| Cold patch asphalt mixture is a new pavement repair material, which isn’t limited by climate and weather conditions. In recent years, this material get the favour of more and more pavement maintenance department, with the advantages of using with the check, energy saving and environmental protection. The overall price of foreign cold patch asphalt mixture products is higher than domestic prices. The products of internal, which due to lack of cold patch asphalt mixture road performance test methods and evaluation index and lead to uneven product quality, generally have low initial strength, rutting resistance poor, poor water stability, short service life and other issues. These problems greatly restrict the cold patch asphalt mixture application in road maintenance industry and don’t conducive to improving traffic conditions. So research cold patch asphalt with low price and good performance is very necessary.Based on the depth analysis of cold patch asphalt mixture material in the formation principle and mixture strength formation mechanism, this paper used a variety of mineral clays to modify asphalt and the cold patch asphalt mixture was prepared with three kinds of diluent. This thesis systematically studied the pavement performance of cold patching asphalt mixture by Marshall experiment, Marshall immersion test, low temperature workability test, freeze-thaw splitting test, rutting test and other laboratory tests. Experiments showed that the diluent have some influence on cold patch asphalt mixture, Marshall strength and low temperature workability. Heavy oil can be added to increase the strength of the Marshall, but too much amount of heavy oil will affect the mixture cold workability. Therefore, this experiment adopts the diesel-heavy oil as diluent. The cold patch asphalt mixture which was prepared in the laboratory has high road performance, such as forming strength, water stability and high temperature stability. Through the infrared, scanning electron microscopy and thermogravimetry-differential thermal analysis to carry on to the material and the microscopic analysis showed that between the metal and mineral clay is physical change process and after adding mineral clay found no obvious delamination phenomenon between asphalt and mineral clay, modified asphalt the decomposition temperature and the ratio of the weight loss did not change substantially, but asphalt heat absorption rate, as well as the location of the endothermic peak changed.After a number of tests, we made actual road repair in the cold winter season and presented cold patch asphalt mixture construction techniques and precautions. Later observation results showed that the self-developed cold patch asphalt mixture had low price, good performance, and good effect repair features, compared with similar products on the market. So the self-developed cold patch asphalt mixture is a kind of good performance of road maintenance materials that can be widely applied. |
