There are many types of asphalt on the market, so how much do we know about the production principle of rubber asphalt? Let's take a look together.
Rubber asphalt is a modified asphalt binder material formed by first processing the original waste tire into rubber powder, then combining it according to a certain coarse and fine grading ratio, adding a variety of high polymer modifiers, and fully melting and swelling with the matrix asphalt under high temperature conditions (above 180°C) with full mixing. It is generally understood as asphalt with rubber added. Rubber asphalt has high temperature stability, low temperature flexibility, anti-aging, anti-fatigue, and water damage resistance. It is an ideal environmentally friendly pavement material and is mainly used in the stress absorption layer and surface layer of road structures.

There are three popular concepts of "rubber asphalt": "dry method" rubber asphalt, "wet method" rubber asphalt, and "asphalt depot mixing method" rubber asphalt.
(1) "Dry method" rubber asphalt is to mix rubber powder with aggregate first, and then add asphalt for mixing. This method
is to regard rubber powder as part of the aggregate, but generally the amount of rubber powder cannot be too high. This method is rarely used.
(2) "Wet method" rubber asphalt is to mix a certain amount of rubber powder with asphalt first, and react at high temperature to form a mixture with certain properties. It is currently the most widely used method for producing rubber asphalt.
(3) "Asphalt depot mixing method" refers to the mixing of waste rubber powder with hot asphalt in a refinery or asphalt depot, and then delivering it to an asphalt concrete mixing station or construction site. "Asphalt depot mixing method" can actually be regarded as a kind of "wet method" production, but its waste rubber powder usage generally does not exceed 10%, the rubber powder usage is lower, and the viscosity is lower than that of rubber asphalt ("wet method" production). The mixed mixture cannot achieve the same performance as rubber asphalt mixture.
What are the advantages of rubber asphalt compared with ordinary asphalt?
1. Anti-reflective cracks
In the rubber asphalt stress absorption layer, a high amount of rubber asphalt is strongly bonded with gravel of a single particle size to form a crack reflection structure layer about 1cm thick. Various cracks in the water-stable layer or old cement pavement will find it difficult to penetrate this layer, which can effectively curb the reflection of cracks.
2. Anti-water damage
The amount of rubber asphalt is large (2.3kg/m2), and an asphalt film of about 3mm thickness will be formed on the road surface, which can completely prevent rainwater from penetrating downward and protect the roadbed. Secondly, when paving asphalt mixture on it, the rubber asphalt on the top of the rubber asphalt stress absorption layer will melt for the second time, and after the road surface is compacted, it will fully fill the gap at the bottom of the surface mixture, thereby eliminating the possibility of water storage between layers and preventing water damage.
3. Bonding effect
Rubber asphalt has super strong viscosity. It can be adsorbed and bonded to the water-stable layer or old cement pavement very firmly, thereby playing a bonding role with the road surface.