Study On Dynamics Process Of Interaction Between Oscillatory Drum And Hot Asphalt Mixtures

Compaction machinery is equipment that has a very close relationship with the properties of objects to be compacted, compaction methods and compacting techniques. As a new compactor, oscillatory roller makes rearrangement of material particles in a dense way with a mechanism of rapidly alternating shear stresses. The studies on the properties of oscillatory compactor, compaction theory, compaction techniques and the properties of materials are necessary. Through establishing the interactive dynamics model of oscillatory drum and hot asphalt mixtures, the paper makes a sample machine of oscillatory roller and some tests on the spot for studying the dynamic identification of parameters of dynamics model, discusses the differences between the oscillatory compaction techniques and the vibratory compaction techniques, and analyses the amplitude-frequency characteristics of oscillatory drum. On the basis of tests on the spot, the paper optimizes the parameters of dynamics model about oscillatory drum, using the results of the parameters optimization, establishes the energy balance equation of oscillatory drum in the compaction process, and puts forward the calculation model and the equation of oscillatory compaction under two conditions of the simple rotation and the slip-rotation.On the bases of theory analysis, tests on the spot and data analysis, the paper gains the following conclusions:1. As for the two compaction techniques of the oscillatory compaction and the vibratory compaction, the former is more effective than the later in the course of the compaction of thin-layer asphalt concrete;2. The degrees of compaction keep linear relationship with the number of times of compaction under the logarithmic coordinates. Within a certain range of oscillatory compaction speed, the increase rate of the compaction degree remains stable to make it possible to further optimize compacting techniques. Under the conditions of different times of compaction to choose the different compaction speed, the required degree of compaction can be gained within the shortest time. These results can be used to guide the construction.3.The results show that the effects of the vibratory compaction on the bridge are more serious than the oscillatory compaction; The influences of oscillation basefrequency on the bridge of are smaller than its double frequency; The influences of the vibration base frequency are higher than its double frequency.4. In the study of interaction between the oscillatory drum and the hot asphalt concrete, the parameters of compacted material are identified , such as the stiffness and the damp etc. With the increase of the degree of compaction, the stiffness of compacted material increases, but the damp decreases.5. According to the simulation result of dynamics model with computer:(1) With increase of the stiffness of compacted material, the amplitude of the second resonance point increases, but the amplitude of the first resonance point decreases; and especially the amplitude of sliding plate (compacted material) increases greatly.(2) With increase of the damp of compacted material, the amplitudes of resonance point decrease, especially the amplitude of the second resonance point.6% In the optimization process of oscillatory compaction, the paper establishes the calculation model and the equations of effective compaction power in different stages, suggests the target functions and the indexes for optimization process of oscillatory compaction.(1) If there is no slip-rotation between the oscillatory drum and the compacted material, the effective compaction power is direct ratio to the square of displacement amplitude. Once the combination of the amplitude and the frequency is optimum, the effective compaction power is the biggest.(2) If there is slip-rotation between the oscillatory drum and the compacted material, there is an optimal combination of the slip-rotation ratio, the amplitude and the frequency to make the effective compaction power absorbed by compacted material within unit time is the biggest.The above researches on the dynamics process of oscillatory drum and hot asphalt mixtures provide theoretical basis in improving the compaction machinery performance, the compaction efficiency and realizing the intelligence of compaction machinery.