Asphalt, bitumen and tarmac, the three most popular road surfacing materials are indeed quite difficult to tell apart at first glance. However, the nature of these three materials vary drastically, so it is important that you understand their characteristics before you decide on the best surface for your road, driveway or parking area.
Bitumen describes a naturally occurring material (referred to as tar or “crude bitumen”) as well as man-made by-product of petrochemical industry. The streets of Baghdad were paved with tar as far back as 8th century AD. It was also used as seal for roofing shingles and to seal the hulls of ships and boats. Bitumen is normally black. Bitumen or tar is 100% recyclable and thereby environmentally friendly. Tar is susceptible to temperature changes. It becomes brittle in cold weather and very soft in hot weather.
Asphalt, in its liquid form sometimes also referred to as tar, is produced in a plant that heats bitumen and mixes it with aggregate (sand, gravel etc.) into a composite mix sometimes referred to as asphalt concrete. Asphalt results in a smoother and more durable surface than a bitumen-sealed road. Asphalt is mainly used for the paving of road surfaces, car parks, tennis courts and play areas. Asphalt surfaces have a better durability and resistance to weathering than tars. Asphalt is generally a bit more expensive than tar.
Tarmac, short for tarmacadam, is a road surface paving material that was patented in 1901 by Edgar Purnell Hooley. It is a mixture of tar, modified with small amounts of Portland cement, pitch and resin which is mixed mechanically and heated before laying it down. The mixture is then covered with gravel or stone chips and then compacted with a steamroller.