The concept of circular economy has become one of the key components in modern-day construction practice, promoting resource efficiency by reducing and reusing waste materials. The focus of this concept is to achieve sustainability in the construction industry by reducing adverse environmental impacts, especially in manufacturing raw materials such as cement, aggregates, steel, etc. This study focuses on producing an efficient and sustainable alternative for natural aggregate-based stone columns to use in ground improvement applications. Similarities in most of the physical and mechanical properties between natural aggregates and recycled waste glass (RWG) aggregates enable to use of RWG aggregates for stone column-based ground improvement. Even though RWG enhances the sustainability of the construction process, the limitations of traditional stone columns on weak soft soil layers remain the same. The bulging failure of unbound stone columns under serviceability conditions is common due to inadequate lateral support in soft ground conditions. This issue needs to be addressed to enhance the performance of columns. This study proposes a glass powder (GP) based, sustainable geopolymer binder to be used with RWG aggregates to enhance the performance of the column-based ground improvement approach. The high amorphous silica content in ordinary soda lime glass (bottle glass) makes it an ideal precursor material in the geopolymerisation process. The aluminium deficiency in GP needs to be provided in terms of an external source, and waste aluminium foil (AF) was selected as a sustainable aluminium source in this study. Sodium hydroxide (NaOH) was employed as the alkaline activator in this study at different molarities. The development phase of the RWG-based new composite was carried out in stages considering six control parameters: (i) particle size distribution of RWG aggregates, (ii) Sodium to Aluminium pre-dissolving ratio, (iii) liquid to solid ratio, (iv) NaOH molarity, (v) curing temperature and (vi) curing period. Unconfined compressive strength (UCS) of the composite produced in each trial was used to obtain the optimum material combinations and the curing conditions. The formation of alkaline aluminosilicate (N-A-S-H) in the optimised binder was investigated using scanning electron microscopy images and X-ray diffraction patterns.
A novel approach for stone column supported embankments using chemically stabilised recycled glass
Kariyawasam Kankanamge, W. P. (Author). 2025
Western Sydney University thesis: Doctoral thesis