Research On The Evaluation Of Asphalt Pavement Performance And The Decision Of Overlay And Rehabilitation Based On The Status Of Cement Stabilized Base Layer

At present,the existing evaluation index system of asphalt pavement performance in China is set up completely according to apparent technology status of pavement,while it has a decisive significance for pavement maintenance decision-making to ascertain the status of asphalt pavement base layer.Therefore,the new research,the status of pavement base layer stabilized by inorganic binder,was presented in this paper.The Road Base Condition Index which is based on the pavement distressed characteristic of highway in Liaoning province and pavement inspection data that has been collected for many years is put forward in this paper,the definition of these index and relevant calculation method has been presented as well,which will provide a new idea for asphalt pavement maintenance decision-making.Firstly,vast detection and investigation were made on technology status of highway in Liaoning province.Pavement distress,roughness,detection techniques on pavement rutting,detection techniques on pavement anti-sliding performance,detection techniques on pavement structure strength,and the detection techniques on integrity of the pavement structure were recommended in this paper in terms of the detection principles,the detection equipment and the detected content and so on.Secondly,the primary distress modes of semi-rigid base asphalt pavement could be concluded by utilizing the detection and the results of the detection.Each distress and its distressed mode were analyzed according to two aspects,the occurrence mechanism and the appearance features of each distress,from which structural damage and none-structural damage could be distinguished,in order to make preparations for putting forward new evaluation index of base layer,and to establish a basis for subsequent theoretical analysis.Thirdly,evaluation index of pavement base layer,RBDR and RBCI,were presented and detailed calculation method was provided.As for network-level,base layer status is diagnosed by utilizing the method of image artificial recognition,in order to make statistics of base layer distress probability for each types of distress,which guaranteed the reliability of 80%,thus the mapping relation model between surface distress and base layer distress was established.As for item-level,numerous core samples aiming at various types of distress have been drilled.Based on the principle of fuzzy-neural network,the cracked results of drilled core samples were predicted via parameters such as distress characteristic,natural conditions,pavement structure,and traffic volume.That has a prediction accuracy of 84%,so the diagnostic model for fuzzy-neural network was established.Mean value,variance,kurtosis and skewness from statistics were introduced to reflect the distribution characteristics of base layer distress status,by which 5 types of base layer distress distribution characteristics was distinguished:type of overall integrity and local damaged,type of scattered damaged,type of overall damaged and local integrity,and type of overall damaged and local integrity.Fourthly,panel data transition probability Markov Model was utilized to predict the deterioration process of pavement.Five grades for pavement status and relevant boundary value was ascertained according to asphalt pavement performance evaluation index(PCI,RQI)and evaluation criteria.Decay equation parameter of pavement performance-?,?,?-was figured out via panel data method,so the deteriorative Markov transition probability matrixes were obtained by calculations under the pavement status of different pavement structure and different traffic volume.Then the prediction for pavement decay law was realized.Fifth,fuzzy comprehensive evaluation method was utilized to evaluate on pavement technical status.Massive data samples were calculated by this method meanwhile.With national highway G202,G305 pavement detection data being taken as examples,the influence weight on pavement performances of every evaluation detection index was figured out and the technology status of the sample road was evaluated quantitatively.The calculation result is consistent with the actual situation and artificial judgment which showed the evaluation method is feasible.Sixth,based on the existing analysis of asphalt pavement maintenance decision-making system,combined with the textual research results on base layer technology status,the network-level decision-making system and item decision-making system were established,which will provides theoretical basis for highway asphalt pavement maintenance decision-making.Seventh,according to the maintenance decision-making result that has been determined previously,under the hierarchy of item-level,the pavement maintenance program of Ku-er Road(section of Yulou-Tianzhuangtai)was taken as an example to be designed.