Study On Nano-SiO₂-OMMT Compound Modified Asphalt

The demand for asphalt continues to increase and the scarcity of oil resources leads to unsustainable pavement.Due to the increasing demand of society for infrastructure networks.Coupled with economic and environmental constraints,the search for quality asphalt modification materials has become a pressing issue in the development of sustainable road networks worldwide.Nanomaterials are known for their multi-disciplinary applications,especially as pavement materials that improve the aging and adhesion properties of asphalt and asphalt mixtures,and have been found to help improve asphalt rutting,fatigue cracking,aging resistance and spalling properties,as evidenced by their high quality potential properties.In this paper,nano-organic montmorillonite OMMT was compounded with nano-SiO₂for asphalt modification and conventional tests were conducted for physical and rheological properties,while RTFOT,PAV and UV were used to simulate the aging of asphalt and analyze the effect of compounded modifiers on the aging properties of asphalt.The results showed that the incorporation of nano-SiO₂-OMMT compound modifier into asphalt increased the consistency and improved the high temperature stabilization ability of asphalt;the compound modifier had little beneficial effect on the ductility of asphalt within a certain dosing range.The separation test shows that the nano-SiO₂-OMMT composite modified asphalt is more compatible with asphalt than the individual dose of SiO₂and OMMT.in the DSR test,the nano-SiO₂-OMMT composite modifier can significantly improve the complex shear modulus and rutting factor of asphalt,reduce the phase angle,combined with the frequency scan test can be obtained under high temperature conditions,multi-frequency range of the composite modifier still has The MSCR test shows that the incorporation of the compound modifier increases the strain recovery rate and reduces the irrecoverable creep flexibility of the modified asphalt.The BBR test results show that the addition of nano-SiO₂-OMMT compound modifier can slightly improve the low temperature performance of asphalt within a certain doping range.The addition of nano-SiO₂-OMMT compound modifier can reduce the Brinell rotational viscosity growth rate and complex shear modulus aging index of asphalt after RTFOT and PAV aging,improve the phase angle aging index,and improve the thermal and oxygen aging performance of asphalt,with organomontane OMMT playing a decisive role.Accelerated UV aging was used to simulate the photo-oxidative aging of asphalt.The properties of asphalt showed different degrees of degradation after UV aging,but by adding the compound modifier,the Brillouin rotational viscosity aging index and complex modulus aging index of asphalt were significantly reduced,and the improvement of phase angle aging index indicated that nano-SiO₂can reflect UV light well,and its importance in the anti-photo-oxidative aging of asphalt cannot be ignored.Comprehensive modified asphalt physical,rheological and anti-aging properties,3%OMMT+4%SiO₂compound modifier is the best combination.