3 general types of asphalt for road stabilization

History of Asphalt and Road Construction

Before installing geotextile for road stabilization, it is better to get more familiar with road construction and the difference between concrete asphalt and bitumen asphalt and the structure of geotextile.

The path that connects the two places is called a road, and this type of road dates back to Mesopotamia (modern-day Iraq) around 2200 BC. The peak of modern road construction in Iran dates back to the time of Reza Shah, which means that most of the old roads are now about 100 years old and new technologies must be used to build new roads and repair old roads. Roads are designed and built based on the use and passing of heavy and light vehicles and environmental factors.

In the construction of roads, we should pay attention to the factors such as water infiltration, groundwater, canals and infrastructure under the road, ambient temperature, and the contraction and expansion of asphalt in different seasons, and so on.

Three Types of Asphalt for Road Stabilization

Asphalt or Asphalt concrete is a composite or combined material that is commonly used to pave roads, parking lots, airports, as well as the core of soil dams. The history of using this type of asphalt dates back to the early twentieth century, which is classified into three main categories:

  1. hot asphalt concrete
  2. protective asphalt concrete
  3. cold asphalt concrete

1. Hot Asphalt Concrete

Which is the most familiar type of asphalt, ie the same bitumen asphalt and hot stone materials that are spread hot during work. In this type, more than 90% of asphalt mixture is usually made of stone materials.

hot asphalt concrete

Hot asphalt is also classified as different types such as Topka surface asphalt, liner asphalt, asphalt sand, porous asphalt and bitumen asphalt with geotextile installation, which is more common in IRAN.

2. Protective Asphalt Concrete

Protective asphalt is a type of paving with a maximum thickness of 255 mm, which is used for the surface of sandy or asphalt roads. In protective asphalts, soluble bitumens, bitumens or pure bitumens with low humidity are used. Protective asphalts are used to make the road surface impermeable, prevent dust, increase the abrasion and slippery roads, as well as temporarily improve the existing asphalt and concrete procedures.

protective asphalt concrete

This type of procedure is very cost-effective compared to hot asphalt due to its speed and ease of implementation and the limited need for asphalt machinery and equipment. Types of protective asphalts include single-layer, multi-layer, cold-rolled protective asphalt, primer type, single coat type, silket type, Red Mix type protective mix, asphalt concrete advantages.

3. Cold Asphalt Concrete

Cold asphalt is obtained by mixing stone materials with soluble bitumen or emulsion at ambient temperature and is divided into two categories: factory cold asphalt and on-site cold mix asphalt. Cold asphalt is used by installing geotextiles in all pavement layers, provided that all design criteria or categories along with traffic restrictions of the route are observed.

cold asphalt concrete

Advantages and Disadvantages of Asphalt Concrete for Road Stabilization

Currently, two types of hot bitumen asphalt and cold concrete asphalt are used to build roads and paths, each of which has its advantages and disadvantages, for example:

Advantages of bitumen asphalt : life-Time with quality materials is up to 10 years

Disadvantages of bitumen asphalt : possibility of bitumen leakage, high water absorption,

Advantages of concrete asphalt: Life-Time with quality materials up to 30 years, suitable for sloping areas, suitable for heavy vehicle traffic, beauty and environmental protection, reducing maintenance and repair costs, low water absorption, cold and heat resistant Intense, high run speed, improved drainage, light reflection at night

Disadvantages of concrete asphalt : the need for advanced and expensive machines, the need for high accuracy in its production and execution, the production of high noise during work, the presence of expansion joints, more difficult repairs and operations in concrete pavement.

concrete asphalt on roads

Of course, the usage of concrete asphalt on roads instead of bitumen asphalt has been common in various countries for many years, especially in developed countries, but in Iran people, contractors and construction officials are strangers to it and are the only few companies that use this type of asphalt in Iran. They use that the Isfahan-Shiraz freeway is of this category, and to improve the life of the road, the geotextile of Zarif Mosour Company has been used.

Learn more : Geotextile Installation Guide In Road Stabilization

Learn more : Geotextile of Zarif Mosavar industrial Group

Learn more : Application Of Nonwoven Geotextiles For Improving Asphalt And Roads

Use and passage of heavy and light vehicles and environmental factors, water infiltration, groundwater, canals and infrastructure under the road, ambient temperature and shrinkage and expansion of asphalt in different seasons, etc.

Asphalt is the last layer of asphalt concrete that is in direct contact with traffic loads and atmospheric factors. The surface asphalt is designed and executed in such a way that it can withstand the incoming loads and withstand the effects of water, frost and temperature changes.

This layer of asphalt concrete is located between the top layer and the base layer of bitumen and in the absence of bitumen base layer, between the top layer and the base layer of crushed stone.

This layer as the first layer of asphalt concrete pavement can be placed directly on the foundation layer. The bitumen base has a larger granulation and the amount of bitumen is less than the asphalt lining and surface.

Asphalt sand is made by mixing crushed sand or washed natural sand or a mixture of these two with bitumen. Asphalt sand can be spread and applied in layers with a thickness of at least 15 mm and more. Asphalt sand is also used as a leveling layer for old asphalts (before coating).

This asphalt is prepared from a mixture of modified pure bitumen with 100% broken stone materials with open granulation in a hot asphalt factory and is applied with a thickness of about 25 to 40 mm. The empty space of this hot asphalt after being hit on the road surface is about 20%. This layer is not part of the pavement system and can not be used as an alternative layer to the main procedure.