Assessing the performance of eggshell ash as a sustainable bitumen modifier

Abstract

The disposal of eggshells in landfills presents an ongoing global environmental issue that demands immediate attention. However, a promising solution lies in utilizing eggshells as modifiers in bitumen binders, offering a sustainable approach to alleviating this burden. This study focuses on crushing eggshells to produce eggshell ash, which is then explored as a potential modifier in bitumen binders. The objective is to evaluate the properties of modified bitumen binders incorporating eggshell waste sourced from the food industry and examine their application in bitumen engineering. The optimal weight percentage of eggshell ash in the bitumen is determined, considering four levels (5, 7, 10 and 12%) and two heating temperatures (100 and 200 °C). Several tests are conducted to comprehensively evaluate the eggshell ash, including SEM-EDS and FTIR analyses, providing valuable technical insights into its properties. Additionally, DSR measurements are employed to analyze the characteristics of the bitumen incorporating eggshell ash. The primary oxide group present in the eggshell ash is CaCO₃. Notably, higher concentrations of eggshell ash enhance the resistance of bitumen binders to high temperatures, as indicated by the penetration index results. Furthermore, DSR testing reveals that adding eggshell ash increases the rigidity of the bitumen binders, resulting in improved resistance to deformation.