6 CHARACTERISTIC PROPERTIES OF BITUMEN

Bitumen is defined as “a viscous liquid, or a solid, consisting essentially of hydrocarbons and their derivatives, which is soluble in trichloro-ethylene and is largely non-volatile and slowly dissociates when heated. slowly softens”. It is black or gray in color and has waterproofing and adhesive properties. It is obtained from petroleum by refinery processes, and is also found as natural deposits or as a component of naturally occurring asphalt, in which it is associated with mineral mats.

Bitumen has the following five distinctive properties.

  1. bitumen adheres
  2. bitumen is elastic
  3. bitumen is plastic
  4. bitumen is viscoelastic
  5. bitumen era
  6. Bitumen Hardens

1. bitumen adheres

Bitumen has excellent adhesive properties provided the conditions are favorable. However adhesion in the presence of water creates some problems. Most of the aggregates used in road construction have a weak negative charge on the surface. Bitumen aggregate bonding is caused by weak dispersion force. Water is highly polar and therefore strongly binds to aggregates displacing the bituminous coating.

2. bitumen is elastic

When one takes a thread of bitumen from a sample and stretches or stretches it, it has the potential to eventually return to a length close to its original length. For some bitumen this process may take longer than for others. This property is known as the elastic character of bitumen.

3. bitumen is plastic

When the temperature is raised, as well as when a load is applied to the bitumen, the bitumen will flow, but will not return to its original state when the load is removed. This condition is called plastic behavior. Applying a load means that you put a load on the bitumen so that it is subjected to stress. This can be done in the final position of bitumen in a laboratory or on the road and is done to assess the response of bitumen to the load.

4. bitumen is viscoelastic

Bitumen has a viscoelastic character. Its behavior can be viscous or elastic depending on the temperature or the load. At higher temperatures, more flux or plastic behavior occurs, whereas at lower temperatures and shorter periods of load, bitumen becomes hard and elastic. At intermediate temperatures it is a combination of both.

5. bitumen era

Aging refers to the change in the properties of bitumen over time due to external conditions. These changes are visible as cracks or crumbling areas. When bitumen is exposed to atmospheric conditions, the bitumen molecules react with oxygen, resulting in changes in the structure and composition of the bitumen. This process of combination with oxygen is called oxidationBitumen becomes brittle and hard and changes color from dark brown or black to brown. This change is usually called oxidative hardening or age hardening, This form of aging occurs more often in warmer climates or in warmer climates, making older pavements crack more easily. This condition can also occur if the surface film of the bitumen is thin, or insufficient compaction has occurred during manufacturing.

Read also: Factors affecting the aging of bitumen

6. Bitumen Hardens

Exposure to ultraviolet (UV) rays and evaporation of volatile compounds can cause bitumen hardening. A volatile substance is a material that can very quickly turn into a gas. There are two types of hardening:

  • physical hardening
  • exudative hardening

Physical hardening occurs when waxy crystals form in bitumen structures, or when asphaltene agglomerates clump together. This situation can be reversed if the temperature is raised.


Exudative hardening occurs due to the absorption of oily components in bitumen.


Er. Mukesh Kumar

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Er. Mukesh Kumar is Editor in Chief and Co-Funder at ProCivilEngineer.com Civil Engineering Website. Mukesh Kumar is a Bachelor in Civil Engineering From MIT. He has work experience in Highway Construction, Bridge Construction, Railway Steel Girder work, Under box culvert construction, Retaining wall construction. He was a lecturer in a Engineering college for more than 6 years.