Effects of long-term aging on the properties of asphalt binder containing diatoms

• Diatomite modified asphalts were prepared by melt blending with diatomite.
• Honeycomb silica structure in modified asphalt can prevent the oxygen.
• Modified asphalt binder with diatomite has better aging resistance.
• The oxygen dispersion in hydrophobic diatomite modified asphalt was harder.

Diatomite modified asphalts were prepared by melt blending with different contents of diatomite and hydrophobic diatomite. The effects of long-term aging on physical properties and chemical structure of the diatomite modified asphalts were investigated. The results show that the viscosity aging index and the increment in the softening point of the modified asphalts decrease significantly with increasing diatomite contents. The retained penetration increases after the introduction of diatomite. The chemical structures of the aged asphalts were evaluated using FTIR. The increased extent of the CO and SO bands areas of the modified asphalt is smaller than that of pure asphalt. The aging resistances of the modified asphalts are much better than that of pure asphalt, because they can efficiently prevent the oxygen, which attribute to the honeycomb silica structure in the modified asphalts. Compared with diatomite modified asphalt, the oxygen dispersion in hydrophobic diatomite modified asphalt was harder, which means the oxidative aging resistance of hydrophobic diatomite modified asphalt was better.