| In recent years,China’s highway construction speed to slow down,in order to adapt to the growth of traffic demand,a large number of asphalt pavement construction is about to face.Road reconstruction and expansion project will produce a lot of waste asphalt pavement materials,if not to take measures and to recycle,it is bound to cause a huge waste of resources and environmental pollution.The plant mix heat recycling technology can effectively utilize the waste asphalt mixture,but its high discharge temperature and the low content of the old materials greatly limits the performance and regeneration of recycled mixture.Warm mix asphalt mixture technology is hot in plant recycling technology and warm mix technology development based on the new energy saving and environmental protection technology,the lower compaction temperature can effectively alleviate the old asphalt secondary aging and reduce emissions,both solid waste recycling utilization and energy-saving emission reduction,with good prospects for development and the economic and social value.This paper is based on the research on the key technology of the high proportion of recycled asphalt mixture in low temperature environment in Xinjiang,the analysis of the old asphalt mixture performance,asphalt recycling mechanism,Evotherm’s warm mix mechanism based on the study of the mixing of fiber warm mix recycled asphalt mixture compaction characteristics,road performance.Related research contents and conclusions are summarized as follows:First of all,the technical indexes of waste asphalt mixture were evaluated,and the performance recovery test was carried out using the new asphalt and recycling agent.The results showed that:compared with new asphalt,asphalt aging mainly for softening point and viscosity increased,penetration and ductility decrease,the proportion of asphaltene and resin increased,and the proportion of saturated and aromatic fraction decreased,new asphalt to the aging of asphalt mixture regeneration capacity is limited,the amount of HR-1325 recycled agent content range is9.5%-11.5%.Secondly,the design of recycled asphalt mixture was carried out by the reference superpave,s design method,and the compaction characteristics of warm mix recycled asphalt mixture were studied by using the principle of volume ratio.The results show that the Superpave’s design method is suitable for warm mix recycled asphalt mixture,and the performance of the mixed material can meet the requirements of our country;evotherm3G can effectively reduce the compaction temperature of asphalt mixture,in which the hot mixed asphalt mixture can be reduced by about 30 C,recycled asphalt mixture can reduce the temperature of 25℃ ~15℃,its cooling effect and theamount of the old material mixing,cooling effect with the increase of the amount of the old material slightly reduced;fiber will affect the cooling effect of Evotherm warm mix agent,compared with ordinary asphalt mixture,after adding percent 0.3 polyester fiber,the compaction temperature of fiber asphalt mixture increased by 5 ℃ ~10 ℃,too much Evotherm warm mix agent and cannot improve the fiber asphalt mixture compaction effect.Then,the use of indoor experiments to compare the amount of different old materials mixed with hot mix,warm mix recycled asphalt pavement performance.The results show that the high temperature performance of warm mix recycled asphalt mixture is equal to that of the asphalt mixture,which is lower than that of hot mix asphalt,water stability can be slightly lower than the plant mix hot mix asphalt mixture,the performance of warm mix recycled asphalt mixture can basically meet the requirements of the existing specifications,but it should be reasonable to control the amount of the old material,it is necessary to choose to add fiber to make up for the defect of performance.Finally,the economic and social benefits of warm mix recycled asphalt mixture were evaluated.The results showed that: warm mix recycled asphalt mixture reduced waste emissions,saving the cost of production,with good economic and social benefits. |
