Experimental studies on reinforcing aeolian sand with cement and fiber are lacking, and the interface mechanism and splitting characteristics thus remain unclear. Herein, the interface mechanism and splitting characteristics of fiber-reinforced, cement-solidified, aeolian sand were experimentally assessed to investigate whether glass fiber exhibits better properties as a reinforcing agent than traditional fiber-free cement-solidified aeolian sand, and whether aeolian sand is applicable as a base material in geotechnical engineering. The splitting experiments involved the use of fiber-reinforced, cement-solidified aeolian sand samples that were differentiated based on the mixing schemes used to formulate them. Based on the strengthening control technology effects on the structural performance of the fiber-reinforced, cement aeolian, sand-mixed matrix material, the internal physical and chemical mechanisms of structural performance evolution were revealed and analyzed using scanning electron microscopy images. The experimental results show that the splitting strength of the sample reaches its maximum value at a combination of 6 mm glass fiber, 3‰ fiber, and 10% cement contents. In fiber-reinforced cement-solidified aeolian sand, cement hydrate forms more needle-shaped crystal products. The crystals adhere to the fiber surfaces that interweave with each other to form a porous and dense network. Although this improves the bonding force between the fiber and aeolian sand particles, the fibers are prone to fracture and slippage during the splitting process. The three-dimensional network structure formed by overlapping fibers is critical for the improvement of the splitting strength. The study’s findings will serve as benchmarks to achieve additional improvements in glass fiber-reinforced cement-solidified aeolian sand.

This paper puts forward a new soft soil reinforcement technology—microbial-induced calcite precipitation (MICP) technology—which considers the problem of dredger fill soft-soil reinforcement in Dalian Taiping Bay. In this paper, the calcium carbonate content (CCC) and unconfined compressive strength (UCS) of microbial solidified dredger fill (MSDF) samples were determined using laboratory experiments. The microstructure and chemical composition of MSDF samples were studied by SEM–EDS and XRD. The failure and reinforcement mechanism of MSDF under different experimental conditions (ambient temperature, cementation solution concentration, and clay content) were investigated. The results showed that there was a certain residual strength after the peak strength of MSDF. With the increase of ambient temperature, the number of microorganisms increased, but the activities of urease, CCC, and UCS decreased. The UCS and CCC increased with the increase of cementation solution concentration, while they first increased and then decreased with the increase of clay content. The clay content enhanced the compactness of MSDF samples but reduced the soil permeability and weakened the mineralization. There were significant differences in the morphology of microbial-induced precipitation caused by different concentrations of cementation solution.

In order to study the influence of freeze–thaw cycles on chloride ion corrosion resistance of RPC with copper slag (CS) instead of quartz sand (QS), the 28d uniaxial compressive strength (UCS) of CSRPC with a different CS substitution rate was investigated by unconfined compression tests. The electric flux test method was used to study the chloride ion diffusion resistance of CSRPC after freeze–thaw cycles, and the pore size distribution was obtained through the nuclear magnetic resonance (NMR) method. Then, a mathematical relationship between the chloride ion diffusion coefficient and the pore fractal characteristic parameter T was established to study the effect of freeze–thaw cycles on chloride ion diffusion. Finally, SEM/EDS, XRD, and DTG methods were combined to study the influence of the distribution of Friedel’s salts generated after freeze–thaw cycles on chloride ion diffusion in CSRPC. The results indicate that CS has a micro aggregate effect and pozzolanic activity, which can effectively improve the chloride ion diffusion resistance of CSRPC after freeze–thaw cycles. In addition, the electric flux of CSRPC decreases with the increase in freeze–thaw cycles, and the chloride diffusion coefficient is closely related to the pore fractal dimension.