Study On Performance Of Fiber-Rubber Particle Asphalt Concrete

Since the beginning of the new century,China's road construction has been in a state of rapid development.It has stimulated the development of the transportation industry.At the same time,it has produced a large number of non-degradable waste rubber tires,causing serious black pollution.Waste rubber tires have high elasticity and corrosion resistance.If they are broken into particle and incorporated into asphalt concrete,they can improve the road performance of asphalt concrete and consume a large amount of used tires.Therefore,rubber particle asphalt concrete has become a way to make rational use of used rubber tires.Polyacrylonitrile fiber has the characteristics of stable chemical properties,and less swelling.It has a good modification effect on rubber particle asphalt concrete.In this paper,rubber particle asphalt concrete is modified by incorporating polyacrylonitrile fiber.Firstly,based on the theory of step-by-step filling and particle interference theory,the optimized CAVF method is used to design the mix ratio of rubber particle asphalt concrete,and the best oil-stone ratio is tested by relevant tests.Secondly,different amounts of polyacrylonitrile fiber are externally mixed.The concrete road test indicators are analyzed to evaluate the modification effect of different fiber and rubber particle on asphalt concrete.Finally,according to the fractal theory,the segmentation fractal dimension value Dc and rubber particle asphalt concrete are established.The fitting relationship of each road use index gives the suggested value of the segmentation dimension value Dc.The research results show that the optimized CAVF method can better predict the best oil-stone ratio,and the designed rubber particle asphalt concrete Marshall test index also meets the standard value.Asphalt concrete with four different rubber particles showed good temperature stability and anti-sliding properties,but the water stability decreased with the increase of rubber particles;after mixing polyacrylonitrile fiber for rubber particle asphalt concrete,the road performance has been improved to varying degrees,especially for the improvement of water stability.According to the performance of each road,2% of rubber particles and 0.3% of polypropylene fiber have the best modification effect on asphalt concrete,high temperature stability can be improved by 39.1%,low temperature stability can be improved by 34.3%,and resistance is improved.Sliding stability can be increased by 3%,and water stability is basically unaffected.Applying fractal theory and according to the requirements of various road specifications,it is recommended that the Dc value of rubber particle asphalt concrete should be in the range of 1.72~2.2.