Study On Structural Performance Evaluation Methods Of Old Cement Concrete Pavement Of Freeway

Structural performance evaluation of old concrete pavement is precondition and basement of overlaying and rebuilding . The project of overlaying and rebuilding on the old pavement is supposed to make full use of the structure of the remained pavement. The scheme can both make the structure be able to bearing the weight of traffic loads in future, and save the cost of project.A structure performance evaluation system of old concrete pavement was erected based on tradition testing method of old concrete pavement, relying on the research item"performance evaluation of old pavement and countermeasure to widening of the communal section of the third ring road of Wuhan city and the Wuhuang freeway". The structural performance evaluation of old concrete pavement could be divided into two parts: the first one was the structure integrality evaluation of old concrete pavement; the second was the assessing of structure parameters of old concrete pavement. The structure integrality included three parts: the structural damage condition, the load transferring performance of block seam, the condition of interspacing beneath slab.First, ADINA software and orthogonal experimentation method were used to carry through the three-dimensional finite element emulation analysis of deformation and stress of slab under the standard load. Based on the results of deformation emulation analysis, new evaluation method and evaluation criterion could be erected and the degree of impact of the load transferring performance of block seam and the condition of interspacing beneath slab to the structure integrality could be determined . Accordingly the weight coefficient in the synthetic evaluation of structure integrality can be determined.Second, the structural damage condition, the load transferring performance of block seam, the condition of interspacing beneath slab was evaluated. According to the method in the criterion, the structural damage condition was depicted by DBL index ; the load transferring performance of block seam was depicted by the average deformation transferring index of the section of road; the condition of interspacing beneath slab is depicted by the interspacing ratio of the section of road. Third, the structure integrality was synthetically evaluated. The prevalent methods were used to evaluate the structure integrality of the communal section of the third ring road of Wuhan city and the Wuhuang freeway. By further researching on the results and the evaluation methods ,the gists and rules were reached for selecting the right and reasonable model to evaluate.Last, the structural parameters were assessed, the values and variability level of the structural parameters of the communal section of the third ring road of Wuhan city and the Wuhuang freeway were gained. The firsthand data was provided for the calculating in the design of overlaying and rebuilding.