOR FOAM collapses quickly allowing the captured dust to settle onto the conveyor line instead of causing large amounts of foam with dust particles to spill out onto the ground causing runoff and a mess around the crusher.

• The amount of fine dust around the crusher plant that can cause respiratory diseases such as silicosis is reduced.

Any transfer point between conveyor lines can be a point of dust emission. CONVEYOR FOAM can capture dust particles at any of these points.

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2. Sand Laundering

During the sand laundering process, two sand tubs are employed in series.

In order to more efficiently wash the slimes and micro fines from the raw feed material, WET IT DOWN is added to the wash water and introduced into the first tub via a gravity-monitoring tank.

Observing the overflow water from each of these sand-laundering tubs without the WET IT DOWN added, the water has a uniform dirty brown appearance.

With the WET IT DOWN added, in each sand tub little rivulets of clear water can be seen separating from blooms of dirty brown water before the water exits over the sand tank weirs. 

WET IT DOWN has reduced the surface activity on the sand particles thereby producing a more effective washing medium.