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Lipstick Gives Roads a Second Life?
14 Oct
Summary
- Expired lipstick oils and waxes may rejuvenate aged asphalt binders.
- Adding lipstick softens asphalt, potentially lowering mixing temperatures.
- Rutting susceptibility at high temperatures is a key concern.
Roads age as bitumen stiffens, leading to cracks and challenges in recycling asphalt. Researchers in South Korea investigated using expired lipstick from a cosmetics store as a potential additive for asphalt binder. Their laboratory study, published in March 2022, mixed lipstick waste into asphalt at 5%, 10%, and 15% concentrations.
These blends underwent accelerated ageing tests simulating short-term production and long-term service. The findings indicated that lipstick softened the asphalt binder, increasing flow and potentially lowering the temperatures required for mixing and compaction. This aligns with warm-mix asphalt principles, offering reduced fuel use and emissions.
Tests also showed that a 5% lipstick blend partially recovered lost ductility after short-term ageing, while higher doses improved ductility after long-term ageing. Infrared analysis suggested a physical, rather than chemical, interaction between the lipstick and asphalt.
A significant limitation identified is that the softened binder with 15% lipstick showed increased susceptibility to rutting at high temperatures. Further comprehensive testing on complete asphalt mixtures and field trials are necessary to assess real-world performance and durability before this novel application can be considered for road construction.
