Bitumen – Asphalt

Bitumen – Asphalt | Asphalt, also known as bitumen, is a petroleum-based liquid or semi-solid that is sticky, black, and highly viscous. It is classified as a pitch and can be found in natural deposits or as a refined product. The term asphaltum was also used before the twentieth century. The word o ásphaltos comes from the Ancient Greek o ásphaltos. The Pitch Lake in southwest Trinidad (Antilles island off the northeastern coast of Venezuela) is home to the world’s largest natural deposit of asphalt, estimated to contain 10 million tonnes.

Asphalt is primarily used in road construction (70 percent), where it is mixed with aggregate particles as a glue or binder to create asphalt concrete. Its other main applications include bituminous waterproofing products, such as roofing felt and flat roof sealing.


Although there is regional variation in which term is most commonly used, the terms “asphalt” and “bitumen” are often used interchangeably in material sciences and engineering to mean both natural and manufactured forms of the substance.

The term “bitumen” is used by geologists all over the world to describe the naturally occurring material. In much of the world, “bitumen” is the most common term for the manufactured material, which is a refined residue from the distillation process of selected crude oils; however, “asphalt” is more commonly used in American English.


In the United States, the terms “liquid asphalt,” “asphalt binder,” and “asphalt cement” are used to avoid confusion. Although tar is a different material, various forms of asphalt are sometimes referred to as “tar,” as in the name of the La Brea Tar Pits.

The term “crude bitumen” is sometimes used to describe naturally occurring asphalt. It has a viscosity similar to cold molasses, and it is sometimes referred to as “refined bitumen” because it is obtained from fractional distillation of crude oil boiling at 525 °C (977 °F). The Athabasca oil sands, which cover 142,000 square kilometres (55,000 square miles), an area larger than England, contain the majority of the world’s natural asphalt reserves.

Because the properties of asphalt change with temperature, there is a specific range in which viscosity allows for adequate compaction by providing lubrication between particles during the compaction process. Low temperatures prevent aggregate particles from moving, making it impossible to achieve the required density. Some of the properties of asphalt can be reproduced using computer simulations of simplified model systems.

Since around 6000 B.C., bitumen and bituminous materials have been known and used in construction projects. Asphalts were used in boat construction as a cement to hold stonework together and as a waterproofing in pools and baths. Paving streets and palace floors was done with a mixture of asphalt and stand.


Asphalt was used by the Egyptians in the mummification process and as a building material. The Greeks and Romans used asphalt not only as a building material, but also as a military weapon by burning it. Natural asphalt formed when crude petroleum oils rose to the earth’s surface and formed pools was used by these ancient civilizations. The sun and wind blew away the lighter oils and gases, leaving a thick residue behind. Asphalt was present in the residue, along with impurities such as water and soil. Cementing and waterproofing materials were made using the crude distillation process.

Classification of Bitumen

Er. Md. Shahin Akhter

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Md Shahin Akhter is a Civil Engineer from MIT and has more than 5 years of experience in Civil Engineering and Construction Department. Md Shahin Akhter is Civil Engineer in Nagar Parishad (Municipal Council), Supaul. He is Webmaster and Founder at ProCivilEngineer.com Civil Engineering Website.