Asphalt Concrete Overlay On Rehabilitation Of Old Portland Cement Concrete Pavement

This paper base on Liu-Nan freeway rehabilitation of Guangxi, aim to the difficulty of asphalt concrete(AC) overlay on ailing Portland cement concrete(PCC) pavement, through the systemic study such as pavement condition survey, approaches design, theoretic analysis, testing, construction practice, form a complete technology of AC overlay on rehabilitation of old PCC pavement.Liu-nan freeway is experienced heavy traffic volumes, the slab deteriorate badly. In order to guarantee the path travel firmly the security and comfortableness, it must be rehabilitated. In order to explore the complete technology of AC overlay on rehabilitation of old PCC pavement, the design of asphalt concrete overlay has assimilated the successful case experience of both domestic and abroad, and has considered specific factors, such as local climate, traffic and current pavement conditions, etc. , and has carried on the multi-project design. Through experiments the road section project practice examination, ensured the key technological question about the overlay structure, mixture ratio, construction techniques. Reflect crack is another overlay nodes. In order to alleviate reflection crack that might arouse in future, several kinds guard against the crack measure was applied to existing concrete pavement, such as layer of waterproof and alleviate reflection crack, stress absorb layer of geotextile and improved asphalt.The construction techniques of asphalt concrete are mainly introduced from the following aspects: construction mixture ratio design, construction of asphalt overlay, construction of STRATA stress absorb layer, etc.. In construction of asphalt overlay, the high temperature and rainy climate of Guangxi Province has been taken into account especially so as to reduce water damage and increase high temperature stability, and to guarantee construction quality, raw materials, roughness, initial impact intensity, road surface impact intensity, etc. been checked with high demands and criterions.Through with careful design, strict construction, Liu-Nan freeway rehabilitation achieved successful result and totally reach the expected extent. After completion approval, the methods adopted in the original design proved effective. The project design proposal and the construction techniques applied research provide some reference for the design and decision-making of maintenance and reconstruction of the cement concrete pavement in the future.