Old Cement Concrete Pavement Asphalt Overlay Transformation Studies

Based on understanding of many practices of asphalt overlay on old cement concrete pavement in our country and rehabilitation of Boai road in Zhongshan city, this paper analyzes and studies the rehabilitation technology of old cement concrete pavement systematically, includes:(1) The assessment for structure characteristic of old cement concrete pavementA correct assessment for pavement distress and structure characteristic of old cement concrete pavement before overlay is the stick point of preventing reflection cracking and guarantee the success of rehabilitation, which requires understanding how the structure characteristic of old pavement effects the stress and reflection cracking of the asphalt overlay. This paper analyzes how structure characteristic of old concrete pavement affects the load stress of asphalt overlay by the three dimensions finite element analysis program-ADINA.(2) The asphalt overlay design in rehabilitation of old cement concrete pavementAsphalt overlay design not only relates the distress, structure characteristic, traffic and environment of the old pavement, but also requires reasonable mechanics model, correct material parameter, effective measure of preventing reflection cracking, and so on. So there is still not a matured design method up to now. This paper introduces several relatively matured design methods and puts forward some problems which require more study. This purpose is to accelerate the study of asphalt overlay design in our country.(3) The prevention and control of reflection crackingBy detailed analysis of generation mechanism of reflection cracking, this paper also studies the principle respectively how the geotextile and glass fiber grid prevents and controls reflection cracking, and introduces their construction crafts in detail. Their advantages and shortcomings are also analyzed comparatively in this paper.