Research On Cold Regeneration Technology Of Foamed Asphalt

In the process of asphalt pavement construction,the recycling of waste asphalt pavement materials can greatly improve the utilization rate of resources.This is in line with the strategic core goals and tasks proposed by the National "The 13 th Five-Year Plan" and the Environmental Resources Protection Plan to accelerate the completion of our national ecological environmental protection technology short board.The use of foamed asphalt to stabilize waste asphalt mixture can greatly reduce energy consumption and environmental pollution.Therefore,it is of great significance to study the cold regeneration technology of foamed asphalt.Based on the reconstruction and expansion project of the Changchun to Lalin River section of the Jingha Expressway,this paper studies the preparation of foamed asphalt,the performance of RAP asphalt recovery,the design and verification of the target mix ratio of recycled materials,and the environmental benefits of cold recycling of foamed asphalt.The content is as follows:Using the German-made WLB10 S foaming machine to carry out the foaming test on the matrix asphalt,the effect of asphalt temperature,type,label,foaming water consumption,foaming agent on foaming effect was studied.The results showed that the foaming water consumption and the label of asphalt have a greater impact to and foaming,and the incorporation of the foaming agent can significantly increase the half-life.The old materials of RAP are collected in different work areas using milling equipment,and their gradation characteristics are studied.It was found that the milling speed and the gradation of the original pavement had a greater influence on the gradation of the milled material.The base tests,dynamic shear rheometer(DSR)test and bending beam rheometer(BBR)test were conducted to characterize the rheological behaviors of SBS modified asphalt,PAV aging SBS modified asphalt and RAP extracted asphalt.The study found that the internal viscous components of the asphalt increased significantly after aging,and the high temperature rheological properties and low temperature creep properties deteriorated.Based on the target mix design method of the water stability of the reclaimed material and the performance of the extracted asphalt,the maximum dry density obtained by the compaction test is used to determine the optimal mixing and pressing water consumption of the reclaimed material.The wet splitting strength of the recycled material and the dry-wet splitting strength ratio are used as the controlling index to determine the optimal amount of foamed asphalt.Finally,the mechanical properties,high-temperature stability and water stability of the target mix ratio of the recycled material are verified.Finally,by comparing the energy consumption and carbon emissions generated by the cold regeneration of foamed asphalt and the traditional hot-mixed asphalt pavement during the road construction process,the results show that the energy consumption and carbon emissions generated by the cold regeneration of foamed asphalt are significantly lower,indicating that the technology has better environmental protection benefits.