Investigation of low-temperature properties of diatomite-modified asphalt mixtures

The laboratory experiment results of diatomite modified asphalt mixtures are inconsistent with the observed results of the trial road. To find the reason of this, Scanning Electron Microscope (SEM), Differential Scanning Calorimetry (DSC), Infrared Spectroscopy (IR), Dynamic Mechanical Analysis (DMA), beam bending test, uniaxial compression test, Thermal Stress Restrained Specimen Test (TSRST) and Thermal Conductivity (TC) tests are employed to evaluate the low temperature performance of diatomite-modified asphalt mixtures and investigate the modified mechanism of diatomite. Three types of mixtures, including diatomite modified asphalt and neat asphalt, are used in this research. The analyses of test results show that Changbai and Linjiang diatomite particles distribute well in asphalt and no new functional group generated after adding diatomite into asphalt, and the thermal physical properties of asphalt mixture are changed. From these mechanical tests results it can be found that diatomite-modified asphalt mixtures have the better low temperature performance than neat asphalt mixture.

► Thermal physical characteristics of asphalt mastic can be changed by diatomite.
► No new functional groups generated after adding diatomite into asphalt.
► Diatomite can improve low temperature performance of mixture.