Material recyclability: use of discarded eggshells to be recycled into basic building materials

• Main Author: Su, Zen Yong Xuan
• Other Authors: Heng Kok Hui, John Gerard
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Mechanical engineering
• Online Access: https://hdl.handle.net/10356/168364
• Institution: Nanyang Technological University

With the rapidly increasing population around the world, the need for infrastructure to support the number of people has never been higher and is expected to only increase in the future. One of the major components of these buildings is cement. While the basic materials of cement are readily available currently, its large demand does have a significant impact on the environment in terms of the energy required and the carbon emissions generated from the machinery needed to mine and create concrete. A 30 storey flat requires 6000 tonnes of cement to build on average, which produces 4600 metric tonnes of carbon emissions to produce. This is the equivalent of a car driving for more than 1.5 million kilometres. Adding to this is the fact that the amount of cement used in construction can be up to 2-3 times more than what is required due to the cheap cost of procurement, the total amount of carbon emissions resulting from the production of cement adds up to around 8% of total global emissions, and this number can be expected to rise in the future as more developing nations will need to build more infrastructure to support their growth. This report seeks to determine the suitability of eggshells, which similarly to cement, is comprised mainly of calcium and can be obtained easily as a partial substitute in building materials such as cement and concrete. Conceptual design experimentation will be conducted to test the viability of the eggshell cement mix, and should the proposal be viable, proceed to design a machine that will streamline the cleaning and processing of eggshells such that to make the eggshells more suitable to be incorporated into the production of cement. Further explanation on the detailed design will show the rationale of choosing certain material for certain components of the machine as well as elaboration on the mechanical viability of mechanical elements incorporated in the design will also be featured. Eggshell cement mixtures produced of various percentage compositions will then be subjected to further testing on their mechanical properties based on engineering standards that are present in the industry and compared with existing cement mixes such as Portland cement in order to determine the maximum number of eggshells that can be mixed into cement without compromising its mechanical properties. Reducing the amount of cement and replacing it with the maximum number of eggshells would reduce the environmental footprint of the end product.