The Influence of Aggregate Gradation on the Rutting Resistance Performance of Thin Asphalt Overlay
Thin asphalt overlay(TAO)is a commonly used technology for asphalt pavement rehabilitation,and its rutting resistance is closely related to the aggregate gradation.In order to investigate the effect of aggregate gradation differences on the rutting resistance of TAO mixture,AC-16 asphalt mixture is used.Three aggregate gradation with the same maximum nominal particle size are designed and indoor rutting tests are conducted on formed specimens.Five different 4.75 mm and 2.36 mm pass rate gradations are de-signed and Hamburg rutting tests are conducted on formed specimens.The results indicate that the aggre-gate gradation plays an important role in the rutting resistance of TAO,and the finer the aggregate grada-tion of the mixture,the more difficult it is to form the internal skeleton,resulting in a decrease in rutting resistance of the asphalt mixture.Therefore,optimizing the gradation of asphalt mixture by increasing the content of coarse aggregates within a certain range can significantly improve the rutting resistance of TAO.In addition,increasing the sieve pass rate of 4.75 mm and 2.36 mm in gradation will reduce the com-paction porosity of asphalt mixture,increase the depth of Hamburg rutting,and lead to a decrease in the rutting resistance;and when the void ratio is less than 4%,the depth of Hamburg rutting is more signifi-cantly affected by the void ratio;therefore,in practical engineering applications,the rutting resistance abili-ty of TAO can be greatly improved by reducing the aggregate content of 4.75 mm and 2.36 mm in grada-tion.
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