Study On Properties Of Basalt Fiber Asphalt After Acid And Alkali Erosion

Basalt fiber is a new kind of environmental mineral fiber.With high tensile strength,high elastic modulus,high temperature resistance,corrosion resistance and no aging,it is an excellent pavement reinforced material.Adding basalt fiber into asphalt,making it a fiber-reinforced composite material,which is the development direction of durable road.However,the basalt fiber is mineral fiber,presenting a regular cylindrical shape,smooth surface,and the bonding effect of basalt fiber and asphalt is not ideal,low oil absorption rate.So this paper mainly studies the improvement of basalt fiber and asphalt interface for acid and alkali erosion and the performance of basalt fiber asphalt.In this paper,the micro appearance,surface functional groups and Si content of the fiber before and after acid and alkali erosion were analyzed by environmental scanning electron microscopy(ESEM),infrared spectroscopy(FTIR)and elemental energy dispersive spectrometer(EDS),determining the interface improvement principle of the fiber and the asphalt before and after acid and alkali erosion and reasonable combination of erosion process.The properties of the fiber before and after erosion were investigated by ESEM,heat resistance test and holding capacity test.The results showed that the basalt fiber after corrosion improves the adhesion of fiber and asphalt obviously,improved the holding capacity of asphalt absorption obviously,increased by 13.7%compared with the original fiber,but have little effect on heat resistance,mass loss was less than 1%.The best combination of acid and alkali erosion process basalt fiber erosion is the solution:NaOH,concentration:2.5mol/L,time:45min.Basalt fiber asphalt was prepared by basalt fiber and SBS modified asphalt before and after acid and alkali erosion.The conventional performances of the fiber asphalt were studied by softening point test,force-ductility test at 5℃,elastic recovery test,Brookfield viscometer test and segregation test.By dynamic shear rheometer(DSR)test and low-temperature bending beam rheometer(BBR)test,the rheological properties of fiber asphalt were studied.The results show that the softening point,elastic recovery and the Brookfield viscometer of the fiber asphalt were improved than that of the original fiber asphalt after the alkali erosion.And the softening point increased 3.5℃,the elastic recovery increased to 68.462%,the Brookfield viscosity increased 1.01Pa·s.The ductility at 5℃ has little difference,but the maximum tensile stress increases obviously,and the increase amount is as high as 29.6N.The segregation of the fiber asphalt is improved obviously.From the dates of Complex modulus G*,phase angle δ,rutting factor G*·sin-1δ,storage modulus Gs,viscosity,creep stiffness S and creep stiffness change rate m,the high and low temperature rheological properties of the fiber asphalt were improved.With the increase of acid erosion concentration and time,the performance of fiber asphalt increased first and then decreased.It is reasonable to verify the optimal combination of erosion.The research results can provide the basis for improving the treatment method of interface between basalt fiber and asphalt,and provides important reference for the popularization and application of basalt fiber in our country.