Soil microstructure plays a significant role in explaining the observed macro-scale behaviour in geotechnical engineering. Researchers have been utilising the destructive imaging technique (Scanning Electron Microscopy, SEM) to monitor the changes of microstructure of soils. However, due to its destructive nature and absence of insitu loading condition, results obtained from the SEM cannot be considered as representative. Therefore, researchers are encouraged to use an alternative simulation technique (Discrete Element Modelling) to study the effect of microstructural changes on soil behaviour, which again based on ‘digital’ soil particles, and may not simulate ‘true’ soil behaviour. Due to the advancement of high resolution imaging technology, X-Ray Computed Tomography (X-Ray CT) has emerged to be an effective non-destructive 3D imaging technique for monitoring the microstructural changes of soils under insitu condition thus providing an opportunity to explain observed soil behavior using real soil particles.
Improvement of soft soils using environmentally friendly cementitious additives (lime, slag) has been proven to be effective in reducing carbon footprint associated with construction activities. Addition of cementing materials to soft soils enhances strength and deformation properties through the development of time-dependent cementitious minerals which impart structure (bond and fabric) to soils. In this study, the micro-structural changes of lime-slag treated soft soil subjected to insitu condition will be reported. The cured soil sample will be loaded using an insitu unconfined load stage (CT5000). Images at different stages of loading, including pre- and post- peak stress levels, will be acquired and analysed for microstructural changes. The observed microstructural changes will be incorporated in explaining the mechanical behaviour of treated soils. Findings from this study will help to develop a micro-mechanics based constitutive model for treated soils, where soil structure plays a dominant role.