Tarmac, full name tarmacadam, is a popular driveway option because it is strong and hard-wearing and can easily take the weight of heavy vehicles without getting damaged. Many people use the “tarmac” to refer to a few similar driveway surfacing options, including bitmac and asphalt. We’ll be covering all these different options here so that you can get a feel for the different types of tarmac that are available.
Quick History Of Tarmac
Back in 1820, John MacAdam invented a new road surfacing method that involved placing gravel on top of the surface. He named this process macadam, and it is still very much in use today. In 1902, this process was refined by Edgar Purnell Hooley by adding an extra tar layer and was patented as tarmacadam, which is now usually shortened to tarmac.
Tarmac is quick to install, relatively low-cost compared to other surfacing solutions, durable, weather-resistant, and easy to maintain. On the downsides, it is vulnerable to UV damage from the sun’s rays which can make it brittle and lead to cracks and there is the potential for weeds, moss, and algae to take hold if it isn’t cared for.
Open-graded tarmac
Open-graded tarmac has fewer stones embedded into it, which makes it semi-permeable. Lots of homeowners are looking for a permeable driveway surface because with these, the water is able to soak through the surface and into the ground below. This reduces the chance of water building up on your driveway.
Close-graded tarmac
Compared to the open-graded tarmac, close-graded has a much higher concentration of small stones. This does mean that it isn’t a permeable surface, so you will need to look into other drainage solutions, but many people prefer it because it gives a more uniform and smooth finish.
Bitmac
Bitmac, full name bitumen macadam, uses the same process invented by John MacAdam but, instead of using natural tar as the binding agent, it uses bitumen which is refined from crude oil. Since petroleum is distilled more widely, bitumen is readily available, so bitmac is usually the material of choice over “true” tarmac.
Bitmac is also less resistant to petrol and oil spills than tarmac made with tar. These types of spills can degrade tarmac which can make it brittle and prone to cracking and damage, but they don’t have the same effect on bitmac. You are unlikely to come across tarmac that is made with natural tar these days, and any tarmac you see will almost certainly be bitmac.
Asphalt
Asphalt is a very different material to either tarmac or bitmac, and it isn’t created using the same macadam process. It is, however, often placed under the same umbrella as tarmac when choosing a surfacing option because it can appear to be strikingly similar.
Like bitmac, asphalt uses bitumen as a binding agent, but the process and make-up of the aggregates are different. In the USA, when people speak about asphalt they are referring to bitumen itself, which can be confusing. But in the UK, asphalt is used to asphalt concrete as a surfacing option.
Asphalt is commonly used on roads, playgrounds, and car parks, but is also a great option for driveways. It is both strong and flexible, and it is very easy to repair. If you are concerned about the environment, then asphalt can be a great choice for your driveway because it is 100% recyclable (unlike tarmac or bitmac).
Design options
Some people discount tarmac as a potential driveway surfacing option because they think that it won’t look good. While it is true that the standard black option can look a little industrial, many people don’t realize that you can actually get tarmac in a variety of different colour options. You can also edge your tarmac with stones or bricks to give it a nice finish.
Where is tarmac used?
All the different types of tarmac lend themselves well to surfaces that will face a lot of traffic, particularly from cars and other vehicles. So you will often see tarmac on roads, car parks, and cycle paths. It is the perfect surface for these situations because it is smooth enough not to cause any damage to tyres, but it is also hard-wearing enough to take the daily weight and wear-and-tear associated with traffic.
You can often see it also used in playgrounds because it is hard-wearing, but also safe for children because there aren’t any sharp stones sticking out that could hurt them if they fall. With that being said, many playgrounds are moving away from tarmac because it can get very hot to the touch in sunny and warm weather.
In home situations, you will most often see tarmac used for driveways, and this is because of the exact same reasons for its use on roads, car parks, and cycle paths. It will be able to handle the weight of your vehicle without causing it any damage. It is also a quiet surface, so your vehicle won’t make too much noise when you are parking up (which your neighbours may well be thankful for).
Unfortunately, partly because of its association with industrial areas such as roads and car parks, many homeowners turn to solutions other than tarmac for their driveways. But, as we have mentioned, there are lots of options nowadays to make your tarmac driveway truly your own.
You are unlikely to see tarmac used for other outdoor areas like patios because it gets so hot in the sun (although this risk may be lessened if you make a colour choice other than black).
The bottom line
Tarmac (plus bitmac and asphalt) is a very popular surfacing option for areas that will be used for vehicles, which makes it a great choice for driveways. It can bear the heavy loads associated with vehicles, and it is hard-wearing, durable, and easy to maintain. There is quite a variety when it comes to different types of tarmac, so it is always a good idea to talk through your options with the contractor who will be working with your driveway so that you can find the perfect solution for your needs.
Now you have been given the knowledge to tell your open-graded from your asphalt. Take some time to read more from our ever growing Blog section!
