Effects of nanoclay and nanocomposites on bitumen rheological properties

Nanoclays have been successfully introduced into the asphalt, either separated or in the form of polymer/bitumen blends, improving mechanical and rheological properties. In this paper, the organoclay montmorillonite (OMMT) was prepared to be used as an additive for bitumen and for a polymer modified bitumen. A nanoclay Cloisite® 20 Å (CLO), was also investigated for comparison purposes. A bitumen was modified with 4% nanoclays (OMMT and CLO), with 4% SBS, and with 4% SBS/nanoclay. All modified bitumens (MB) exhibited higher G∗ and lower δ, indicating an improvement in the stiffness and in the elasticity. SBS/Nanoclay MB presented similar rheological behavior compared to SBS MB which may result in cost savings. The addition of SBS and SBS/OMMT resulted in increase in PG grade and decrease in non-recoverable creep compliance (Jnr) indicating a better rut resistant compared to pure bitumen.