Asphalt is everywhere.
It's in the roads we drive on, the sidewalks we cross, and even the airport runways we land on.
The History of Asphalt
Asphalt dates back as far as 2,600 B.C when the Egyptians used the composite material to waterproof their mummies. Other ancient civilizations adapted it for highways and irrigation systems.
What Is Asphalt Made Of?
Asphalt composition is around 5% asphalt cement and 95% aggregate.
Asphalt cement is a type of liquid petroleum that works as a glue to bind the aggregate together.
Aggregate varies depending on climate and other requirements. Essentially, you could define it as a bunch of small rocks.
On the lower sections of a pavement, the aggregate comprises of larger and smoother rocks. At the surface level, however, the aggregate is finer and more course.
Other additives may be included to improve the final product. For example, hydrated lime can help bond the aggregate, polymers can enhance flexibility, and tiny particles known as "fines" can extend the lifespan of the pavement.
How Is Asphalt Made?
Manufacturers create an aggregate mixture in line with specific project requirements, which they thoroughly wash and dry.
Next, they thin the asphalt cement by heating it up, adding a solvent, or emulsification in water.
Once the manufacturer has heated the aggregate and asphalt cement to the ideal temperature, the manufacturer will mix the two together using industrial mixing machines such as drums or pugmills.
The hardest part of the process is getting the temperature right. To do so, manufacturers must take into account the amount of asphalt to be transported, as well as other factors such as its thickness and compacting.
The Difference Between Hot and Cold Mix Asphalt
There are two basic types of asphalt: hot and cold.
Hot Mix Asphalt (HMA)
HMA is the most common type because its toughness makes it suitable for high demand areas such as busy roads and highways.
As the name suggests, HMA requires the manufacturer to heat both the aggregate and the asphalt cement to a significant temperature for mixing and also when being applied and compacted. The process removes moisture and increases fluidity, which makes it easier to spread.
Cold Mix Asphalt (CMA)
CMA, as you would expect, requires less heating, which equates to a lower production cost.
Quarter inch chip is used as well as proprietary oil with various additives. The result is a soft mixture from which potholes can easily be repaired all year round.
Irelands roads
The primary and secondary road network in Ireland is some 5,306km long and is made up of motorways, dual carriageways and single lane roads. Approximately 320km of the 916km motorway network is being operated by Public Private Partnerships.
Other sections are managed by Motorway Maintenance and Renewal Contract operators. Our network carries approximately 45% of the country's total road traffic and most of Ireland's freight is distributed by road.
Questions.
1. How far does asphalt date back?
2. What is asphalt composed of?
3. What works as a glue to bind the aggregate together?
4. How big is a piece of aggregate, on the path?
5. Take a picture of the path with your foot on it. (A Garmin works fine aswell.)#
Hope you enjoyed my little ramble about asphalt! Send the anwsers by message and not email please.