Tarmac, asphalt and bitumen are three very popular construction materials used all over the world. The problem is that the majority of people cannot tell the difference between them. To the untrained eye, they may seem similar in their physical appearance but they are different as each has its properties under various conditions. Hence the need to differentiate them from one another. In some countries, the words may be used interchangeably or in relation to the primary functions. In some countries, tarmac may be used in relation to runways and asphalt in relation to road constructions.
Tarmac
Tarmacadam is a road surfacing material that was pioneered by John McAdam in the 1820s. Tarmac was patented by Edgar Hooley, an English inventor in 1902. McAdam invented the technique of joining smaller aggregates together using tar. However, as petroleum production became widespread, bitumen became available in large quantities and it was used instead of tar. Tarmac is the short form of the word tarmacadam. Edgar Hooley’s technique was to mechanically mix tar with the aggregate prior to application, then compacting it with a heavy roller. The tar was also modified using resin, cement and pitch. Today the word tarmac is used for asphalt road surfaces.
Asphalt
Asphalt concrete is also known as blacktop. Today, it is the most used material in the paving and surfacing industry. It contains a binder, aggregate and filler mixture just like tarmac. Asphalt, however, can be scraped from older surfaces and reprocessed. This makes it more environmentally friendly. Asphalt concrete consists of bitumen which is a semi-liquid sticky material which is used as a binder for sand and rock aggregates. Asphalt was in the ancient times used for waterproofing and its adhesive properties. Asphalts is also available in different types and each type has its qualities.
Bitumen
Bitumen is a semisolid form of petroleum by-product. It can also occur naturally in places that had ancient algae or remains that were deposited mostly at the bottom of the lakes and oceans and buried under high pressure and temperatures higher than fifty degrees, such remains are then transformed into crude petroleum or bitumen. Bitumen is mostly used in asphalt concrete where it is used as a binder. It is also used in bituminous waterproofing products, sealing flat roofing structures and producing roofing felt. Bitumen is also called asphalt in some countries making it more confusing.
Difference between tarmac and asphalt
Tarmacadam has since developed from the earlier days from using tar to using bitumen. However, the use of asphalt has been more popular in recent years, here are some of the most common differences.
l Tarmac is not reusable. Asphalt, on the other hand, can be scrapped off and reprocessed which makes it more environmentally friendlier than tarmac
l Tarmac has larger aggregates than asphalt. Asphalt has a smoother surface which increases tyre grip. This is because there is more surface in contact with the tyre.
l Asphalt is more flexible than tarmac and it can take stress without cracking
Tarmac asphalt are the most preferred materials for paving road surfaces as they are long lasting, cheaper and are easy to install. You should, however, consult a professional before you decide the best option for your driveway.
