Rutting is a unique failure form of asphalt concrete pavement. It is a permanent deformation under the combined action of repeated driving load and climate (high temperature), which is manifested as a longitudinal band groove along the wheel track. In severe cases, there will be protruding deformation on both sides of the rut, which will make the pavement performance worse. Rutting has always been one of the main diseases of asphalt concrete pavement. In the late 1970s, a survey was conducted by state highway bureaus in the United States. Among the 44 main roads surveyed, there are 13 roads with rutting damage, accounting for 29.5% of the total surveyed. More than 80% of the reasons for highway pavement maintenance and overlay in Japan are caused by rutting. For expressways in our province, the road traffic volume is growing very rapidly, often far exceeding the expected growth rate. At the same time, the proportion of heavy vehicles on the expressway is increasing, and the phenomenon of vehicle overload and overrun is very common. This traffic situation has a very serious destructive effect on the pavement, especially leading to rutting in the early stage of the pavement. Facts also show that rutting has become a common type of pavement disease after water damage in the maintenance of asphalt pavement of expressways that have been completed and opened to traffic in our province.

1, types and characteristics of rutting

According to the formation mechanism, rutting of asphalt concrete pavement can be generally divided into the following four categories:

(1) Wear-type rutting: This kind of rutting is caused by tire wear on the road surface. In China, it usually happens when the vehicle has a flat tire and the steel wheel directly acts on the asphalt concrete pavement. Generally speaking, these ruts do not need special maintenance.

(2) Compressive rutting: This rutting is mainly caused by the compressive deformation of asphalt concrete pavement itself. The rutting forms a "V" shape with a depth of 5 ~ 10 mm, which has little influence on road traffic.

(3) Structural rutting: This rutting is mainly caused by unreasonable pavement structure design, or poor compaction or integrity of structural layers, especially insufficient bearing capacity of subgrade. This kind of rut is often wide in the lateral direction, with no obvious uplift on both sides, and a U-shaped (concave) section, often accompanied by cracks, which will not be stable in the short term. With the passage of time, rutting depth and other related pavement damage will continue to intensify.

(4) Rheological rutting: This rutting is mainly caused by insufficient high-temperature stability of asphalt concrete or serious overloading of trucks and shear deformation of asphalt concrete. This kind of rut has obvious uplift phenomenon, and the whole rut section forms a "W" shape with a depth of 20 ~ 50 mm In severe cases, a large area of loose damage will occur locally, and the running and jumping are obvious.

In China, because semi-rigid base is widely used in asphalt pavement of high-grade highway, most ruts belong to flowing ruts and compression ruts. For compression rutting, because the rutting is shallow, it does not affect the use, and generally no special treatment is needed. When it is serious, the rut can be leveled by hot-mixed asphalt concrete to achieve the purpose of restoring pavement performance. At present, there is no economical and effective maintenance technology for mobile rutting, usually milling, asphalt concrete pavement resurfacing, or thermal regeneration maintenance technology, but the general mobile rutting lasts for a long time (up to several kilometers), involving the whole pavement. The use of these technologies has high maintenance cost and great influence on traffic, so it needs special caution in large-scale application.

2 Road rutting treatment construction method

(1) First, conduct a comprehensive survey on the road conditions of the whole line, and determine the road sections that need to be rutted separately according to the road conditions.

(2) Set up safety signs, construction signs and warning lines with road signs to ensure safe and smooth traffic.

(3) For the rutting of the road surface, use a paving truck (with a V-shaped groove) for rutting filling construction. The middle of the rut is slightly higher than the original road surface according to the situation, and the excess residue is removed.

(4) After a certain period of time, open the traffic. (13) Initial maintenance: ① After the mixture is paved, all vehicles and pedestrians are prohibited from passing before the traffic is opened. ② After the mixture meets the requirements of open traffic, the traffic should be opened as soon as possible.