Study On Cold Recycling Construction Technology Of Foam Asphalt Plant In Western Chongqing

With the continuous development of the transportation industry,the construction of highway network has been basically improved.For the early construction of high-grade pavement,especially asphalt pavement,under the combined action of vehicle load and climate conditions and other factors,the disease on the pavement is becoming more and more serious,which has seriously affected the driver’s driving comfort and safety.Therefore,most of the high-grade pavement has entered the maintenance and maintenance stage.If the pavement maintenance adopts the traditional overlay technology,it will not only affect the elevation of the existing road,but also lead to poor drainage on both sides of the road;By means of reconstruction,on the one hand,it wastes our country’s precious high-quality asphalt resources,on the other hand,it brings serious pollution to the environment.At the same time,the "12th Five Year Plan","13th five year plan" and the 19 th National Congress clearly pointed out that it is necessary to actively guide and support the recycling and utilization of old pavement materials,and the old pavement materials of large and medium-sized repair and reconstruction projects of expressways and ordinary trunk roads should be reasonably used to comprehensively improve the recycling level of highway pavement materials.Therefore,new technologies,new materials,new processes and new equipment have attracted great attention of scholars at home and abroad.Foam asphalt cold recycling as a new type of pavement recycling technology,not only can effectively recycle the old pavement materials,but also can solve all kinds of disease problems in pavement engineering,and has the advantages of short maintenance cycle and fast open traffic.It is a pavement maintenance technology with broad application prospects.However,most of the current research on this technology is based on the cold recycling equipment of a foreign company.There are many studies on the foaming effect,mixture ratio design and road performance of foamed asphalt cold recycling technology.However,the specific construction technology in practical engineering application has not been clearly described.Thus in the practical application process of foamed asphalt cold recycling technology,there are a series of engineering quality problems such as mixture performance does not meet the requirements,paving segregation,paving cracks,low degree of compaction.Therefore,this paper aims at the application of foamed asphalt cold recycling technology in the lower layer of the road surface reconstruction project in S209 Province of Western Chongqing.Based on the domestic XCL-300 R foamed asphalt cold recycling equipment,the matching construction equipment is selected to carry out the following research work :(1)The milling speed of 5m / min,6m / min and 7m / min is used to mill the old pavement material.According to the indoor screening test,the gradation uniformity of the old pavement material is studied by the dispersion degree of the pass rate curve.(2)According to the dry-wet splitting test and freeze-thaw splitting test,different mixing sequences,mixing time,mixing speed,asphalt volatility and cement content are studied,and the influence of different mixing parameters on the performance of foamed asphalt mixture is analyzed.(3)The paving speed of 3m / min,4m / min,5m / min and 600 r / min,700 r / min,800 r / min,900 r / min and the vibrating speed of the ironing plate vibrating beam are selected.According to the observation method and the measured method,the quality of the layer is analyzed,so that the surface of the foam asphalt mixture has no segregation and cracks,and the flatness and thickness of the layer meet the requirements.(4)Three different rolling methods,rolling times and rolling speed are used to roll the foamed asphalt mixture pavement.The compactness of the pavement is detected by sand filling method,so as to evaluate different rolling parameters.In view of the above aspects of research,the main purpose is to promote the domestic foamed asphalt cold recycling equipment in China and the foamed asphalt cold recycling technology in western Chongqing,and get a set of complete and suitable for the construction technology of foamed asphalt cold recycling in this area.