| Concrete Pavement is pavement structure type, cement concrete pavement in the mid-1960s, construction began in the 1990s has been developing rapidly, from the use of cement concrete conditions, the existence of many problems especially some of the early construction of varying degrees of a structural and functional damage, a serious impact on the level of service road and the safety. Cement Concrete Pavement Overlay study has been all road workers are a hot issue, but also a difficult one. Currently the overlay has not recognized the reasonable and feasible method and satisfactory overlay structure. Cement pavement overlay of the two structures:covered with asphalt overlay layer and cement concrete pavement, The study was to address asphalt overlay. The study of 104 National Road Line of Tai'an - Qufu renovation project for the prop, major study of the old cement pavement testing and evaluation, overlay structure design and impact-compaction technology, Paving of several different overlay structure of the test track testing has achieved good results. for the next step in the transformation of cement road from the structure of materials designed to provide scientific basis.Study of the main conclusions : (1)the original street scene of a large-scale experimental investigations, that the rapid growth of traffic volume and the increase of heavy traffic is causing the original cement concrete pavement damage factors. Through a variety of evaluation methods of comparing a reasonable evaluation method of cement pavement and objectives. (2)asphalt overlay fracture, the causes are as old cement concrete pavement cracks or joints caused overlay should to concentrate power, whether in vehicles or load temperature role, asphalt overlay of the greatest stress occurred at the seams. Therefore, the general ref- lection cracks have started from here and gradually expand upward until throughout asphalt overlay. (3)the asphalt cement concrete pavement overlay design method for the comparative analysis, Comparison of the United States Asphalt Association (AI), COE, AASHTO design methods and standardize our design method China proposed design of asphalt cement concrete pavement overlay design deficiencies exist, and using AI and the AASHTO method structure, the detailed analysis AASHTO design,According to analysis results of a test structure of the highway program; to overlay structure drainage design analysis, the drainage design. (4)the construction process control, the impact compaction (solid fracture) control points; Meanwhile cracks mitigation layer of the construction process and quality control requirements for the detailed study Crack mitigation layer to the application and lay the foundation for the promotion. (5) After more than three years of traffic load, road test so far found no one cracks Other sections of the same period there has been a lot of reflection cracks in the road test track is relatively small, The study shows the overlay structure can effectively prevent or reduce the incidence of reflection cracks, the same time to meet the requirements of high temperature stability.This paper is divided into six parts for research: Chapter I major domestic and foreign research Concrete Pavement overlay structure, Old cement concrete pavement overlay major study to reduce the number of cracks reflection and reflection slowed the pace of development of cracks, Foreign conducted a lot of research. China since the 1980s has conducted numerous studies, These studies concen- trated mainly in reflective crack control against the establishment and development of the mechanical analysis, and some anti-defense measures involve the entire pavement structure, which can be broadly divided into categories : Asphalt Overlay layer properties, Sandwich set intermediate layer or cracks mitigation, additional reinforcement layer and the old cement street broken stabilization. According to investigation results of this Concrete Pavement Reconstruction the overlay structure are four main forms, which contains the cracks mitigation layer structure (large-size mixture and grading gravel) thickening asphalt surface with conventional semi-rigid structure.Chapter II through traffic investigation and traffic survey and evaluation of the reasons for the road damage, discover that the roads are destroyed for many reasons. Actual traffic volume than the original design is estimated that the volume of traffic, the road has so far put into operation for 14 years. Axial load accumulated number reached 35.2 million axle, the original design life of the volume of traffic over six times. Pavement damage to the other main reason is the original concrete pavement design deficiencies. Thickness of a serious shortage, making it difficult to maintain an especially heavy traffic repeatedly role. Construction of the reasons for the road damage is also a factor.Detection from the scene, a concrete slab thickness of the individual locations fell short of the designed thickness, Basically, these positions have been destroyed, but there are some panel surface damage This is the concrete result of the quality. Construction in process control or strictly local grassroots strength low in the water and driving under the load generated by premature destruction. Cement Concrete Pavement perfect internal drainage system to enhance road subgrade drainage is a comprehensive road design, construction and maintenance of the key.Chapter III the road test developed structural analysis. Comprehensive investigation at home and abroad cement concrete pavement overlay structure design for the road test structure design, introduced by the United States AASHTO design method AI Design and COE design and integrate our design method According to the findings designed to determine the overlay structure design thickness.Chapter IV the impact compactor fracture solid principles, the impact to determine the frequency and quality control, identified quality indicators and parameters. Impact compactor pressure on the mechanical behavior of the surface is rubbed pressure, rolled and hit comprehensive role Concrete for the transformation of Old Road, will set up and in a stable, high efficiency, can significantly shorten the construction period. the project's implementation and follow-up testing stage. According to the overlay material characteristics of the pro- duction mix debugging, and the corresponding construction technology。Chapter V In the course of implementing the tracking quality control testing to ensure the quality of the road. After the opening of the road test on the use of state deflection changes of regular follow-up testing and analysis, Observation of the overlay structure performance changes.Chapter VI Conclusions and Outlook. The issue with State Road 104 Tai'an - Qufu of Cement Concrete Pavement Reconstruction Project System of the old asphalt cement concrete pavement overlay structure design and construction technology, and through performance testing and obser- vation to be the overlay structure of the program design. At home and cement concrete pavement overlay of family structure, Design and con- struction technology research has not yet mature, a complete set of technologies, Many research results also continue to improve and develop, there are still many problems which need further study. On the overlaystructure analysis are basically static parameters based on the static analysis, Dynamic analysis of the small, As for asphalt cement concrete pavement overlay structure of the dynamic analysis had been no precedent, Hence the need for asphalt overlay of dynamic load response analysis, Research asphalt overlay under dynamic conditions in the expansion cracks in the law; Road test the four overlay structure, Due to the shorter time the structure of the current four no cracks and other damage and the need for long-term performance of observation, Four to validate the effectiveness of the use of the structure for the future asphalt cement concrete pavement overlay provide optimal design. |
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