Research On Used Asphalt Pavement Evaluation And Rehabilitation Method

Qinghai-Tibet Plateau's special geographical position brings up a distinctive geographical style and features,also make highway construction and maintenance a serious problem. Since the completion of the Qinghai-Tibet highway, several rehabilitations were processed. During the building of the Qinghai-Tibet railway, Qinghai-Tibet highway endured a large traffic volume. The pavement condition investigation found that many kinds of diseases such as cracking, sinking, surface abrasion were found. Based on the special condition of Qinghai-Tibet highway, making a proper evaluation for pavement condition and taking proper measures were important to maintain the serviceability of highway and retrench investment.In pavement condition evaluation, there was not a criterion to choose indexes before. Paper used the entropy to weigh the variation of indexes, and employed it to select the indexes for pavement condition evaluation. AHP (Analytical Hierarchy Process) model was constructed for comprehensive evaluation. In the model grey-theory was used to evaluate the single index.Intensity evaluation conducted by getting a equivalent modulus of elasticity, overlooked that pavement was a multi-levels structure. So modulus back-calculation was a more powerful tool to identical the structure condition. ACO (Ant Colony Optimize) was a typical simulated arithmetic, with a good calculation capacity. Corresponding the ants'paths to the modulus of pavement, the back-calculation processes can be attained. Results shown that compared with other method base and subbase modulus was very close, but a little discrepancy for surface layer.Based on the aim to maintain the primary pavement rehabilitation system, paper used the mechanics-empirical method to design the overlay heighth. Employed the three-coefficient formula, the actual form of F was got. Used F in Qinghai-Tibet highway rehabilitation project found that the overlay heighths accord with expectation very well.