Research On Material Of Stress Absorbing Layer Asphalt Mixture And Experiments Of Pavement Performance

Reflective cracking is one of the common diseases for the existing cement pavement to overlay asphalt layer or semi-rigid base asphalt pavement. It is an effective measure to prevent reflective cracking to set stress absorbing layer between the existing cement pavement and asphalt overlay or between the semi-rigid base and asphalt pavement. The performance of the stress absorbing layer has a great influence on the effect of preventing reflective cracking.The main research of the article is the proportion design and the pavement performance of stress absorbing layer modified asphalt mixture. There are four kinds of asphalt(SBS modified asphalt, Superflex modified asphalt, TPS high viscosity modified asphalt and Rubber asphalt) to make a comparative analysis. The main research contents include the following aspects.Experiment with four kinds of asphalt(SBS modified asphalt, Superflex modified asphalt, TPS high viscosity modified asphalt and Rubber asphalt) to ensure their technical performance. The results show that the dosage of Superflex enriched asphalt in Superflex modified asphalt is 18% and the dosage of rubber powder in Rubber asphalt is 15%.Use Superpave volume design method to make stress absorbing layer proportion design,and the controlling index of the target gradation lies on the voidage. The design method help to make test samples and determine some performance experiments to indentify the optimum bitumen-aggregate of the four types of asphalt mixture. Superpave mathematical formula method is applied to estimate the bitumen-aggregate of the modified asphalt mixture to validate the actual asphalt content of the modified asphalt mixture.The experiments research on pavement performance are carried out for the five types of stress absorbing layer modified asphalt mixture including high temperature performance, low temperature cracking resistance, stability in water, fatigue resistance and the performance of the whole structure which is constituted by modified asphalt stress absorbing layer and asphalt pavement. The results show that stress absorbing layer modified asphalt mixture has good pavement performance and delays the generation and extensions of reflective crackingeffectively.