Silica fume and carbide slag can be used to modify waste mud soil (WMS), which can not only improve the mechanical properties of WMS, but also broaden resource utilization ways of silica fume and carbide slag. For that, in this paper, WMS was modified by adopting 8 % carbide slag and silica fume with different dosages (0, 3 %, 5 %, 7 %, 9 %, and 11 %). Then the small-strain dynamic properties of modified WMS were investigated by using resonance column test, and the microscopic mechanism of modified WMS was analyzed based on Scanning electron microscopy (SEM), Energy dispersive X-ray spectrometer (EDS), Transmission electron microscopy (TEM), X-ray diffraction test (XRD) and Mercury intrusion porosimetry (MIP). It can be found from the resonance column test that the dynamic shear modulus and the damping ratio show an increasing and decreasing trend with the increase of the confining pressure respectively, and both increase with increasing silica fume dosage in the range of 0 to 11 %. A kinetic model applicable to modified WMS was established by introducing the effects of confining pressure and silica fume into the Hardin-Drnevich model. Microscopic testing experiments indicate that there is a reaction between reactive SiO2 in silica fume and Ca(OH)2 in carbide slag, and calcium hydrated silicate (CSH) was generated, which improved the specimen density.

Abiotic stress is characteristic of the semi-arid region, so fertilization with silicon (Si) can mitigate the damage caused by this stress, increasing yield and improving food quality. In this scenario, this study evaluated the agronomic performance and quality of onion bulbs as a function of Si doses in a semi-arid region of Brazil. A field experiment was conducted, designed in complete randomized blocks, testing Si doses (0, 42.6, 83.2, 124.8, and 166.4 kg ha-1), with four replicates. Dry mass, chlorophyll, nutrition, yield, and physicochemical quality of the bulbs were evaluated. Fertilization with Si increased the concentrations of P, N, K, Zn, and Cu in the leaves, indicating an improvement in the nutritional status. There was a decrease in the physicochemical characteristics of the bulbs, such as titratable acidity, soluble solids, total soluble sugars, ascorbic acid, and pyruvic acid, compared to the control. Fertilization with 68 and 72 kg ha-1 of Si, respectively, increased by 10% the commercial yield (81.49 t ha-1) and by 8% the total yield (87.96 t ha-1) of bulbs. The total and commercial yield of onion bulbs is increased with Si doses of 68 and 72 kg ha-1, respectively; however, Si reduces the concentration of physicochemical quality attributes of the bulbs.

This study investigated the impact of optimum dosages of nano-calcium carbonate (nano-CaCO3) and nanosilica on the engineering behavior of black cotton soil. The desired percentage of nano-addition, 2%, for both nanomaterials, was determined by analyzing the plasticity-compaction characteristics and the relative strength index values of treated samples. The study unveiled that the entire clay microstructure was transformed into a nanocrystalline matrix after treatment. The deviatoric strength enhancement with confining pressure and curing period was significant after treating the soil with either nano-CaCO3 or nanosilica. The nanosilica treatment was found to be more effective in improving the California bearing ratio (CBR) strength of black cotton soil samples compared with nano-CaCO3 stabilization. The addition of nanomaterials induced the formation of nanocrystalline hydrate gels and silica gel, resulting in an increased resistance to volumetric deformation under compressive stresses. The hydraulic conductivity of nano-treated samples dropped due to the highly tortuous networks between pores in the nano-crystalline structure. The experimental results were substantiated by analyzing the microstructure of nano-treated soils using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) techniques.

To address the material requirements for grouting reinforcement in fine sand strata, a novel silicate-modified polymer two-component grouting material was designed. In this material, the traditional organic polyol component of the two-component polymer was replaced with an inorganic silicate (water glass) component, along with the addition of tertiary amine catalysts, organotin catalysts, water. The response surface methodology (RSM) was used to statistically predict the performance of the modified polymer grouting material. The effects of four parameters (two-component mass ratio, tertiary amine catalyst content, organotin catalyst content, and water content) and their interactions on response variables (gelation time, polymer solids strength, cemented body strength) were investigated. Based on a comprehensive consideration of various performance requirements for grouting materials in loose fine sand strata, multi-objective optimization was employed to determine the optimal formulation of the modified polymer grouting material (A/B ratio of 0.85, tertiary amine catalyst at 2.48 %, organotin catalyst at 0.63 %, and water at 1.87 %). A series of experimental tests were conducted to evaluate the material properties of the optimal formulation, and its mechanical performance and microstructural characteristics were compared with those of traditional polymer grouting materials to verify the proposed formation mechanism of the modified polymer. The results demonstrated that the proposed design method effectively determines the optimal grouting material formulation. The optimized modified polymer grouting material exhibited excellent comprehensive performance. Finally, the optimized modified polymer grouting material was applied in a pavement repair project on a of a highway. After grouting, the structural layer's uniform integrity was significantly restored, the damaged areas were effectively repaired, the modified polymer slurry showed good diffusion, and the repair effect was satisfactory, meeting the engineering requirements for grouting in loose fine sand strata.

The treatment of soil with biopolymers has demonstrated various benefits, including strength enhancement, reduction in the permeability coefficient, and promotion of vegetation. Consequently, numerous experiments have been conducted to evaluate the strength of biopolymer-treated soils. This study aims to evaluate the interparticle bonding strength attributed to the biopolymer network formed between soil particles, focusing on the strength characteristics at the particle scale. Agar gum, a thermo-gelling biopolymer, was selected to assess the strength of biopolymer solutions. Experiments were conducted at concentrations of 2 %, 4 %, and 6 % with varying drying times to account for the differences in water content. The bonding, tensile, and shear strengths of the agar gum polymer solutions were evaluated under different loading conditions. To compare the strengths and meaningful trends observed in the agar gum polymer solution under different conditions. The results demonstrated that for all strength conditions involving the agar gum solution, the strength increased with higher concentrations and lower water content. During the particle size test, the bonding strength was improved up to 160 kPa, and the tensile strength of the agar gum polymer itself was observed to be up to 351 kPa. Furthermore, the UCS test results of the silica sand mixed with agar gum showed an improvement up to 1419 kPa. Among the evaluated strengths, the tensile strength was the highest, whereas the shear strength was the lowest. A comparison between the adhesive strength tests, which evaluated the strength characteristics at the soil particle scale, and the UCS of silica sand mixed with an agar gum solution revealed a similar trend. The shear strength increased consistently with drying time across all concentration conditions, which was consistent with the trends observed in the UCS. These findings suggest that the strength characteristics of soils treated with agar gum solutions can be effectively predicted and utilized for ground improvement applications.

In this study, ground granulated blast-furnace slag (GGBS) and fly ash (FA) were used as binders, while NaOH (NH) and Na2SiO3 (NS) served as alkali activators. Seawater (SW) was used instead of freshwater (FW) to develop a SW-GGBS-FA geopolymer for solidifying sandy soils. Geopolymer mortar specimens were tested for unconfined compressive strength (UCS) after being curing at room temperature. The results showed that the early strength of the seawater group specimens increased slowly less than that of the freshwater group specimens, while the late strength was 1.16 times higher than that of the freshwater group specimens. Factors including seawater salinity (SS), the GGBS/FA ratio, curing agent (CA) content, and the NH/ NS ratio were examined in this experiment. The results showed that the strength of the specimens was higher for SS of 1.2 %, G90:F10, CA content of 15 %, activator content was 15 %, and NH: NS of 50:50. The pore structure of the mortar specimens was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and computerized tomography (CT), revealing the mechanisms by which various factors influenced the microstructure. XRD indicated that SW-GGBS-FA geopolymer mortar newly produced Friedel salt and calcium silicate sulfate hydrate (C-S-S-H). The microstructures observed by CT and SEM showed that the pore radius of the seawater specimens was mainly less than 10 mu m, and the maximum crack length was 92.55 mu m. The pore radius of freshwater specimens was larger than that of seawater specimens, and the largest crack was 148.44 mu m, which confirmed that Friedel salt and C-S-S-H fill the pores and increase the UCS of the specimens.

Although silicon nutrition in crops has been reported to improve growth and herbicide tolerance, the response of crop-associated weeds has not been studied. To support or reject the hypothesis that silicon nutrition can affect the tolerance of velvetleaf to pyrithiobac-sodium, affecting crop-weed competition, this study was conducted as a dose-response study in which cotton and velvetleaf grown in soil with or without K2SiO3 + silicate-solubilizing bacteria (SSB) were sprayed with pyrithiobac-sodium. Some enzymes involved in lignin biosynthesis, antioxidant, and herbicide metabolism were measured to find physiological changes. The findings accept the hypothesis above for the first time. Silicon nutrition could disrupt pyrithiobac-sodium selectivity for controlling velvetleaf in cotton. Regardless of treatments, velvetleaf accumulated more silicon and lignin than cotton. Unlike phenylalanine ammonia-lyase, the activity of cytochrome P450 reductase (1.3 vs. 0.7 U/g), glutathione S-transferase (1.7 vs. 1.2 U/g), superoxide dismutase (21.7 vs. 12.5 U/mg), and catalase (443.9 vs. 342.5 U/mg) was higher in cotton than in velvetleaf, grown in soil without silicon nutrition. All enzymes became more active with silicon nutrition, but the increase was higher in velvetleaf. In field studies, velvetleaf benefited from silicon nutrition more than cotton, enhancing the competitive ability of velvetleaf in cotton and reducing further crop yield. K2SiO3 + SSB caused a 29.7 % increase in velvetleaf biomass, which caused the greatest damage to cotton seed (80.9 %) and lint (69.2 %) yields. It is recommended to avoid soil nutrition with K2SiO3 + SSB in velvetleafinfested cotton fields, where velvetleaf control with pyrithiobac-sodium is intended.

The brick walls of ancient buildings have got a lot of tiny and closely connected pores inside, so they can soak up water really well. This can easily cause problems like getting powdery and having efflorescence. To stop water from spoiling the grey bricks, this paper focuses on the brick walls of historical buildings in Kaifeng City. Based on our investigation, we study the distribution features of the problems. This paper tells about using the method of negative pressure infiltration to change the grey bricks. We measure all kinds of basic indicators and analyze how different ratios of modifiers affect the water properties and dry-wet cycle tests of the grey bricks. We look at the changes in the inside shape through SEM to show how it changes the grey bricks of ancient buildings. Second, we improve the wet walls by using a way that combines blocking and drainage. The main things we studied and the conclusions are like this: We use sodium methyl silicate and acrylamide polymer as modifiers to soak the historical grey bricks under negative pressure. We figure out the best ratio through orthogonal experiments. We analyze things like the water vapor permeability, how long it takes for a water drop to go through, the compressive strength, the water absorption rate, and the height of water absorption of the modified bricks. The results show that the crosslinking agent and acrylamide monomer have a big influence on how high the capillary water goes up in the modified bricks. The air permeability of the modified grey bricks with acrylamide polymer goes down a bit, but it's still okay. The surface of the modified grey bricks is very hydrophobic and there are fewer pores inside. The mechanical properties of the modified grey bricks get better in different degrees. The water absorption rate and the height of capillary water absorption go down. The modified grey bricks can really cut down the erosion of water on the wall when used in real life. They can reduce salt crystallization and efflorescence caused by rising water, and so make the brick walls of historical buildings last longer. This is super important for protecting historical buildings in Kaifeng City and taking care of other similar structures. Also, by using a way that combines blocking and drainage, and putting polymer infiltration reinforcement and the ventilation of the moisture drainage pipe together, the results show that this combination can really lower the height that capillary water goes up in the brick wall. So we get a way to control how wet the wall is.

Freeze-thaw cycles coupled with sulfate attack represent one of the most challenging service environments for concrete. This study aims to enhance the durability of concrete materials in environments characterized by sulfate attack and severe freeze-thaw conditions. Specifically, it investigates the deterioration laws and evolution models of mortar materials containing silica fume under both freeze-thaw and coupled freeze-thaw/sulfate attack conditions. Mortar specimens with varying silica fume contents (0%, 6%, 8%, and 10%) were prepared and subjected to single freeze-thaw and coupled freeze-thaw-sulfate attack tests to examine the impact of different silica fume dosages on the durability of mortar materials under these harsh conditions. Additionally, a quantitative assessment model for damage evolution was established using the entropy weight method and Wiener process model. The research findings indicate that silica fume significantly enhances the sulfate resistance and freeze-thaw durability of mortar materials, with an optimal dosage of 10%. Within the scope of this study, higher silica fume content results in a greater number of sulfate attack-freeze-thaw cycles the mortar can endure before damage and failure, thereby extending its service life. Based on the Wiener stochastic process damage model and field data, it is predicted that the service life of mortar containing 10% silica fume increases most notably to 36.6 years, representing a relative improvement of 45.8 % compared to mortar without silica fume. These results provide valuable references and guidance for the design and construction of concrete structures in regions characterized by high-cold temperatures and salt- corrosive soils.

The unified effective stress equation based on suction stress, a widely accepted method for calculating effective stress in unsaturated soils, provides a closed-form solution that enables the characterization of soils in both saturated and unsaturated states. The effect of desaturation on the water content of natural and treated soils was studied with respect to unconfined compressive strength (UCS) and indirect tensile strength (ITS). The soil's moisture-dependent behavior was characterized by the van Genuchten (Soil Sci Soc Am J 44:892-898, 1980. https://doi.org/10.2136/sssaj1980.03615995004400050002x) and Lu et al. (Water Resour Res, 2010. https://doi.org/10.1029/2009wr008646) models and implemented using the equation. Suction tests were conducted using the dew point and filter paper methods, alongside UCS and ITS tests, on silty clay soil and microsilica-treated soil with microsilica contents of 5%, 10%, and 15%. The equation was validated by comparing mean total stress (p) and mean effective stress (p ') to deviatoric stress (q) and analyzing the friction angle at different suction levels. It proved applicable to both natural and treated soils, with valid moisture content ranges of 4-17.5% and 6-20%, respectively. This study experimentally confirms the equation's effectiveness in characterizing the hydro-mechanical behavior of soils under varying moisture conditions.