The flammability and theological behavior of asphalt modified by mixed flame retardants was investigated using differential scanning calorimetry and dynamic shear rheometer, respectively. The mixed flame retardants used consisted of decabromodiphenyl ether, antimony trioxide and aluminium trihydroxide with the ratio of 3: 1:1 by mass. Experimental results indicated that the inclusion of 6 wt%. mixed flame retardants improves the flame retardancy significantly by consuming the released heat of asphalt in a temperature range of 300-500 degrees C. The close values of the activation energy obtained by fitting Arrhenius model demonstrate flame retardant modified asphalt exhibits similar thermal susceptibility to base asphalt in the temperature range of 30-100 degrees C. It can foresee that the content of flame retardant is expected to increase with respect to better flame resistance if required based upon this research. (c) 2007 Published by Elsevier Ltd.