Research On The Micro-nano Characteristic Of Basalt Fiber And The Interfacial Property With Asphalt Mortar

Asphalt pavement is the main pavement form of high-grade roads in China.With the rapid development of highway construction in China,the overall level of asphalt pavement has been greatly improved.However,the increasing traffic load and extreme environmental conditions put forward higher standards for the performance of asphalt pavement materials.Lots of scientific research and engineering practice show that compared with asphalt/modified asphalt mixture,basalt fiber asphalt mixture shows more comprehensive performance advantages.However,basalt fiber surface is smooth and chemically inert,and the adhesion performance with asphalt is insufficient,which leads to the failure of fiber function.Therefore,in this paper,the silane coupling agent KH-550 was used to control the micro-nano characteristic of basalt fiber surface,and the rheological property and adhesion ability of basalt fiber asphalt mortar under the corresponding conditions were studied to establish the relationship between the rheological property and adhesion ability of basalt fiber asphalt mortar.Firstly,the micro-nano characteristic of basalt fiber surface before and after modification were analyzed by field emission scanning electron microscopy,fourier transform infrared spectrometer,video optical contact angle measurement,X-ray energy dispersive spectroscopy and other microscopic characterization methods.The results show that:the surface of modified basalt fiber is rougher,and the siloxane groups are formed on the surface of the fiber,which improves the surface energy of fiber and its adhesion work with asphalt,and is more conducive to the adhesion between asphalt and fiber.Increasing the concentration of the silane coupling agent solution and the modification time can promote the surface reaction.When the concentration exceeds 2.0%and the modification time exceeds 30 min,the reaction degree slows down.Secondly,the asphalt mortar with modified basalt fiber,asphalt mortar with unmodified original fiber and asphalt mortar without fiber were prepared.The effects of different control parameters on the rheological property of basalt fiber asphalt mortar were studied by dynamic shear rheological test and bending beam rheological test.The results show that:the addition of basalt fiber can effectively improve the high-temperature rheological property of asphalt mortar.Compared with the original basalt fiber,the modified basalt fiber has more significant effect on improving the anti-deformation ability and creep recovery ability of asphalt mortar.Compared with the original basalt fiber,the modified basalt fiber can improve the low-temperature rheological property of fiber asphalt mortar.When the concentration is 2.0%,4.0%and the modification time is 30min～ 60min,the rheological property of fiber asphalt mortar is similar.Then,the pull-out test of fiber asphalt mortar was designed to test the adhesion ability of basalt fiber and asphalt mortar before and after modification,and the influence of fiber surface control parameters on the maximum tensile force(Fmax)and pull-out work(WL)was analyzed.The results show that:compared with the original sample fiber,the Fmax and WL of modified basalt fiber asphalt mortar have been greatly improved,and the trend increases with the increase of concentration and modification time,indicating that the modified basalt fiber and asphalt have better adhesion ability,which is more conducive to the fiber "reinforcement" and "bridging" role.Finally,the relationship between rheological property and adhesion ability of basalt fiber asphalt mortar is analyzed.The results show that:the high-temperature and low-temperature rheological property of basalt fiber asphalt mortar have a certain correlation with the interfacial adhesion ability,and are affected by temperature.Among the evaluation indexes of high-temperature rheological property,the irrecoverable creep compliance has the best correlation with the interfacial adhesion ability,that is,the stronger the interfacial adhesion ability is,the smaller the irrecoverable creep compliance is,and the stronger the anti-deformation ability of fiber asphalt mortar is.The correlation between creep rate m and interfacial adhesion ability of fiber asphalt mortar is better than creep stiffness modulus S.On the whole,the correlation between high-temperature rheological property and interfacial adhesion ability is better.The trend of the correlation between the interaction parameter B and the interfacial adhesion ability is similar to that of the rheological property at high temperature.At 52 ℃,76℃ and 82℃,the higher the interfacial adhesion,the stronger the interaction between fiber and asphalt mortar.The research can provide a reference for the control of micro-nano characteristic of basalt fiber surface,and provide a scientific basis for the performance research of basalt fiber asphalt composites.