Bitumen emulsion techniques

Bitumen emulsion techniques

Routine repairs, structural maintenance, wearing course maintenance... Bitumen emulsion techniques can meet your needs to maintain the long term serviceability of your pavement. Emulsion techniques are energy-efficient and limit greenhouse gas emissions.

Cold asphalt mixes for surface courses

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Cold asphalt mixes

Cold asphalt mixes are made with high quality aggregates and are often used in surface courses as the final road pavement.

The design of cold mixed asphalt concretes usually utilize 0/10mm or 0/14mm aggregate and a selected bitumen emulsion. These types of cold mixes offer the following advantages:

  • Low impact on the environment.
  • Ease of use (as they are stable and remain workable for several hours).
  • Remain flexible over time and are compatible with a wide range of underlying pavement materials.

The performance of bitumen emulsions makes it possible to obtain cold asphalt mixes with a good macro texture, and adhesion characteristics equivalent to those of hot asphalt mix materials.

Due to their qualities, cold asphalt mixes are particularly well suited for:

  • Pavements located in difficult climate zones (e.g. mountains, etc.).
  • Pavements that are not heavily structured.
  • Pavements subjected to low to average traffic (T2 or 300 heavy goods vehicles per day and per lane).

They are best applied with a paving machine/paver, with an average material course thickness between 30 and 50 mm.

Micro surfacing using bitumen emulsion for surface courses

Enrobé coulé à froid
Micro surfacing

This technique constitutes the thinnest mixture that can be used as a surface course. Micro surfacing is the intermediary between a surface dressing and very thin asphalt concrete.

Micro surfacing protects the underlying pavement by improving impermeability, provides excellent adhesion to the existing road, compensates for small deformations, and has no loose aggregates under traffic.

The use of modified bitumen emulsion provides a good level of adhesion and flexibility over time. The relative simplicity and the speed of laying Micro surfacing minimizes the work time.

The latest technical enhancements with these products guarantees rapid reopening to traffic and significantly reduce the inconvenience for road users.

Micro surfacing is well suited to the maintenance of rural roads, urban roads, highways and airfield runways. In some countries it often constitutes the wearing course on”grave-emulsion”base course surfacing.

Surface Dressing for the renovation of wearing courses

Surface Dressing

Most importantly, road surfaces must remain impermeable and ensure good adhesion to the existing pavement. Based on these parameters, this surface treatment has always satisfied clients due to its relatively low cost.

The daily outputs are also quite high as the Surface Dressing is rapidly applied. A surface dressing restores skid resistance and seals the road to prevent water ingress.

Surface dressings with bitumen emulsion offer some significant advantages that include: they are not very sensitive to water and to weather conditions, they allow for the spreading of the work over the course of a relatively long season and they overcome the potential problem of moist aggregates.

A variety of surface dressing treatments are available to address the specific problems of each pavement to be treated.

For high traffic or difficult conditions, the modification of the bitumen emulsions by the addition of polymers brings clear improvement to the performances of the surface dressing.

The use of these modified emulsions has become the norm in many countries. A surface dressing with bitumen emulsion is a rapid and economical solution for the renovation of the existing pavements. Its qualities also make it very environmentally-friendly.

“Grave-Emulsion” for pavement resurfacing and reinforcement

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Grave-Emulsion

Grave-Emulsion is an asphalt mix obtained from a mixture of aggregate, water and bitumen emulsion which is dosed and mixed cold. This type of treatment offers the following advantages:

  • Low impact on the environment
  • Ease of use
  • An ability to regulate existing pavements and major deformations.

Grave-Emulsion is an ideal product for the resurfacing and reinforcement of low trafficked roads as well as those that are experiencing an increase in traffic.

Grave-Emulsion has been used for more than 40 years on pavements receiving up to 300 trucks per day and per lane. Typical application thickness is around 50mm.

If the aggregates used allow for it, Grave-Emulsion surfaces can be driven on for several months, possibly even several years, before receiving the final wearing course as a step in the progressive development of the road. The final surfacing course is a surface dressing, micro surfacing or a cold asphalt mix.

Recycling of pavements on site using bitumen emulsion

Retraitement des chaussées
Recycling of a pavement on site

Recycling with emulsion allows for the reconstitution of an improved quality road structure by reusing the existing road materials.

The work is mostly carried out in-situ using specific milling / mixing equipment, this shortens the overall project completion, and limits inconvenience for road users by allowing more rapid reopening of the road to traffic.

On-site recycling follows the principles of sustainable development as:

  • Cold recycling saves energy,
  • Eliminates the majority of transportation costs as the process minimizes the use of outside materials,
  • Minimizes work site waste

This process also offers the following technical advantages:

  • It improves the overall homogeneous road structure,
  • It improves ride ability of the road
  • It treats interface bonding problems,
  • It improves impermeability of the road structure
  • It conserves the finished pavement levels to minimize further costs

This technique, which has been used in Western Europe and the USA as well as many other countries worldwide for the past 30 years, is now an accepted tool for the road maintenance engineer. Recycling can be carried out on site or in an offsite plant.

Routine repairs of low-traffic roads: surface treatments and emulsion asphalt mixes offer the best solutions

As part of its responsibilities, a road management authority must frequently deal with urgent needs for repairs of sudden and localized degradation problems of the highway network: potholes, deformation of the support, cracking, trenches, etc. These repairs are considered urgent because of the need to protect the safety of users and to preserve the road.

When the degradation does not affect the impermeability of the pavement, the appropriate solution is the application of an emulsion surface treatment. The modest scope of the areas to be treated allows for the use of automatic patching equipment or even manual application. Automatic patching equipment guarantees perfect control of the dosing and the quality of the application.

Where degradations affect the surface course throughout its thickness (e.g. potholes and deformation) the solution to these flaws requires the use of asphalt mixes. Emulsion asphalt mixes are often an excellent solution as they can be stored, they are easy to use, and they are relatively insensitive to climatic conditions. Depending on the thickness of the repair, the cold asphalt mixes can be in the form of 0/6mm to 0/14mm emulsion stabilized aggregates or 0/6mm or 0/10mm cold asphalt mix.

The fact that it can be stored (from several days to several months) makes it suitable for emergency work. Its packaging in buckets also allows for long-term storage. For the topping up or filling of trenches, these emulsion stabilized aggregates or cold asphalt mixes can make up a base course and/or a surface course for temporary and permanent solutions.

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