Research On Construction Process Control Of Asphalt Layer Based On BIM Technology

For the high-class highways in our country,the proportion of asphalt pavements is relatively high,which is mainly due to its advantages of good evenness,no joints,short construction period,comfortable driving,and low noise.However,with the widespread adoption of asphalt pavement structures,the early distresses in asphalt pavement have gradually attracted the attention of road researchers.Early distresses not only significantly reduce the service quality and service life of the road,but also pose a serious threat to the driving of the vehicle.Through investigation and discovery,it was found that there are many reasons for the early distresses in asphalt pavement,including design,construction and maintenance.Among them,the construction quality issue of asphalt layer is one of the more important reasons.The construction process control of asphalt layer directly affects the road service period and quality.Therefore,the research on the construction process control of asphalt pavement has become a hot topic at home and abroad.The BIM(Building Information Modeling)model has been applied in the field of construction control of building,and some progress has been made.In order to ensure the quality of asphalt layer construction,it is necessary to carry out the research on construction process control of asphalt pavement based on BIM technology.The main research contents are as follows:(1)Control indices of construction process based on the performance of asphalt layer.Based on the laboratory tests,the influences of the variation of the construction control indices on the high temperature-performance,low temperature-performance,fatigue-performance,and water stability-performance of asphalt mixture were analyzed.For analyzing the effects of gradation segregation and temperature segregation on the performance of asphalt mixture,the influence of the non-segregation area on the segregation area of asphalt pavement was considered in this research.Based on a test road,the PQI(Pavement Quality Indicator)was used to measure the density of the asphalt mixture to analyze the influence of the variation of the number of roller passes on the performance of the asphalt mixture.According to the test results,the influence degree of gradation,asphalt-aggregate ratio,gradation separation and temperature segregation on the performance of asphalt mixture was clarified,and the key control indices were given in this study.(2)Real-time monitoring of construction control indices of asphalt layer based on BIM technology.The sieve test based on machine vision(STMV)was used for predicting the real-time gradation of asphalt mixture in the mixing process.In the laboratory,the STMV was used to analyze the influences of flow rates and layer thicknesses for aggregates on the prediction accuracy of aggregate gradation.The test results showed that,under the same flow rate,the prediction accuracy of aggregate gradation decreased with the increase of the layer thickness for aggregates.Under the same layer thickness,the prediction accuracy of aggregate gradation decreased as the flow rate of aggregates increased as a whole.According to the results of STMV,the flow rates and layer thicknesses have less effect on the prediction accuracy of the gradation of asphalt mixture compared to various specifications of aggregates.The appropriate thickness combination for various specifications of aggregates is conducive to obtaining a more accurate gradation of asphalt mixture by the STMV.The verification results of the road projects showed that the prediction accuracy of the STMV is better than that of the online detection of the asphalt mixture plant based on the results of the extraction test.In this research,the RFID(Radio Frequency Identification)technology was used to determine the location of a transportation vehicle of the asphalt mixture,and then the construction information was mapped to the pavement location.The infrared temperature sensor was used for the real-time detection of initial rolling temperature.After the construction information is processed in the background,the construction information can be timely released to the InfraWorks platform to facilitate the participants to view and monitor the construction process.(3)Prediction of the asphalt pavement performance based on real-time monitoring data.Conventional control method for the construction indices of asphalt layer is not conducive to reducing the risk of early distresses in asphalt pavement.JTG D50-2017 disease prediction models were selected for the real-time estimation of asphalt pavement performance in this study.In order to establish the connection between the detection values of construction indices and JTG D50-2017 disease prediction models,the model for the permanent deformation of the rutting test was established using gradation,air voids,and effective asphalt content based on AC-13 and SUP-20 two types of asphalt mixture.This deformation prediction model has a high regression coefficient.The Bailey parameters,asphalt-aggregate ratio and mold temperature were used to establish the air voids prediction model of asphalt mixture.The regression coefficient was also high.The Witczak model was selected for predict the dynamic modulus of the asphalt mixture,which can be used to calculate the structural mechanics response of pavements.This model was calibrated based on the results of dynamic modulus test of AC-13 and SUP-20.Based on a test road,the real-time prediction methods of permanent deformation and fatigue life of asphalt mixture layer were illustrated in this study.(4)Construction information management based on BIM technology.The real-time estimated values of the asphalt pavement performance can be timely released to the InfraWorks platform,and the construction information can be mapped to the location of asphalt layer to facilitate construction quality control.The results of goodness of fit test showed that the prediction results of permanent deformation and fatigue life of the asphalt mixture layer in the mixing stage obey the normal distribution.The control charts for the individuals-moving range were used for the asphalt pavement performance to detect whether or not the real-time estimated values were abnormal.The construction quality was assessed using the deviation between the average real-time estimation values of the asphalt pavement performance and design values,and the variation coefficient by dynamically summarizing a certain number of prediction data of asphalt pavement performance.In addition,the types of construction information that InfraWorks platform needs to collect were given.After the construction information is summarized,the InfraWorks platform can be used to map the construction information in different time and space conditions with pavement location information to realize the traceability function of the construction information.Moreover,when the construction is completed,the BIM model containing the construction information can be safely and reliably stored and handed over to different management departments for supporting the subsequent phases of the asphalt pavement life cycle.