Physical mechanical properties and microstructure analyses on effect of incorporating cigarette butts in fired clay bricks

Several trillion cigarettes produced worldwide annually lead to many thousands of kilograms of toxic waste. Cigarette butts (CBs) accumulate in the environment due to the poor biodegradability of the cellulose acetate filters. This paper presents some of the results from a continuing study on recycling CBs into fired clay bricks. The results show that the density of fired bricks was reduced by up to 30%, depending on the percentage of CBs incorporated into the raw materials. Similarly, the compressive strength of bricks tested decreased according to the percentage of CBs included in the mix. Nevertheless, by increasing mixing times, better quality bricks can be produced, even with the inclusion of high percentages of CBs. Longer mixing times increased dry density and compressive strength, equivalent to about 53% and 11% respectively. Microstructure observation using ESEM confirm the result by showing the apparent size of pores is reduced drastically and the distribution of pores becomes more uniform as the mixing time increases from 5 to 15 minutes, hence decreasing the porosity in the clay body which subsequently leads to a denser product with higher strength.