Fatigue characteristics of nano-SiO2 cemented soil under coupled effects of dry-wet cycle and seawater corrosion

In the marine environment, cement soils are subject to a variety of adverse conditions, including seawater corrosion, dry and wet cycles, and dynamic loading. These environmental conditions pose a significant threat to the structural integrity of these engineered soils. The addition of Nano-SiO2 particles to these cement-treated soils is offered as an engineering solution to extend their service life. It has been shown that the incorporation of Nano-SiO2 into the Cemented soil can significantly increase the static strength and improve the microstructure of the Cemented soil. Four different Nano-SiO2 particles, which have been extensively studied in the literature, are used as admixtures in the cemented-soil. Optimal dosages of these Nano-SiO2 particles are determined based on unconfined compressive strength (UCS) and scanning electron microscopy (SEM) data. Wet-dry cycles are applied to the cement-treated soil samples to simulate tidal rise and fall relevant to the marine environment. Nuclear magnetic resonance (NMR) and X-ray diffraction tests are also performed to complement the SEM study. The incorporation of Nano-SiO2 into cement-treated soils in a marine environment improved the mechanical strength and fatigue life of the cement-treated soils. It also reduced the corrosion rate of the cemented soils in the sea, and the improvement in mechanical stability was also quite remarkable. The fatigue life of Nano-SiO2 cemented soils was 1.35 times longer than that of conventional cemented soils, and the peak dynamic modulus of elasticity of the added Nano-SiO2 cemented soils increased by 29%, when subjected to 60 cycles of seawater. The improved fatigue life of Nano-SiO2 Cemented soils is a function of their structural filling tropism and distribution tropism. The improved fatigue of Nano-SiO2 is a result of the combined effect of particle effect, volcanic ash effect, and nucleation effect.