Study on Flame Retardant Performance of Modified Asphalt Based on Functional Groups and Thermogravimetric Analysis

Abstract

In order to clarify the flame retardant mechanism and microscopic performance of modified asphalt, a new inorganic flame retardant was prepared using three flame retardants, and antimony trioxide and decabromodiphenyl oxide were selected for comparative testing. Twelve groups of asphalt samples were prepared as research materials, including eight groups of short-term and long-term aging samples. The effects of different types of flame retardants on the performance of modified asphalt were compared by macroscopic performance test, infrared spectroscopy and thermogravimetric analysis. The changes in functional groups of asphalt samples before and after aging were studied. The mass loss before and after aging was analyzed, and the flame retardant modes of various types of flame retardants were explored. The results showed that the functional groups of asphalt were not altered by the inorganic flame retardant and antimony trioxide. Both flame retardants were physically mixed with the modified asphalt. The hydrogen ions in the unsaturated bond C═C were partially replaced by bromine ions of decabromodiphenyl oxide, indicating that a chemical reaction occurred. The basic properties of modified asphalt were well maintained by the inorganic flame retardant; the formation of carbonyl groups was reduced, and the oxidation reaction during aging was also alleviated. In the combustion of inorganic flame retardants and decabromodiphenyl oxide, gas molecules were decomposed, oxygen concentration was reduced, and oxide-coated asphalt was formed. In contrast, only oxide-coated asphalt was formed in the combustion of antimony trioxide. Therefore, the study provides an approach to improve the aging resistance and pavement performance of flame retardant–modified asphalt, and also demonstrates its potential for practical applications.