High-compactness paving characteristics of asphalt pavement under combined load

To improve the initial compactness of the asphalt pavement and obtain the high-compactness characteristics of the paving mixture after the screed of paver operation, the effect of the combined load generated by the tamper and vibrator was considered. In view of the screed's dynamics characteristics and its compaction effect on the paving mixture, the dynamics model of the screed compaction system was established. Based on the displacement changes in the screed under different frequencies of tamper and vibrator, the relationship between the compactness of the paving mixture and the dynamic response of the screed was analyzed. The simulation design was carried out by the orthogonal test method. Taking the average displacement peak of the dynamic response of screed as the evaluation index of compactness, the compaction effect of the mixture under the combined load generated by the tamper and vibrator was analyzed. A test was carried out to observe the high-compactness paving effect of the screed on the mixture. The compactness of the pavement under the action of only the tamper and the variations in the paving compactness increment with the tamper frequency after the addition of the vibrator was verified, and the correlation between the compactness increment and the paving compactness under only the tamper load was analyzed. Research results show that when the difference between the vibrator frequency and the tamper frequency increases, the impact of the tamper load on the displacement peak of the screed is not significant. The vibration compaction can compensate for the compactness of the weak compaction position of the tamper, but there is a compaction limit. When the tamper frequency is 10-18 Hz, and the corresponding vibrator frequency is 30-40 Hz, the combined compaction of tamper and vibrator achieves the best state, which can improve the compactness of the mixture and avoid the overcompaction of the mixture by the screed during the high-compactness paving operation. When the vibrator frequency is within or exceeds the high-compactness frequency range, the compactness increment of the mixture varies by 2%-6%. 6 tabs, 13 figs, 31 refs. © 2023 Chang'an University. All rights reserved.