Research On The Structure And Material Performance Of Asphalt Overlay On Old Cement Concrete Pavement

The asphalt overlay on old concrete pavement is one of the major rehabilitation ways. Because the old concrete pavement can't bear shearing stress and tensile stress at joint or crack. On which asphalt overlay is liable to damage and induce reflection crack by cyclic temperature stress and wheel loads. With the time going the reflective cracking keep on expanding for cyclic traffic and environment loads. So roughness and pavement performance are reduced.According to entitative engineering, Hening highway rehabilitation is studied in this paper. Through the study such as pavement condition survey and evaluation of carrying capacity, the primary causes of breakages are analyzed. Disposition measure is brought forward in allusion to different breakage conditions.Based on experience and harvest obtained home and abroad, pavement structure of asphalt overlay is studied out by forecasting future traffic capacity. Mid-layer of overlay structure is the most adverse layer in the whole structure by mechanics analysis, so the material composition design of mid-layer is considered as emphasis.According to the location characteristic of mid-layer, three sets of aggregates gradations named as adjusted AC-20I (Asphalt-Concrete-20I), AC-20I median and adjusted SAC-20 (Stone-Asphalt-Concrete-20), together with three types of general asphalt, SBS modified asphalt and TLA composition modified asphalt, are selected to constitute six sets of asphalt mixtures. By pavement performance's tests of these asphalt mixtures, water stability, stable in high temperature, cracking–resistance in low temperature, intensity and fatigue–resistance of mixtures are comparatively investigated. Then economic evaluation is carried out for six sets of asphalt mixtures. Thus optimal composition design of pavement's asphalt mixtures of mid-layer is put forward. Finally, influence extent of each ingredient for causing reflection crack is analyzed by test research. Furthermore, rationality of reflection crack evaluation method is proved in this paper.