High and low temperature properties of nano-particles/polymer modified asphalt

• Three kinds of nano-particles/polymer systems were proposed to modify SK-70 asphalt.
• Influences of nano-particles/polymer on the properties of SK-70 asphalt were tested with TFOT, DSR and BBR tests.
• Morphologies of modified asphalts and SK-70 asphalt were measured with SEM.
• The chemical bondings of modified asphalts and SK-70 asphalt were analyzed through FTIR.

At present, most asphalts and modified asphalts cannot meet requirements of both high temperature stability and low temperature cracking resistance simultaneously. Hence, the objective of this paper is to find new modification system to improve the high and low temperature properties of SK-70 base asphalt. In this paper, nano-zinc oxide (nano-ZnO) particles, nano-titanium dioxide (nano-TiO2) particles, nano-calcium carbonate (nano-CaCO3) particles, styrene-butadiene-styrene (SBS) and styrene-butadiene-rubber (SBR) were selected as modifiers. The modified asphalt samples with three or two kinds of modifiers were prepared, and the softening point, ductility and penetration of modified asphalt samples were measured and compared. Eventually, three optimal nano-particles/polymer modification systems for SK-70 base asphalt including 3%nano-ZnO/0.5%nano-TiO2/3.7%SBS, 5%nano-ZnO/4.2%SBS, 5%nano-CaCO3/4%SBR were proposed. To study the effects of these three optimal modification formulations on high and low temperature properties of base asphalt, dynamic shear rheometer (DSR), thin film oven test (TFOT), and beam bending rheometer (BBR) tests were conducted on the asphalt of SK-70 and the nano-particles/polymer modified asphalts. The micro-morphology of SK-70 and the modified asphalts was examined using scanning electron microscope (SEM) and the reactions between modifiers and SK-70 base asphalt were studied by infrared spectrum instrument. From the test results, it was observed that the nano-materials were well dispersed in base asphalt, and could increase the dispersibility of polymer in base asphalt and improve the compatibility between polymer and base asphalt. Furthermore, the nano-materials could improve the high and low temperature properties of SK-70 base asphalt. Additionally, the results also revealed that for polymer modified asphalts the physical reaction between polymers and asphalt played the dominant role in the modification process, while for nano-particles/polymer modified asphalts, both physical and chemical reaction occurred in the modification process.