Civil engineering researchers in Australia have finally come up with a constructive use for the world’s several trillion cigarette butts discarded each year.
According to the latest issue (164 CM5) of ICE’s journal Construction Materials, used cellulose acetate filters can be successfully and safely recycled by making them into lightweight, insulating building bricks.
Tons of butts
Over 5.5 trillion cigarettes were produced worldwide in 2004 resulting in an estimated 17 million tons of cigarette butts. This figure is expected to increase more than 50% by 2025. The butts are not only slow to biodegrade, but also contain hundreds of toxic chemicals and heavy metals from cigarette smoke, at least 60 of which are known to be carcinogenic.
Can butts become bricks?
Lead author Aeslina Kadir of RMIT University in Melbourne describes how difficult recycling cigarette butts can be. There is no easy way to ensure efficient and economical separation of the butts and then there’s the issue of treating the trapped chemicals. She goes on to suggest incorporating cigarette butts “in a building material such as fired bricks”.
A series of trials using cigarette butts and clay resulted in bricks that were up to 30% lighter and with 58% lower thermal conductivity. While testing reduced compressive strengths, longer mixing times significantly improved this and flexural strength changed little. Leachate tests showed only trace amounts of heavy metals after 134 days, so the toxic content was safely locked away.
A sustainable solution
Co-author Abbas Mohajerani concludes that, “recycling cigarette butts in bricks is a very practical and potentially significant contribution”. This offers a sustainable solution to a serious environmental problem.
Find out more
For further information please contact the ICE Proceedings editor Simon Fullalove on +44 (0)20 8744 2028 or email email@example.com