Study on mechanical properties and solidification mechanism of stabilized dredged materials with recycled GFRP fibre reinforced geopolymer

This study used fly ash-slag geopolymer to stabilize silty clayey dredged materials (DM) with recycled glass fibre reinforced plastic (GFRP) fibre. The effects of stabilizer content and fibre content on the mechanical properties of stabilized DM were studied and compared with the reinforced cement stabilized DM. The unconfined compressive strength (UCS) and indirect tensile strength (ITS) of stabilized DM were tested, and the prediction model of bearing capacity was established. The stabilization mechanism was analysed by the microstructural characterization with the scanning electron microscope (SEM). It was found that the post-failure ductility of stabilized DM significantly increased as the content of recycled GFRP fibre increased. When 5 wt% of the fibre was incorporated, both geopolymer and cement stabilized DM reached a maximum strength of 1300kPa and 2200kPa, respectively. As the fibre content further increases, the excessive fibre content would cause agglomeration and deteriorate the mechanical properties. The carbon footprint and cost of geopolymer stabilized DM were reduced by 55% and 26% compared with cement stabilized DM, respectively. This suggests that recycled GFRP fibre incorporated geopolymer provided a potential for being a green DM stabilizer.