Research On Performance And Damage Evolution Of Basalt Fiber Asphalt Mixture With Different Diameters

Basalt fiber asphalt mixture has excellent resistance to high-temperature deformation,low-temperature cracking,freeze-thaw damage and fatigue cracking.In recent years,it has been widely used in highways,national and provincial trunk lines,and urban expressways.The characteristic parameters of basalt fiber(including length,diameter,etc.)are important factors that affect its reinforcement in the mixture.Existing researches have proved the adaptability of fiber length and asphalt mixture gradation,but the research about the impact of the fiber diameter on asphalt mixture is still lacking.Therefore,this article intends to study the influence of different diameters of basalt fiber on the performance of asphalt mixture,especially the crack damage evolution of the corresponding mixture.Firstly,three different diameters of basalt fibers of 7μm,13μm and 25μm were selected.Basalt fiber AC-13 and basalt fiber SMA-13 were designed through the Marshall test design method.The results show that as the diameter of the basalt fiber increases,the best oil-stone ratios of the AC-13 and SMA-13 gradations decrease slightly.Secondly,the rutting test,uniaxial penetration test,low-temperature trabecular bending test,IDEAL cracking test,semicircular bend geometry test,water immersion Marshall test,freeze-thaw splitting test and dynamic modulus test were used to determine the road performance and mechanical properties of basalt fiber asphalt mixture.The results show that,compared with conventional no fiber AC-13 or SMA-13 mixed with lignin fiber,the addition of basalt fiber could improve the high-temperature deformation resistance,low-temperature resistance and medium temperature cracking performance of the asphalt mixture.The basalt fiber with a diameter of 7μm has the most prominent reinforcement effect on the asphalt mixture,while the basalt fiber with the diameter of 13μm or 25μm has the same reinforcement effect,and both are inferior to the 7μm.Besides,after adding basalt fiber,the water stability of the asphalt mixture does not change much.Finally,based on the semicircular bend geometry test,digital image correlation(DIC)technology was used to capture the full-field displacement of the asphalt mixture specimen during the crack occurrence and development process,and calculate the real-time orthogonal displacement of the crack tip field,the average expansion speed(V)and the corresponding dynamic fracture characteristic parameters were proposed.The results show that,compared with conventional AC-13 or SMA-13,basalt fiber can greatly retard the crack propagation speed of asphalt mixture.Among them,the basalt fiber with a diameter of 7μm has the best retarding effect on the crack propagation speed of asphalt mixture.The basalt fibers of 13μm and 25 μm have similar retardation effects,and both are inferior to those of 7μm.In this paper,road performance and mechanical properties of basalt fiber asphalt mixtures with different diameters are studied.Crack damage evolution law is deeply analyzed based on the DIC technology.The results can provide a useful reference and reference for the application of basalt fiber with different diameters on asphalt pavement.