The Key Technology For Renewal And Repaving Of Existing Cement Concrete Pavements Under Heavy Traffic

The cement concrete pavement in our country has developed for more than70years. At present, quite a number of the existing cement concrete pavement has gonebeyond or close to the service life period, due to the large increase of traffic volumeand heavy vehicle number, the original design of cement concrete pavement could notmeet the requirements of the current transportation, and after years of use, they hasemerged a large number of diseases, must carry out technical transformation, Someroad did not meet the design life, but due to overload use or construction, etc, alsohave appeared severe damage, and affected the road use performance. Reconstructionof old road must solve and deal with the following key issues, namely can old road bemake full use of? How to use? How to design reasonably and construct?, etc.Combined with practical engineering, this paper made systematic and deep researchesaround the above key problems, the main results were as follows:(1)The disease of the old cement concrete pavement is investigated and thecauses of diseases is analyzed, and the type of disease and the extent of disease isclassified, can be seen from the investigation, crushing plate, cracks, voids fractureand explicit are the main disease types of this project.(2)The index of pavement evaluation is introduced from using performance andstructure performance, and the road surface is evaluated, it is concluded that theconcrete pavement distress condition, the condition of road roughness, empty beneathpavement slab of the original cement concrete pavement is evaluated as bad level,skidding resistance and joint load transfer capacity of the pavement is evaluated aspoor level; Based on the index of the evaluation, this paper puts forward a kind ofcomprehensive performance evaluation of old cement concrete pavement modelbased on fuzzy matter-element.(3)S function model, GM (1,1) model and the improved GM (1,1) model forthe prediction of the pavement performance is put forward,, and forecasting precisionof the three models are analyzed, it is concluded that prediction effect of the improved GM (1,1) model is the best of all, the GM (1,1) model comes second, Sfunction model is poor for medium and long-term prediction, GM (1,1) model andthe improved GM (1,1) model is proposed for predicting, but the original data needsupdating timely in the prediction and suggest that time limits of prediction shouldnot exceed more than five forecasting period.(4) Based on the improved scale of analytic hierarchy process and fuzzycomprehensive evaluation method and on set pair theory, the model for pavementcomprehensive treatment method is established, according to extent of damage of theroad, the scheme of pavement treatment is decided from the engineering cost,construction speed, utilization of old panel material, solving the reflection crack, theservice life of the target, the influence on the surrounding environment and ancillaryfacilities along these seven aspects, ultimately, determining that rubblization ismost suitable for this project.(5)Based on the the preliminary design of overlay structure, according tosimulateing and analysing the tensile stress in the bottom of layers under differentthickness of overlay structure by ansys, getting the optimized paving layer structure.(6) The construction technology and requirements of rubblization, cementstabilized macadam and asphalt overlay is introduced in detail, some quality controlcriterion of rubblization is proposed.