How hot is asphalt? There are several types of flexible asphalt pavement, which differ by the type of coating existing in its structure. Therefore, we will now analyze the last layer of the floor: the covering.
Asphalt coating components
All asphalt coatings are composed of associations of asphalt binders and aggregates. We will now see what constitutes each of them.
Did you know that asphalt is a type of binder and not a type of coating and that, differently from what is thought, its use is not restricted only to paving?
Asphalt is a mixture of hydrocarbons naturally derived from petroleum. The main component is bitumen, which may contain other materials, such as oxygen, nitrogen, and sulfur, in a small proportion.
Due to its properties, it is the most widely used type of binder in the world. Among these properties, we can highlight the high adhesive strength, impermeability, and low chemical reactivity.
As we already know, aggregate is defined as material without a defined shape or volume, usually inert, of suitable dimensions and properties for the production of mortars and concrete.
The novelty is that, as in civil construction, crushed stone is also widely used in paving.
However, the selection of aggregates for use in asphalt coatings depends on their availability, cost, quality, and type of application.
Asphalt coating types
It is worth mentioning that the most used type of asphalt coating is the pre-mixed hot coating. The most used asphalt mixture is Asphalt Concrete, also known as Hot Machined Bituminous Concrete of dense graduation, which consists of aggregates of various sizes and asphalt binder, heated according to the desired viscosity.
Bituminous surface treatment
In this type of coating, the asphalt binder’s penetration occurs in an inverted manner, that is, from the bottom up.
In this way, the coating is carried out through one or more bituminous material applications, following the same number of applications, spreading and compression of layers of aggregates.
In this type of coating, the binder’s application occurs opposite to the surface treatment, from top to bottom.
In this case, there is the spreading and compacting of layers of aggregates, each layer being subjected to an application of bituminous material.
In this case, the aggregate is pre-wrapped with the bituminous material before compression, usually in asphalt plants.
This mixture is made at high temperatures, around 100 ° C, and the transport and spreading of the coating must also be done at high temperatures.
In the cold premixed coating, the process takes place in a similar way to the hot premixed coating. The main difference is that the mixing can be done at room temperature.