Asphalt emulsions are a scientific marvel – one that can protect driveways, parking lots and many other high traffic areas. Like applying wax on a car, asphalt emulsions provide an additional layer of defense from the elements, and they also improve the load-bearing potential of the pavement.
Asphalt emulsions can be applied to asphalt and concrete surfaces, rejuvenating aging pavements, extending their life and making repair easier to manage.
What Is An Asphalt Emulsion?
Emulsions are everywhere, maybe in your stomach if you’ve eaten recently. Every emulsion consists of tiny droplets of one liquid, mixed with another liquid that it normally wouldn’t be soluble in. Vinaigrettes and butter are two such examples.
The addition of a surfactant improves the emulsion’s stability by binding to the droplets and boosting their solubility. Most surfactants have a hydrophilic (dissolves in water) end and hydrophobic end (which does not dissolve in water).
An asphalt emulsion contains water and asphalt cement droplets. The surfactant bonds with water and with oil in the asphalt, greatly reducing the viscosity of the material. That’s one of the major benefits of asphalt emulsions because they can be poured and spread like a fluid. This makes the application process easy for a contractor crew to manage.
What Are Some Asphalt Emulsion Applications?
Asphalt emulsion application can improve the condition and appearance of a variety of surfaces, so you may find it on:
- Asphalt pavement
- Concrete paving
- A business parking lot
- A driveway
- An airport runway
The emulsion product can be applied to aging pavement or immediately after road construction like a finish or sealer. This will enhance the surface’s durability, offering protection from sunlight and oxidation, protection from various chemicals, and improving weight bearing capacity. Use of asphalt emulsion on concrete and asphalt pavements also reduces the likelihood of cracks, riveling and pockmarks forming.
Prior to application, the contractor’s team will clear the area of any type of debris. From here, there are several application methods to consider. A few of those methods include:
- Tack coats – A tack coat is sprayed onto existing pavement using an asphalt applicator. Once applied, a new layer of pavement can be placed on top of the tack coat. The purpose of the tack coat is to strengthen the bond between the old and new pavement, as well as enhance the new pavement’s fatigue resistance.
Ideally, the tack coat will be applied in a thin layer, won’t run off the road and won’t result in slipping between pavement layers.
- Chip seals – During chip seal application, a layer of asphalt emulsion is sprayed over the pavement. A layer of fine aggregate is then evenly distributed over the emulsion. In some cases, the process is repeated to produce a double chip seal. Once the aggregate is placed on the asphalt, it’s pushed into the pavement using heavy rubber rollers. The result is a durable, though slightly rough surface finish.
Chip seals are a popular preventative maintenance option, as they are quick and cost effective to apply. They have limited utility in road repair, as chip seals are only intended for fixing small cracks. Chip sealing can improve waterproofing and defend against oxidation and other forms of wear.
- Slurry seals – Slurry seals are made with a combination of asphalt emulsion, minerals and aggregate, applied using a single machine. This mixture is laid directly over the existing pavement and provides a strong seal against wear and damage. Slurry seals also offer excellent skid resistance, and they can be driven on just a few hours after placement.
There are a few types of slurry seals. The only difference between them is the size of the aggregate included in the mix. Type I utilizes fine aggregate that’s appropriate for parking lots. Type II uses a moderately coarse aggregate that’s better for residential roads and highways. Type III makes use of the coarsest aggregate available and works best for interstates.
- Microsurfacing – Microsurfacing is similar to a slurry seal, but uses a slightly different set of ingredients, like dense aggregate and emulsion modified with polymers.
The microsurfacing process leaves a stronger and longer lasting finish. It’s also quick to place and dry and is one of the most cost-effective options available for pavement protection.
Beyond these, asphalt emulsion may be used in extensive recycling or reclamation projects.
What About Coal Tar Emulsions? How Do They Compare to Asphalt?
Coal tar was once the preferred emulsion sealer and remains a popular option, but asphalt emulsion is quickly replacing it for a few reasons, including:
- Additional solids – Asphalt emulsions contain more solids than coal tar, and it’s these solids that are left behind after the emulsion destabilizes and water evaporates. With more solids to work with, asphalt emulsions last longer than coal tar, which can be watered down to a much greater degree.
- Works better with other asphalt materials – Coal tar and asphalt are completely different materials, so it’s no surprise that asphalt emulsions are a better fit for asphalt pavements. Coal tar forms a rigid layer that will not expand like asphalt when it’s heated. As a result, coal tar can begin cracking soon after it’s placed.
- Blends in with concrete and asphalt better – Coal tar has a bluish color once it dries and it produces an unpleasant, pungent odor. Asphalt emulsion looks like asphalt and smells like asphalt, which has little to no odor.
- Minimal exposure risks – Asphalt emulsion is safe to work with and casual exposure generally poses no risk. That’s not the case with coal tar, which is unsafe on multiple levels. For one, coal tar will burn any skin it is exposed to. It also emits certain types of aromatic hydrocarbons that are linked to several health problems.
Most concerning of all, coal tar exposure is associated with increased risks for several types of cancer, including skin, lung, gastrointestinal, kidney and bladder cancer.
We Can Provide the Equipment, Manpower and Expertise for Any Asphalt Emulsion Project
Asphalt emulsions reduce the cost of maintenance and protect your asphalt and concrete from many types of stress. Compressive stress, chemical stress, thermal stress – asphalt emulsion will improve your pavement’s performance against them all.
The team at American Parking Control is experienced in a variety of asphalt emulsion applications and have the manpower to complete your project on time and within the budget.