Recently, the study of machinery/medium interaction is becoming increasingly important in terramechanics. In order to maximise the performance of existing equipment and obtaining desired compaction density in road construction, reasonable and effective paving operations are essential. However, the operations always depend on empirical approaches. In this paper, a model based on vibration compaction theory was used to describe the deformation property of asphalt mixture, which can lay a foundation for future analysis. And then, a dynamic model of tamper/asphalt mat interaction, based on the principles of resonance, was developed to predict asphalt mat density during paving operation. The model inputs included excitation frequency, tamper stroke, paver forward speed and asphalt mixture properties parameters for different tamper or asphalt mixture. The numerical simulations are provided to demonstrate how the tamper/asphalt mat interaction model can be used to predict asphalt mixture compaction in the field of road construction engineering.

Compaction uniformity is essential to the successful performance of asphalt pavement. Therefore, understanding the characteristic and full evaluation on the overall density distribution in field construction is necessary. An available method capable to assess compaction uniformity of the hot paving layer was proposed by considering both longitudinal and transverse density distribution. Field tests of density distribution behind pavers and rollers were conducted on two test sections, respectively. Then, the quantitative evaluation indexes of uniformity (i.e. the range (R), coefficient of variation (CV), repeatability standard deviation in detection track (Sr), etc.) were used to analyse compaction uniformity and the severity of non-uniformity of the asphalt mat. Moreover, the uniformity variation from paving to rolling was evaluated through the tests and a compaction uniformity model. Results indicated that rolling compaction could intensify the degree of non-uniformity of the paving mat, although all the density after rollers is higher than the density behind pavers, and simulation analysis corresponds with the test results. The uniformity of density distribution in transverse is worse than in longitudinal. Tamper seemed to be more effective than other parameters at improving the initial density, while frequency of vibrator appeared to have the most impact on transverse compaction uniformity.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

In order to make thin layer paving one-step shaping during polymer concrete pavement construction, the relationship model between vibration parameters, structure parameters and the degree of compaction is established in this paper. Based on the resonance theory, this model is integrated with a mathematical model to study the dynamic properties and the interaction mechanism between vibration mechanism and paving material during compaction. The model represents the structure parameters, vibration parameters, driving speed, degree of compaction and the interaction between them. Combining real engineering with adequate quality control technology, the pavement is finished by only one step paving. The results show that, when the vibrating frequency is greater than the optimal vibration frequency and driving speed the driving speed is less than the speed threshold as well as between 2.5~3m/min, the initial compaction degree of the paving is more than 96%. Thereby improving construction efficiency and guaranteeing the construction quality. Thus, the optimal range about vibrating frequency and speed can serve as a valuable reference for one-step shaping of thin layer paving and the dynamic model can also be used to study the compaction process of pavements during the construction.

In order to evaluate the structural strength of loader working device in a comprehensive and accurate way and obtain the position of load spectrum measuring points of the working device of loader, the finite element model of the working device of ZL50G loader was established with hexahedral elements mesh. The finite element model was built on the stress analysis of the force model of bucket of the working device. The finite element strength analysis was carried out on the working device structure of the loader, and the stress value of the structure under different working conditions was obtained. The locations of the dangerous points of the working device of the loader were effectively determined. The finite element calculation results showed that: the partial load condition in shovel digging operation was the most dangerous working condition, and the moving arm was the largest load-bearing component. The field test was carried out on the working device of loader. The test results showed that the finite element calculation results were in agreement with the test results. The influence factors of the strength analysis of the working device under the load condition were defined. It also made it clear that the action of the lateral force must be taken into account when testing the load spectrum of the working device. The analysis results provide the reference resources for the load spectrum test and fatigue life analysis and structure optimization of the working device.