Study On The Performance Of Warm Mix Recycled Modified Asphalt And Its Mixture

The warm mix recycling technology of asphalt pavement is a combination of warm mix technology and recycling technology,which not only realizes the recycling of resources,but also achieves the purpose of energy saving and emission reduction,with good environmental and economic benefits.In the current research,the research on warm mix recycling technology of modified asphalt is relatively less and mainly focused on the performance of the mixture,lacking the understanding of the performance change rule of recycled modified asphalt under the joint action of aging asphalt and warm mix recycling additives.Referring to the evaluation method of cement performance based on road performance in SHRP,the author evaluates the performance of warm mix recycled modified asphalt with different aging asphalt content,and analyzes the applicable content of warm mix recycled asphalt,and then compares and verifies the road performance of warm mix recycled asphalt mixture.The main research methods and conclusions are as follows:The three indexes of asphalt and the results of infrared spectrum test show that WL can recover the micro structure and macro performance of SBS modified asphalt matrix,but it has no recovery effect on the aging degradation of the SBS modifier.The results of temperature scanning and multi stress repeated creep tests show that the unrecoverable flexibility₉)can reflect the high temperature performance of the recycled modified asphalt comprehensively.With the increase of the aging asphalt content,the high temperature performance of the recycled modified asphalt first increases and then decreases,and the addition of the warm mix recycling agent has a negative impact on the high temperature performance.The results of temperature scanning and time scanning test show that the increase of aging asphalt content increases the dissipative energy during the loading process of recycled modified asphalt and increases the total dissipative energy required for fatigue failure of recycled modified asphalt within a certain range.The index of₅₀ can reflect the change of medium temperature fatigue performance of recycled modified asphalt more comprehensively.With the increase of aging asphalt content,the fatigue performance of recycled asphalt increases first and then decreases.With the increase of the content of warm mix recycled agent,the fatigue performance of recycled asphalt increases first and then decreases.The results of bending beam rheological test show that the addition of aged asphalt weakens the stress relaxation ability of recycled modified asphalt at low temperature,reduces the low-temperature crack resistance,and the addition of temperature mixed recycled agent can effectively restore the low-temperature crack resistance and balance the adverse effect of aged asphalt on the low-temperature performance.It can be seen from the comprehensive change of recycled asphalt performance that the aging modified asphalt can be recycled by using the warm mix recycled agent WL and SBS modified asphalt,which can meet the performance requirements of recycled asphalt under the condition of high aging asphalt content.This method has a wide applicability.Compared with hot mix recycling,warm mix recycling asphalt mixture has better water stability,fatigue performance and low-temperature crack resistance,while hightemperature performance is poor.The application of warm mix recycling technology can increase the RAP content of recycled asphalt mixture to a certain extent.The above experiments and analysis demonstrate the key construction parameters for the actual project,and provide the basic data support for the application of warm mix recycling technology in the recovery of modified asphalt mixture.Among them,the analysis of the performance change of recycled modified asphalt under the coupling effect of aging asphalt and warm mix recycling agent,as well as the discussion on the warm mix effect of recycled asphalt mixture with different content of old material have certain innovation.In the further research,we can choose different principles of warm mix recycling additives,analyze the effect of different recycled old materials,and analyze the application scope of warm mix recycling technology in more detail or explore the influence of temperature change and warm mix recycling agent on the effective recycling rate of aging asphalt in the process of warm mix recycling.