Asphalt emulsions are an environmentally friendly, energy efficient and cost effective product for use in today’s paving and preservation efforts. But, what are they and how are they made?
Emulsion definition: 1. A mixture that results when one liquid is added to another and is mixed with it but does not. Bakery Emulsions are a more flavorful alternative to baking extracts. Emulsions are in a base of water instead of alcohol, so the flavor won't bake out!
What Is an Asphalt Emulsion?
An asphalt emulsion is liquid asphalt cement emulsified in water. It is composed of asphalt, water and an emulsifying agent. The emulsifying agent is sometimes called the surfactant, which is composed of large molecules. These soap molecules are like tadpoles, having a hydrocarbon tail soluble in liquid asphalt and an electrically charged or ionic head soluble in water. The asphalt particles are surrounded by the ionic charge, which causes the droplets to repel each other and stay suspended in the water.
An asphalt emulsion is liquid asphalt cement emulsified in water. It is composed of asphalt, water and an emulsifying agent. The emulsifying agent is sometimes called the surfactant, which is composed of large molecules. These soap molecules are like tadpoles, having a hydrocarbon tail soluble in liquid asphalt and an electrically charged or ionic head soluble in water. The asphalt particles are surrounded by the ionic charge, which causes the droplets to repel each other and stay suspended in the water.
Microsoft office 2019 professional plus. All asphalt emulsions are designed to eventually break, or revert to asphalt and water. Some emulsions break by chemically destabilizing the surfactant, others by a simple evaporation of the water. Still others break by a combination of chemical destabilization and evaporation.
Today’s emulsion manufacturers have many new chemistries available to design the emulsion for the optimal break time and specific use.
How Are Emulsions Made?
Asphalt cement is the basic ingredient of asphalt emulsions. In most cases, it makes up from 50 to 75 percent of the emulsion. Some properties of the asphalt significantly affect the finished emulsion. But there is not an exact correlation between the properties and the ability to emulsify the asphalt. The properties of the asphalt cement do affect the performance of the residual asphalt on the road.
Asphalt cement is the basic ingredient of asphalt emulsions. In most cases, it makes up from 50 to 75 percent of the emulsion. Some properties of the asphalt significantly affect the finished emulsion. But there is not an exact correlation between the properties and the ability to emulsify the asphalt. The properties of the asphalt cement do affect the performance of the residual asphalt on the road.
Water is the second ingredient in an asphalt emulsion. Minerals or other materials in water can affect the production of stable emulsions. Water that is suitable for drinking may not be suitable for asphalt emulsions.
The chemical used as an emulsifier greatly influences the properties of an asphalt emulsion. The emulsifier keeps the asphalt particles in suspension and controls the breaking time. It also determines whether the emulsion is cationic or anionic (or non-ionic). Chemical compatibility of the emulsifying agent with the asphalt cement is essential for producing a stable emulsion.
The emulsion is produced by separately metering the soap and water solution and hot liquid asphalt into a colloid mill at predetermined rates and temperatures. The colloid mill shears the asphalt into microscopic particles. The size of the particles affects the physical properties of the emulsion.
Sometimes additional ingredients, including latex, polymers, acids and other additives are fed into the emulsion to further modify its physical characteristics.
Names and Classifications of Emulsions
Emulsions are classified by their ionic charge. Cationic emulsions begin with a “C.” If there is no C, the emulsion is usually an anionic. The charge is important when designing an emulsion for compatibility with certain aggregates.
Emulsions are classified by their ionic charge. Cationic emulsions begin with a “C.” If there is no C, the emulsion is usually an anionic. The charge is important when designing an emulsion for compatibility with certain aggregates.
After the charge designation, the next set of letters describes how quickly an emulsion will set or coalesce to a continuous asphalt mass. The standard terms are RS (Rapid Set), MS (Medium Set), SS (Slow Set), and QS (Quick Set).
RS emulsions break rapidly and have little or no ability to mix with an aggregate. MS emulsions are designed to mix with aggregates, and are often called mixing grade emulsions. MS emulsions are used in cold recycling, cold and warm dense-graded aggregate mixes, patch mixes and other mixes.
SS and QS Emulsions
SS emulsions are designed to work with fine aggregates to allow for maximum mixing time and extended workability. They are the most stable emulsions and can be used in dense-graded aggregate bases, slurry seals, soil stabilization, asphalt surface courses and some recycling. SS emulsions can be diluted with water to reduce their viscosity so they can be used for tack coats, fog seals and dust palliatives. SS emulsions are also used as driveway sealers.
SS emulsions are designed to work with fine aggregates to allow for maximum mixing time and extended workability. They are the most stable emulsions and can be used in dense-graded aggregate bases, slurry seals, soil stabilization, asphalt surface courses and some recycling. SS emulsions can be diluted with water to reduce their viscosity so they can be used for tack coats, fog seals and dust palliatives. SS emulsions are also used as driveway sealers.
QS emulsions work well with fine aggregates but are designed to break faster than SS emulsions. QS emulsions are used in micro-resurfacing and slurry seal designs. The quick break allows for faster opening to traffic.
High Float Emulsions
An “HF” that precedes the setting time designation indicates a High Float emulsion. HF emulsions are designed so the emulsifier forms a gel structure in the asphalt residue. The thicker asphalt film allows these emulsions to perform in a wider temperature range. High Floats are used in chip seals, cold mixes and road mixes.
An “HF” that precedes the setting time designation indicates a High Float emulsion. HF emulsions are designed so the emulsifier forms a gel structure in the asphalt residue. The thicker asphalt film allows these emulsions to perform in a wider temperature range. High Floats are used in chip seals, cold mixes and road mixes.
After the set designation, there is a series of numbers and letters that further describe the characteristics of the emulsions. The number 1 or 2 designates the viscosity of the emulsion, with the number 1 meaning lower viscosity and 2 meaning higher viscosity. If there is an h or s at the end of the name, the h indicates a harder base and the s for a softer asphalt base. For example, SS-1h is a slow setting emulsion with a lower viscosity made from a relatively hard base asphalt.
Polymers
A “P” may be added to the set designation to show the presence of polymer in the emulsion. An “L” indicates the presence of latex polymer. For example, CRS-2P is a cationic, rapid setting emulsion having a higher viscosity and containing some polymer. Polymers and latex are used to add strength, elasticity, adhesion and durability to the pavement. Polymer asphalt emulsions can be less brittle at low temperatures to resist cracking and stiffer at high temperatures to resist rutting and bleeding. Polymers permit the application of micro surfacing in wheel-path ruts and other locations where multiple stone depths are required.
A “P” may be added to the set designation to show the presence of polymer in the emulsion. An “L” indicates the presence of latex polymer. For example, CRS-2P is a cationic, rapid setting emulsion having a higher viscosity and containing some polymer. Polymers and latex are used to add strength, elasticity, adhesion and durability to the pavement. Polymer asphalt emulsions can be less brittle at low temperatures to resist cracking and stiffer at high temperatures to resist rutting and bleeding. Polymers permit the application of micro surfacing in wheel-path ruts and other locations where multiple stone depths are required.
Adaptable and Flexible
The physical properties of emulsions can be modified to optimize storage, curing, mixing, traffic return and bonding strength. Emulsions readily accept additives such as polymers, latex, fillers, anti-strips, stabilizers and other modifiers to enhance the physical properties of both the emulsion and the cured asphalt.
The physical properties of emulsions can be modified to optimize storage, curing, mixing, traffic return and bonding strength. Emulsions readily accept additives such as polymers, latex, fillers, anti-strips, stabilizers and other modifiers to enhance the physical properties of both the emulsion and the cured asphalt.
An emulsion’s charge can be positive, negative or neutral to improve compatibility with available aggregates. Emulsions can be engineered for a wide variety of conditions, such as cooler temperatures or wet or dusty conditions.
Some other attributes of asphalt emulsions include:
- Producing no or minimal hydrocarbon emissions
- Requiring no added heat for many applications
- Readily coat damp aggregate surfaces
- Producing minimal fumes
- Being ideal for remote locations where there are no hot mix plants
- Greatly reducing needs for raw materials and energy
- Being used in a variety of recycling systems
- Reducing user delay costs
- Reducing overall life-cycle costs
- Improving skid resistance
- Reducing hydroplaning and improving visibility
- Costing less than thin hot mix asphalt overlays.
The many benefits and varied types of asphalt emulsions give pavement engineers the ability to select an effective treatment for every specific road need.
The Basic Asphalt Emulsion Manual (MS-19), a joint publication of the Asphalt Institute and the Asphalt Emulsion Manufacturers Association (AEMA), is recommended for anyone needing more information on asphalt emulsions. Much of the material in this article was taken from MS-19 and from AEMA’s booklet, Asphalt Emulsions.
Skin Care Tips & Trends
What is an emulsion, and how is it different from a moisturizer? Here, we break down everything you need to know about emulsions, a hero product in the K-beauty routine.
Emulsion is a word that seems to get thrown around a lot in the K-beauty world, but no one ever seems to be able to give a straight, consistent answer of what it is or why you should use it.
I remember the first time I got a sample emulsion and I had no clue what to do with it, and to my shock, neither did the salesperson who gave it to me. However, emulsions are actually a staple in Korean skin care routines and offer a whole range of benefits. So I decided it was time to break down what an emulsion is, what it does, and how it can be used.
Emulsion Definition
What is an emulsion, and how is it different from a cream?
In a nutshell: Emulsions are lighter versions of moisturizing creams. Unlike most heavy facial creams, emulsions are typically water-based, which means they go on lighter and thinner than creams. In some cases, emulsions come in gel or almost liquid forms. On the whole, emulsions absorb into the skin much more quickly and don’t sit on top of the skin the same way some creams do.
In this photo, an emulsion is on the left and a moisturizer is on the right:
So what do emulsions do?
Emulsions offer many of the same benefits of a cream, just in a lighter formula. They’re formulated to act as a moisture lock that seals in all the hydration and benefits of your essence and serums.
Types Of Emulsions
However, many people use emulsions as a continuance of their treatment products, not just as a moisturizer.
When do you use it?
Emulsions are the in-between product between serums and creams. It’s not quite as light as a serum, but not quite as heavy as a cream. Similarly, it isn’t as concentrated as serums, but more targeted than heavy creams. And so, that’s right where it goes in the skin care routine—after serum and (optionally) before your final moisturizer. But how you use an emulsion really comes down to your skin type.
Emulsions for each skin type:
For veryoily skin
, emulsions can be an great option as your final moisturizing step before applying SPF. The fact that emulsions are lighter, water-based, and more easily absorbed make them attractive to people with oily skin as a way to get the hydration your skin needs without the weight and sheen of a cream. And if you live in a place that gets hot and humid, an emulsion can be a great option to keep your skin cool and light in the heat, while still delivering the hydration it needs.However, you should make sure that the emulsion you’re using is specially targeted for hydration to be sure your skin doesn’t get the short hand on moisture. The Dr. Oracle A-Thera Emulsion is a great option since it’s formulated with bamboo extract to hydrate the skin while balancing oils, and green tea to soothe, refresh, and depuff. It’s lighter than a moisturizer, so you get all the benefits of hydration and moisture without feeling greasy or blocking your pores. It feels thin, smooth, and water-like; with its lightweight texture, it’s perfect for oily skin types who want to hydrate without producing or provoking acne.
For combination and acne-prone skin
, you can use an emulsion to target oil, blemishes, and excess sebum. This can be done by applying an emulsion to the whole face or to specific areas, like the T-zone. The Cosrx Natural BHA Skin Returning Emulsion has natural BHAs that keep the skin clear of dead skin cells and excess sebum, while centella asiatica extract water and hyaluronic acid deliver hydration and moisture without producing more oils. You can put it on your whole face or you can use it on its own. Or, if you feel like your skin needs more moisture, you can follow it up with a cream—it’s ultimately up to you! This emulsion is more lightweight than a moisturizer but still extremely hydrating to the skin, and it soothes dry patches while keeping sebum and acne in check. This emulsion has a serum-like texture and feels light thanks to the hyaluronic acid, so it’s ideal for hydrating skin and cleaning pores without producing irritation.Normal skin types
can still obtain benefits from emulsion even if they don’t have a skin concern they want to target. The SUR.MEDIC+ Super Hyaluronic 100TM Aqua Emulsion gives skin a hydrated, dewy glow and keeps it looking bouncy and refreshed. The thin, quick-absorbing formula is both soothing and hydrating, making it perfect for year-round use; while it will hydrate in the winter, it’s still lightweight enough not to burden or stifle your skin throughout the summer. Formulated with hyaluronic acids and ceramides, it also prevents the loss of moisture to keep you looking as young as ever. Forsensitive skin
, emulsions are perfect to promote healthy, nourished skin without irritating it or penetrating deep enough to provoke inflammation and redness. The Re:P Nutrinature All in One Multitem is ideal to balance the skin’s pH, brighten, and moisturize without irritating the skin. It’s perfectly lightweight and doesn’t feel too heavy, yet the addition of niacinamide adds a reinforcing barrier to protect the skin and make it stronger while antioxidants get to work nourishing and clearing sensitive skin. This product acts as a toner, essence, and emulsion all in one, and promotes elasticity and an even skin tone and texture. It also passed the “Skin Irritation Test,” making it ideal for sensitive skin types.And if you’re in my camp and struggle with dry skin, emulsions are seriously a life-saver. When you double up on emulsion and cream, the emulsion locks in the moisture from your prior steps and the cream can be focused on just soaking into the skin and hydrating it even further. For dry skin, the Etude House Moistfull Collagen Emulsion is perfect to adhere moisture and nutrients to skin and leave it feeling hydrated and elastic. The emulsion has small particles of super collagen water and baobab water which absorb quickly into skin; it’s lightweight yet moisturizing, and with a jelly-like consistency and smooth formula, you’ll feel your skin become hydrated and refreshed immediately.
For even more moisture, you can also mix a facial oil into your emulsion since emulsions are water based and mixing in an oil means your skin gets both water and an oil-based moisture.
Bottom Line
Ever since I started using an emulsion, my skin wakes up feeling hydrated and supple, and I certainly feel it has helped my night cream be more effective. And during the winter months when my skin is fighting against freezing New York City winds, I apply the emulsion in the morning too and that extra layer of moisture really saves the day.
At the end of the day, it makes sense why emulsions have been so hard to pin down: because they have different uses and purposes for everyone.
Just like treatment products, what emulsion you use and how you use it really depends on your specific needs. But whether you’re trying to find a lighter moisturizer for humid weather, or you’re looking for another layer of moisture to keep your skin from drying out, emulsions can certainly find a way into your routine. And, take it from me, you’ll be happy once they do.
What other questions do you have about emulsions? Share them below!