Research Of The Influnce To The Water Stability Of Asphalt Mixture By The Aggregates Cleanness

Since the 1990s, the development speed of Chinese freeway is very fast, the primary pavement style is the asphalt pavement of the most constructing high type highway, furthermore, the phenomenon of the early damage to asphalt pavement are very notable. In the early damage phenomenon, the key factors are water disruption, and then the brought damage phenomenons are called water damages. Water damages are embodied in deficient of the asphalt pavement water stability. So, the level of the water stability is the very important of the asphalt pavement.This dissertation aims at the practical situation of our country, references the research findings of the other countries, commences at the aspect of the anti-stripping agent by the cleaness of the aggregate and slaked lime in addition, further research of the water stability of the asphalt pavement, afford the testing foundation of the prevention and avoid measure of the asphalt pavement. The specific research aspects are: First, study the influences of the aggregate surface clay or the dust to adhere the asphalt and aggregate, contrast of the non-pollution. Second, at the instance of fine aggregates cleanness satisfy the code, change the content of dust and clay in the aggregates, study the influence of them to the asphalt mixture water stability and seek the transform relation between the different content of clay or dust and the water stability, seek the content range of dust or clay in the harsh aggregates while satisfy the water stability. Third, at the harsh aggregates cleanness satisfy the code, change the content of dust and clay in the aggregates, study the influence of them to the asphalt mixture water stability and seek the transform relation between the different content of clay or dust and the water stability, seek the content range of dust or clay in the harsh aggregates while satisfy the water stability. Forth, according to the upper values of the dust content range in the harsh or fine aggregates which have mentioned above to mix the asphalt mixture, adopt the strategy of anti strip, the anti-stripping agent is slaked lime, from the different contents of the additional slaked lime, survey the change of the asphalt mixture water stability, seek the quantity of the additional slaked lime while the water stability is meet the demand.This dissertation has abundant experimental research of this issue; it is include the foundation tests, the tests of aggregate cleanness and the tests of mixture water stability. The foundation tests are mainly to test the physical and chemical performance index, they are include the penetration, softening point, ductility and density of the asphalt, the density test of the harsh aggregate, fine aggregate and the mineral powder addition, and the test sieving of slaked lime, etc. The test of aggregate cleanness and the harsh aggregates adoption is water clean method, the fine aggregates adoption is sieve clean and sand equivalent weight methods. The test of water stability is aim at the relax asphalt mixture and compact asphalt mixture. The water stability test of the relax asphalt mixture is primary to assess the adherence, this research adopted the test method is water seasoning. The water stability test of the compact asphalt mixture adopted the water seasoning Marshall Test and frost thawing split test.According to the abundant indoor test and analysis: the water sensitivity of asphalt mixture which consist with the dirty aggregates is higher than the clean one; for the mineral aggregate of the intermediate rock and the gradation style is the AC-13 asphalt mixture, at the instance of the same clay content of the harsh and fine aggregates, the water stability influence of harsh aggregates is lower than the fine aggregates; for the water seasoning Marshall Test, by the rate of MS0 to reflect the water stability singly is deficient; at the instance of reach the same physical index, keep the cleanness of the aggregates could economize the dosage of the asphalt; at the instance of the aggregates is polluted by the dust, the slaked lime could improve the water stability of the asphalt mixture, therefore, there is a optimum mix quantity, at the same of the using optimum asphalt quantity, the improve effect will be changed when the quantity is higher or lower. According to this research result, the cleanness of the aggregates is very important of the asphalt mixture, particularly the cleanness of the fine aggregates. It is not only making the water stability of the asphalt mixture satisfy the demand, but also could insure the early using character of the asphalt pavement. Because, the adherence between the asphalt and the aggregates will be damaged by the clays, and the initial adherent is very important to the asphalt mixture.