Soil reinforcement through addition and subsequent carbonation of wollasonite microfibres

This study describes the application of wollasonite microfibres for stabilising soil with the additional function of sequestering CO₂. The high aspect ratio, needle-like structure of wollasonite imparted a microfibre mechanical reinforcement whilst the associated high surface area promoted carbonation. The originality of this paper lies in two unique aspects: the first stage assessed the efficacy of incorporating wollastonite microfibres inside the soil mass, while the second stage addressed the mechanical performance of the fibre-reinforced soil after different CO₂ pressures and carbonation times. In these two stages, the unconfined compressive strength (UCS), indirect tensile strength (ITS) and flexural strength (FS) were determined. The test results indicated that the inclusion of the fibres increased the peak and post-peak response during unconfined compressive strength (UCS) tests, while also improving the ITS and FS. The UCS peak stress was further improved when the fibre-reinforced soil was subjected to the carbonation process. This work impacts the soil stabilisation industry through a novel soil strengthening process that also promises an effective route to combat climate change through sequestration of CO₂.