Rubber powder is an abbreviation for rubber powder. It is generally processed from waste tires. Commonly used processing methods are: normal temperature crushing method, freezing method, and normal temperature chemical method. Rubber powder is widely used in sports plastic playgrounds, playgrounds, rubber floor tiles, waterproof coiled materials, waterproof coatings, road modified asphalt, rubber products and other fields.
The application of rubber powder in road construction, the earliest international literature on rubber asphalt was found in the British patent in 1843. In the modern sense, rubber asphalt mixture first appeared in the United States in the 1940s and 1960s. The American Rubber Recycling Company first produced RamflexTM rubber powder asphalt mixture in the 1940s by using the dry-mix production process, while American experts first adopted the wet-mix production process and produced OverflexTM rubber asphalt mixture in the 1960s. Internationally, the technical fields of rubber powder used on highways mainly include: rubber asphalt, rubber powder modified asphalt concrete, rubber powder modified emulsified asphalt, the use of rubber powder particles in the base layer, and rubber powder drainage materials.
Rubber asphalt
Incorporating rubber powder into asphalt to make rubber asphalt is the most common application of rubber powder in the highway industry. It has a history of more than 150 years since it was produced. Since the chemical components of rubber powder and asphalt are not exactly the same, and both have strong inertness, the mixing of rubber powder and asphalt is mainly a swelling reaction, which is not only a simple physical filling, but also a chemical reaction. In a state where the two coexist, the product is a blending system of rubber powder and asphalt, which improves the physical and chemical properties of asphalt. The properties of rubber powder, the properties of asphalt, and the blending method between the two may affect the performance of rubber asphalt. However, due to the complex interaction between rubber powder and asphalt, there are still many experts who have done special research on it. In addition to the production of rubber asphalt concrete, rubber asphalt is also used for stress absorbing layer (SAM), stress absorbing intermediate layer (SAMI), crushed stone seal layer (CHIPSEAL), road waterproof material (TACKCOAT) and joint filler. And in these respects, the usage of asphalt rubber even exceeds the usage of asphalt rubber concrete.
Rubber powder asphalt concrete
Rubber powder asphalt concrete includes asphalt concrete produced by dry and wet methods. Wet method refers to the process of mixing or mixing rubber powder or particles with asphalt to make rubber asphalt, which is used as a binder and then mixed with mineral materials. The dry method refers to the process in which the rubber powder and the aggregate are first mixed and blended and then sprayed into the asphalt mixing mixture. The generalized wet method also includes the rubber powder modified emulsified asphalt used for the slurry seal, and the generalized dry method also includes the process of spreading the asphalt mixture and then spreading the rubber particles together. In the international arena, the wet method generally refers to rubber asphalt concrete, and the dry method mainly refers to rubber powder modified asphalt concrete.
In practical applications, the main differences between the two are:
(1) The amount of rubber powder used in the rubber powder modified asphalt concrete (usually 210%~5% of the weight of the mineral aggregate) is that of the rubber asphalt concrete (20% of the binder weight, 115% of the mineral weight) 2~4 Times
(2) The method of adding rubber powder to the rubber powder modified asphalt concrete is simple. The rubber powder enters from the mineral material port and the dosage is easy to control; the rubber powder of rubber asphalt concrete should be mixed with the asphalt in advance, pre-processed and stored, and the use cost is high. ；
(3) The rubber powder (116~614mm) used in rubber powder modified asphalt concrete is generally coarser than the rubber powder used in rubber asphalt concrete.
At the same time, based on the use effects of rubber powder modified asphalt at home and abroad, the technical performance of rubber powder modified asphalt is much higher than that of ordinary asphalt, and has similar road performance compared with SBS modified asphalt. The research results of this subject are summarized and combined It can be concluded from practice at home and abroad that powder-modified asphalt is a high-performance, low-cost, environmentally-friendly new road material. The pavement paved with powder-modified asphalt has the following advantages:
(1) Slow down the aging of asphalt pavement, which can extend the life by 1-3 times compared with ordinary pavement (foreign data);
(2) Reduce traffic noise pollution by 2-5 decibels;
(3) Increase the flexibility of the road surface, so that no dust will be raised when the vehicle is driving;
(4) It can effectively shorten the braking distance of the vehicle, reduce road reflections, and improve the driving safety factor of the vehicle;
(5) Strong adhesion, abrasion resistance and water peeling resistance are greatly improved. Research data shows that the abrasion life of rubber powder modified asphalt pavement is 2-3 times that of ordinary pavement, reducing road maintenance costs by 30-50%;
(6) The tear resistance in winter and the melting resistance in summer are increased by 40% (no crack at -28°C and no soft at high temperature at 80°C).
From many successful application experiences, it can be seen that the use of rubber powder in road construction projects has an obvious effect on environmental protection and public welfare. It can not only solve the social problems caused by waste tires, but also can thin the road surface, extend the service life of the road surface, delay reflection cracks, and reduce Driving noise, with excellent winter flexibility, etc., is one of the effective ways to solve the problems of heavy-load traffic and early damage that our country is currently facing. For highway construction, construction investment can also be saved. For our country, with limited financial and material resources, building a high-quality asphalt pavement is a good alternative. It has good application prospects and should be promoted vigorously.
