Research On Asphalt Overlay Technology Of Existing Cement Concrete Pavement

The construction of cement concrete pavements in our country begins at the middle of 1960's. At present, a majority of cement concrete pavements constructed in early periods have been close to or exceeded its design age-limit, mostly appearing damage to some extent. It is necessary to maintain or reconstruct the existing cement concrete pavements. The reconstruction of existing cement concrete pavement with an asphalt overlay has the advantages of short work period, little influence on traffic, little investment and comfortable drive etc, which is a kind of reliable and effective rehabilitation measure at home and abroad.Stone Mastic Asphalt (SMA) is the mixture of asphalt pavement with stronger deformation resistance ability and better durability, and it is generally accepted by current international. The Tangxia section of S358 rehabilitation engineering of existing cement concrete pavement is studied in Dongguan City of Guangdong Province in this paper. The detailed presentation of distress survey and evaluation methods of cement concrete pavements for treating to provide a basis to the existing pavements. The paper studies the match ratio design and related materials of SMA, in the meantime studies construction techniques and construction quality control methods of existing pavement rehabilitation combined the process of pavement construction. The present paper analysis the theory producing reflection cracks of asphalt overlay on the existing cement concrete pavement, the prevention and control measures, also studies the principle respectively how the geotextile prevents and controls reflection cracking, and introduces their construction techniques in detail.The paper point out that the comprehensive investigation and correct processing of cement concrete pavements are the important step of the overlay engineering. The indexes of subgrade moduli and relative deflection differences are put forward to evaluate the structure performance indexes of existing pavements. The geotextile has good effect at the aspect of preventing reflection crack and rutting. Looked from the SMA application effect, the surface layer uses 4cm thick SMA to be well displays SMA the water stability and fatigued resistance performance. The particularity of SMA material performance had decided its particularity of production and construction, and it should strictly control each link in the actual operation process. The successful keys of the overlay engineering lies in the careful design and the careful construction.The paper indicates that ovlerlaying SMA asphalt modification mixture oh existing cement concrete pavements not only is feasible in techniques, but also improves the riding quality and the traffic condition, lengthens the service life, saves funds, and shortens construction time of existing pavement rehabilitation. The SMA overlay is suitable to Guangdong Province of this kind of high temperature, the multi-rain and very heavy traffic area especially, which has better economic benefits and social benefits. The popularization of the techniques has a broad prospect in existing pavement rehabilitation project.