Study On Application Technology Of Plant Mixing Hot Recycled Asphalt Mixture

The recycling technology of asphalt mixture can effectively use the old materials,especially the widely used plant heat regeneration technology,which can not only achieve the purpose of saving resources and protecting the environment,but also obtain high quality recycled asphalt mixture.However,there are still many problems in the degree of mixing of new-old asphalt in hot reclaimed asphalt mixture and the quality control of pavement caused by temperature segregation during the construction of mixed pavement.In order to promote the miscibility of new-old asphalt in hot reclaimed asphalt mixture and improve the performance of hot reclaimed asphalt mixture,this paper introduces the index to evaluate the degree of transfer of aged asphalt from the perspective of macroscopic test,and studies the mixture through orthogonal test.The mixing conditions(RAP preheating temperature,mixing time,effective asphalt film thickness,etc.)have an effect on the degree of transfer of aged asphalt.Through the test results,the comprehensive test results are predicted,and the influence of various factors on the transfer degree of the old asphalt is further analyzed.Through the research on the mixing sequence of hot reclaimed asphalt mixture at home and abroad,two mixing sequences are selected according to the timing of new asphalt addition.The new asphalt is marked by the tracer,and the RAP and the new aggregate are mixed under the different order of addition of the new asphalt.After the mixing,the RAP is separated according to the particle size,and the tracer is observed by SEM electron microscopy.The depth of distribution of the asphalt layer section to calculate the degree of miscibility of the new-old asphalt.According to the mixing conditions obtained in the above test,the conventional and optimized two mixtures were tested for high,low temperature and water stability,and compared with the performance of conventional hot reclaimed asphalt mixture,the static stability was slightly lower.In addition to the conventional mixing sequence,the low temperature and water stability are superior to conventional hot reclaimed asphalt mixtures.Finally,according to the above research conclusions,the preparation process of the mixing material in the mixing station is adjusted,and the temperature of the mixed asphalt mixture in the project is analyzed by the infrared thermal imaging research institute.Combined with FLIR software and MATLAB software,the influence of rolling process on the temperature separation area of recycled asphalt pavement was studied,and the key parts were supplemented and compacted.The non-nuclear density meter was used to detect the situation before and after the compaction of the isolated area.The compaction degree was visualized by MATLAB,and it was found that the compaction degree was low in the area where the temperature was separated.After the surface of the road surface is positioned by the infrared thermal image,and the compaction is performed by the roller,the road surface compaction degree is improved.It is feasible and effective to use the infrared camera to control the quality of the road surface caused by temperature segregation.