Research On Friable Damage Of Asphalt Pavement

There are two types of performance for the friable destruction of asphalt pavement. First the insufficient of water stability can easily lead to the friable destruction of asphalt pavement. Second, lack of capacity of its own role in the resistance of twist-rub action by the automobile tires will lead to friable destruction of asphalt pavement, too. However, the study of loose destruction is limited to the insufficient water stability at present. There is no correct understanding for the friable destruction of asphalt pavement caused by the twist-rub action. So far, there is still lack of effective and comprehensive methods of prevention, assessment and management for friable destruction. The systematic study for the friable destruction will have important practical significance.In this paper the failure mechanism for the friable destruction of asphalt pavement were investigated. The coupled water-loading action will make the asphalt had good internal cement capacity gradually weakened and even lost, which can lead to the loose damage of the interior or the surface of asphalt pavement. Adhesion damage is an important failure mode for this type. The friable destruction of asphalt pavement caused by the twist-rub action is mainly because of lack of asphalt initial capacity of anti-loose, tire powerful "twist" rub role makes the surface and inner embedded squeeze each other between aggregate disturbance, destroyed the cementation, which can lead to the loose damage of the interior or the surface of asphalt pavement. It has two failure patterns : the cohesive damage and fracture damage.In order to have a good distinction and evaluation for the anti-loose performance of different asphalt mixture, this paper made some improvement for the Kentucky flying test. This test can evaluate the aeration of asphalt mixture intuitively at present. This paper suggest, on the basis of the original conventional flying test, increasing ten steel balls to strengthen the distinction of the anti-loose performance of different asphalt mixture and diminish the discreteness of test result. Based on the imitation of actual tire twist-rub action on asphalt pavement, this study developed a new twist-rub tester and found a relevant evaluation approach to evaluate the anti-loose performance of different asphalt mixture. By comparing the two test methods, ultimately determine the asphalt mixture loose comprehensive evaluation method.Based on the "twist" rub loss characterization of loose performance of different asphalt mixture, the influential factors of the asphalt mixture loose damage were studied. The increase of asphalt light component content can also lead to "twist" rub greater damage; different grades has different effect, open gradation asphalt mixture is prone to "twist" rub loose, dense gradation at high temperatures is also prone to "twist" rub loose destruction; Aggregate of lithology, construction and maintenance and so on will have a significant impact.Finally according to the characteristics of asphalt mixture of friable destruction the mixture ratio design method of asphalt pavement is studied. For its scope of application, design index, the design procedure, this paper gives some reasonable Suggestions.