The Comprehensive Treatment Of Existing Cement Concrete Pavement And The Design Of Asphalt Concrete Overlay On It

The traffic volume increased sharply, especially the increase of overloaded vehicles, have resulted in serious damage to cement concrete pavement in Xuanguang freeway, which seriously affected the comfort of travelling. As a result, it is in dire need of renovating.This paper is relay on the renovation and pavement reconstruction on old cement concrete pavement of Xuanguang freeway. Through detailed on-site investigation, in-site testing, field test and laboratory test to obtain and master the damaged condition of cement concrete panel ,the intensity of pavement and subgrade. After assessing the structure of the pavement and analyzing the reasons for the destruction of road in detail, author decided to take corresponding countermeasures for most sections, that is, impact-compaction and rubblization technology .The rest,which are not suitable for that two methods , are dealt with other measures according to the disease.Putting up asphalt concrete overlay on old cement concrete pavement is the core of the design of the whole project. The asphalt concrete overlay structure is determined by multilayered elastic system combined with the experience of similar projects. The United States four methods are used for checking. At the same time, the laying of geotextile and other technical measures for preventing reflection cracking are taken for those sections that are not punched.Through the study of the overlay material and the study of the asphalt design on the overlay, author have attained general conclusions: the old cement concrete treatment and water facilities improvement are important link in the whole renovation and pavement reconstruction; impact-compaction and rubblization technology are apt to deal with the old concrete slab and prevent the reflection cracking; the increase of asphalt content can effectively improve the asphalt shear strength; asphalt concrete in the best conditions of mixing ratio can be a very good standard to meet the technical requirement; adding the polyester fiber BST into the asphalt concrete can increase the stability of the road bed and road surface; cracking resistance indicator for different materials and structures is a lot of different; it does not need to consider the original concrete slab modulus too much in the pavement design, increase the basic modulus is effective in the prevention of the reflection cracking before putting up the asphalt overlay.Asphalt reconstruction project quality control is the key to the renovation and pavement reconstruction, the asphalt mixing, transportation, paving and compaction have to meet regulatory requirements, and construction errors should be in the provisions.