Abstract: Using Karamay No.90 asphalt as a matrix, the modified asphalts by hydrotalcite（LDHs）and waste crumb rubber composite were prepared. The effects of the amount of LDHs on the physical properties, anti-ultraviolet aging performance and rheological properties of the composite modified asphalt were investigated at constant waste crumb rubber amount. The results showed that when the content of waste crumb rubber was 15%, as the addition of LDHs increases, the softening point increased while the penetration and ductility of the composite modified asphalt decreased. It is demonstrated that the integration of two kinds of modifiers improves the physical properties of the composite modified asphalt, and met the requirements of national standard of polymer modified asphalt. Considering the cost of modifying agent, the mass fraction of LDHs added was 3%-4%. The addition of LDHs reduced the softening point increment and increased the residual penetration ratio and ductility retention of the composite modified asphalt, indicating that LDHs can significantly improve the UV aging resistance of the composite modified asphalt. The addition of LDHs can also increase the complex modulus and rutting factor of composite modified asphalt and decrease the phase angle, indicating that LDHs can improve the rutting resistance of composite modified asphalt.

Key words: rubber power, LDHs, composite modified asphalt, anti-aging