Air-blown bitumen using grafted silica
View Patent ↗A modified bitumen composition includes bitumen and a multiplicity of silica particles. Each silica particle is coupled to an acid component. Treating a modified bitumen includes contacting the modified bitumen with a flow of air and removing the flow of air after a length of time when a penetration grade of the bitumen decreases to a specified value.
1 . A method of treating a modified bitumen, the method comprising:
contacting the modified bitumen with a flow of air, wherein the modified bitumen comprises:
about 90 wt % to about 97 wt % bitumen;
about 2 wt % to about 6 wt % silica particles; and
about 0.2 wt % to about 2 wt % acid component,
wherein each silica particle is coupled to the acid component, and
a temperature of the air is 170° C.; and
removing the flow of air when a penetration grade of the bitumen is in a range between 50 and 100.
2 . The method of claim 1 , wherein the length of time is between 1 hour and 10 hours.
3 . The method of claim 1 , wherein the acid component enhances intermolecular interactions in the bitumen.
4 . The method of claim 1 , wherein the modified bitumen further comprises additives comprising 3-aminopropyl triethoxysilane (APTES), 3-glycidyloxypropyl trimethoxysilane, or a combination thereof.
5 . The method of claim 1 , wherein the acid component comprises polyphosphoric acid.
6 . The method of claim 1 , wherein the multiplicity of silica particles are nanoparticles.
7 . The method of claim 6 , wherein the nanoparticles have a diameter in a range of about 20 nm to about 30 nm.
8 . The method of claim 1 , wherein the length of time to achieve a penetration grade value between 50 and 100 is shorter for the modified bitumen than for the bitumen.