Study of fired clay bricks with coconut shell waste as a renewable pore-forming agent: Technological, mechanical, and thermal properties

In the present work, coconut shell powder (CSP) is explored as a pore-forming agent in the manufacturing of fired clay bricks. The bricks were produced by varying the amount of CSP (0, 10, 20, and 30 wt%), and fired at different temperatures (900, 1000, and 1100 degrees C). Mineralogical, physical, mechanical, and thermal conductivity tests were performed to evaluate the properties of the elaborated bricks. It is found that the addition of CSP does not influence the mineralogy of the bricks. Besides, mechanical strength, bulk density, and firing shrinkage increase with sintering temperature and decrease with increasing CSP content, while water absorption and porosity decrease with temperature and increase with CSP addition. Otherwise, the combination of firing at 1100 degrees C with 30 wt% addition of CSP in clay brick provides lower thermal conductivity (0.37 W/(m.K)), while maintaining adequate tensile strength (9.88 MPa). This finding suggests the reuse of CSP as a pore-forming agent to elaborate bricks with thermal insulating character.