Study On Performance Of Warm Recycled Asphalt Mixture With High RAP Content

As a result of the environmental and traffic loads,the asphalt pavement gradually entered the stage of damage and destruction.Early and appropriate preventive maintenance is essential to repair road damage in a timely manner,delay damage,and improve road use efficiency.Regeneration technology is one of the related technologies that has received a lot of attention in recent years.Asphalt pavement regeneration technology is the reprocessing of waste asphalt mixture(RAP)to restore the original road performance,so as to achieve the effect of reuse.However,the mixing ratio of RAP materials in conventional thermal regeneration technology is low,and a large amount of exhaust gas is generated during the construction process,which leads to adverse factors such as environmental damage.Combining warm mixing technology and regeneration technology can not only effectively improve the related road performance of waste pavement,but also reduce the secondary pollution during the construction process,so as to achieve the purpose of real energy saving and environmental protection.In this paper,100% RAP warm-mixed recycling technology is applied to the waste asphalt mixture in the target maintenance section,and relevant performance tests and experimental studies are conducted on 100% RAP warm-mixed recycled asphalt and its mixture.The research results have certain guiding significance for the implementation of such road maintenance technology.The research carried out the following work:(1)Study on the aging and regeneration mechanism of asphalt and warm mixing technology mechanism;determine the gradation of waste asphalt mixture,and evaluate the performance index of old asphalt.(2)Study on the effect of different dosages of regenerant on the performance of different indexes of asphalt during the warm mixing process,so as to summarize the trend of performance changes.At the same time,the optimal dosage of regenerant is determined through the changes of various indicators.Reagent dosage selection: 2%-8%,the relevant tests to determine the optimal dosage are: three major index tests,rotational viscosity test,DSR test and BBR test.The results show that the performance of the warm-mixed recycled asphalt with the 4% regenerant dosage is the best.(3)Study on the effect of mixing temperature and warming agent on the road performance of warm-mixed recycled asphalt mixture,so as to determine the best optimal mixing temperature.In this study,the viscosity temperature curve method and volume parameter method were used to determine the optimal mixing temperature.Explore the high temperature performance,water stability,mechanical properties and low temperature performance of 100% RAP warm mix recycled asphalt mixture.The results show that: under the optimal mixing temperature,all road indexes of 100% RAP warm-mixed recycled asphalt mixture meet the requirements.(4)Study on the durability of 100% RAP warm mix recycled asphalt mixture.The durability of the mixture was evaluated using the cyclic freeze-thaw split test and the cyclic freeze-thaw trabecular bending test.The results show that when the number of cycles of freezing and thawing increases to a certain degree,the water damage resistance and low temperature crack resistance of the warm-mixed recycled asphalt binder gradually deteriorate.