Next Article in Journal
Electromyographic Analysis of Lower Limb Muscles During Multi-Joint Eccentric Isokinetic Exercise Using the Eccentron Dynamometer
Previous Article in Journal
Transfer Learning-Based Detection of Pile Defects in Low-Strain Pile Integrity Testing
 
 
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Synthesis of Thermo-Responsive Hydrogel Stabilizer and Its Impact on the Performance of Ecological Soil

1
China Yangtze Power Co., Ltd., Yibin 644612, China
2
College of Civil and Transportation Engineering, Hohai University, Nanjing 210098, China
*
Authors to whom correspondence should be addressed.
Appl. Sci. 2025, 15(15), 8279; https://doi.org/10.3390/app15158279
Submission received: 17 June 2025 / Revised: 21 July 2025 / Accepted: 22 July 2025 / Published: 25 July 2025
(This article belongs to the Section Ecology Science and Engineering)

Abstract

In high-slope substrates, special requirements are imposed on sprayed ecological soil, which needs to exhibit high rheological properties before spraying and rapid curing after spraying. Traditional stabilizers are often unable to meet these demands. This study developed a thermo-responsive hydrogel stabilizer (HSZ) and applied it to ecological soil. The effects of HSZ on the rheological, mechanical, and vegetation performance of ecological soil were investigated, and the mechanism of the responsive carrier in the stabilizer was explored. The experimental results show that the ecological soil containing HSZ has high flowability before response, but its flowability rapidly decreases and consistency sharply increases after response. After the addition of HSZ, the 7 d unconfined compressive strength of the ecological soil reaches 1.55 MPa. The pH value of the ecological soil generally ranges from 6.5 to 8.0, and plant growth in a simulated vegetation box is favorable. Conductivity and viscosity tests demonstrate that the core–shell microcarriers, upon thermal response, release crosslinking components from the carrier, which rapidly react with the precursor solution components to form a curing system. This study provides a novel method for regulating ecological soil using a responsive stabilizer, further expanding its capacity to adapt to various complex scenarios.

1. Introduction

Soil stabilizers, as critical functional materials in modern geotechnical engineering, enhance macroscopic soil properties by reconstructing microstructures through synergistic mechanisms including physical filling, chemical bonding, and biomineralization [1,2,3]. The stabilization mechanisms primarily involve interfacial reactions such as ion exchange, cementitious phase formation, and interparticle bonding networks, which significantly improve compressive strength, shear resistance, and water stability. Traditional systems have been widely applied in subgrade engineering, contaminated soil remediation, and soft foundation treatment, particularly for silt and clay improvement [4,5,6]. However, these systems face significant challenges in specialized scenarios like high-slope revegetation and mine ecological restoration.
In steep slope restoration, sprayed eco-soil technology is widely adopted for its operational efficiency but suffers from a critical performance paradox: the slurry must maintain high fluidity during pumping for uniform coverage yet rapidly solidify post-spraying to form stable structures. Conventional stabilizers often cause pipeline blockages or slope slippage due to uncontrolled curing kinetics. Alternatives like mesh-hanging and hydroseeding exhibit low vegetation survival rates, high costs, and ecological disruption from blasting [7,8,9,10,11]. These limitations underscore the urgent need for intelligent stabilization materials [12,13,14,15].
Current soil stabilizer systems can be classified into four categories based on their mechanisms: (1) Inorganic systems: Form cementitious matrices through hydration reactions that generate calcium silicate hydrate gels. (2) Ionic systems: Achieve stabilization via cation exchange-induced compression of double electric layers. (3) Organic polymer systems: Create spatial networks through polymer chain entanglement. (4) Bio-enzymatic systems: Enhance soil density by catalyzing clay mineral reorganization [16,17]. While these systems perform well in specific scenarios, they still exhibit critical limitations: (1) Uncontrolled release processes hinder dynamic modulation of soil properties. (2) High energy consumption during production and secondary ecological issues. (3) Limited environmental responsiveness to complex conditions like wet–dry cycles and freeze–thaw alternations [18,19]. These challenges motivate the development of intelligent, ecocompatible materials. Hydrogel systems have recently attracted significant attention due to their controllable phase transitions and environmental friendliness. He et al. [20] demonstrated that thermo-responsive hydrogels enhance soil water retention and erosion resistance. Mengxue G et al. [21] developed a hydrogel system with rapid curing capabilities. Qi Z et al. [22] reduced stabilizer response time from hours to minutes via microencapsulation-controlled release technology. Zhao Z et al. [23] proposed a high-strength hydrogel stabilizer system for soil applications. Responsive technologies can equip eco-soils with multifunctionality to better adapt to environmental stresses. However, hydrogel stabilizers remain underutilized in soil engineering, especially those with specialized functionalities.
This study proposes a thermo-responsive hydrogel stabilizer for eco-soil spraying applications in high-slope matrices. A core–shell structured microcarrier (phase-change material shell encapsulating a crosslinker core) was designed and synthesized, leveraging temperature gradients to trigger shell phase transitions and achieve precise temporal control over stabilizer component release. The effects of the stabilizer on the rheological properties and unconfined compressive strength (UCS) of eco-stabilized soil were systematically investigated, with the response mechanisms of the stabilizer thoroughly analyzed.

2. Materials and Methods

2.1. Raw Material

The chemicals used in this study include tetramethylethylenediamine (TMEDA) with a molecular weight of 116.21 and purity ≥ 99.0%, ammonium persulfate (APS) prepared as a 40 wt% solution, polyvinyl alcohol (PVA, Type 1795) with an alcoholysis degree of 92~94%, acrylamide (AAm) with a purity ≥99.0%, and N,N’-methylenebisacrylamide (BiS) with a purity ≥99.0%, all of analytical grade.
Porous ceramsite with a particle size of 6~10 mm and an average pore diameter of 200 μm was obtained from Anhui Mozzi Environmental Technology Co., Ltd., Huainan, China. Tap water (pH 7.0~8.2) was used for testing. The soil matrix was commercial garden soil from Huai’an, Jiangsu Province, processed through crushing, drying, and sieving to obtain silt loess with uniform particle size.

2.2. Sample Preparation

2.2.1. Preparation of Thermoresponsive Hydrogel Stabilizer

The thermo-responsive hydrogel curing agent consists of two components—a precursor solution and a responsive carrier—with a mass ratio of 6.4:1, where the hydrogel curing system containing the thermal response carrier in this study was designated as HSZ. For comparative analysis, a conventional hydrogel curing agent composed of a precursor solution and crosslinking agent, labeled as NSZ, is also employed in this research.
The precursor solution was prepared as follows: 100 g deionized water was measured, and 0.44 g PVA powder was dissolved in it through 95 °C water bath heating with magnetic stirring for 30 min to obtain a PVA aqueous solution; after cooling, 5.89 g AAm, 0.066 g BIS, and 0.21 g TMEDA were added into the PVA solution, followed by mechanical mixing to yield precursor solution A.
The preparation of thermal-responsive carriers involves two steps: (1) Fabrication of A-porous ceramic particles: porous ceramic particles were immersed in a 30 wt.% APS solution and subjected to vacuum treatment for 12 h under negative-pressure conditions (<20 kPa) to ensure complete APS solution infiltration, followed by vacuum drying for 4 h to obtain A-porous ceramic particles. The selection of porous ceramsite as the core of the capsule is mainly due to its load capacity for the solution. (2) Encapsulation of A-porous ceramic particles: First, the paraffin was placed in a constant temperature water bath at 75 °C for continuous heating until it was completely melted. Activated carbon powder with a mass fraction of 3% was uniformly mixed with molten paraffin and fully stirred. Then, the porous ceramsite immersed in ammonium persulfate solution was added to the molten paraffin containing activated carbon, and the paraffin was rolled quickly to cover the surface evenly. The paraffin was taken out and put into cold water to cool and solidify, with the preparation process illustrated in Figure 1.
The simulated external thermal stimulation was conducted on the prepared thermal-responsive carrier using water bath heating at 60 °C for 2 min to observe its responsive behavior, with the differences before and after stimulation displayed as shown in Figure 2.
Figure 3 displays the electron microscopy (XDS-10A; Zhangzhou Luosi Optical Co., Ltd., Zhangzhou, China) images of the responsive carrier, in which the interfacial gap between the encapsulation material and the ceramsite carrier is clearly visible from the high-resolution visualization. Ceramsite, as a widely used carrier material, exhibits a distinct porous structure with uniformly distributed honeycomb-like pores throughout its matrix. These pores provide a large specific surface area, enabling its extensive applications in catalysis, adsorption, and related fields. However, the submicron-scale dimensions of its internal micropores typically render them unresolvable under optical microscopy due to resolution limitations. The internal structure of porous ceramsite was described in detail in the study of Qi Z et al. [22].
The images reveal a homogeneous outer wall thickness of the responsive carrier, indicative of a well-controlled encapsulation process and optimal encapsulation quality. This structural uniformity effectively mitigates potential mechanical impacts during transportation, thereby enhancing the stability and durability of the carrier. Furthermore, the homogeneous encapsulation layer serves as a robust barrier to prevent leakage of internal active components, ensuring the functional integrity and operational efficacy of the responsive carrier during service.

2.2.2. Preparation of Ecological Soil

Thermal-responsive eco-soil was prepared by homogeneously mixing the thermal-responsive hydrogel-based curing agent with soil at a mass ratio of 0.37:1 for 15 min. The thermal triggering process of the eco-soil was completed via heat treatment (500 W; 15 min) using an electric resistance heater. In the spreadability tests, four groups of eco-soil were established, differentiated by the curing agent dosage and thermal stimulation conditions, as summarized in Table 1.

2.3. Test Method

2.3.1. Spreadability and Consistency Tests

The flowability of eco-soil was measured using a mini slump cone based on the flow spread methodology. Samples prepared for 30 min were poured into a small truncated conical mold (height: 60 mm; top diameter: 36 mm; bottom diameter: 60 mm) and smoothed. After slowly lifting the cone on a horizontal surface, the diameter of the eco-soil spread in the vertical direction was measured once flow ceased, with the average diameter recorded as the flow spread. The consistency of eco-soil was evaluated with a Vicat apparatus (TSK-1; Shaoxing Shangyu Prospecting Instrument Factory, Shaoxing, China). Freshly prepared samples were poured into a truncated conical mold (height 40 mm), leveled, and subjected to penetration depth measurements of the consistency needle at specified time intervals. Three eco-soil groups were tested in both flowability and consistency experiments: a control group, an NSZ-modified eco-soil group, and an HSZ-modified eco-soil group.

2.3.2. Mechanical Performance Testing

Following industry standard JTG E51-2009 [24], eco-soil specimens were cured under standard conditions for varying ages. The unconfined compressive strength (UCS) of specimens was evaluated using a universal testing machine (ZQ-990A; Dongwan Zhiqu Precision Instrument Co., Ltd., Dongguan, China) to assess the impact of the novel soil curing agent GHJ-2 on mechanical properties. To eliminate interference from hydrogel swelling caused by moisture variations, all specimens were uniformly pre-dried with hot air at 50 °C for 12 h prior to testing.

2.3.3. pH Value Testing

Surface soil samples were collected, sieved to remove stones and plant residues, air-dried in darkness, and ground through a 2 mm nylon sieve. A 10.0 g aliquot of processed soil was placed in a 50 mL tube, mixed with 25 mL of CO2-free distilled water (soil-to-water ratio 1:2.5), vigorously shaken, and settled for 30 min. The pH meter was preheated for 15 min, sequentially calibrated with pH 4.0 and 7.0 buffer solutions, and validated with pH 7.00 buffer to confirm drift stability. Supernatant was transferred to a beaker, and pH was recorded under low-speed magnetic stirring until stabilization. Triplicate measurements were conducted, with the electrode stored in 3 mol/L KCl solution post-test.

2.3.4. Vegetative Performance

An ecological chamber with a cross-sectional with dimensions 120 mm × 120 mm was established to simulate real-world conditions for evaluating the vegetative performance of eco-soil. A 40 mm-high soil layer containing 2% hydrogel active ingredients was placed at the bottom of the incubator, over which grass seeds and nutrient soil (height: 20 mm) were evenly distributed. The grass species used are tall fescue and alfalfa. The reason for using these two plants is that they are commonly used in slope ecological soils, and their growth forms are easy to measure. The average leaf and root lengths were monitored over time to assess the eco-soil’s suitability for vegetation growth. Measurements were conducted as follows: at seedling emergence and predefined growth stages, plant height was measured using a ruler from the soil surface to the base of the uppermost unfolded leaf sheath, with an accuracy of 1 mm. A five-point sampling method was employed: (1) identifying the diagonal intersection as the central sampling point; (2) selecting four equidistant points along the diagonals; (3) averaging data from all five points to represent the plant height under specific conditions. This protocol evaluated vegetation growth rates in eco-soil layers under outdoor exposure.

2.3.5. Responsive Carrier Release Mechanism

The release performance of carriers in solution was analyzed by real-time monitoring of electrical conductivity changes. Instrument setup: a conductivity meter electrode was immersed in the mixed solution under a constant-temperature water bath (25 °C). Data collection: conductivity values were recorded every 10 min until stabilization (approximately 1–2 h). At 60 min, the solution was subjected to thermal triggering (70 °C; 15 min) using the water bath to activate the thermal-responsive mechanism.
The effect of responsive carriers on the viscosity of the hydrogel system was determined using an NDJ-5Spro digital rotary viscometer, Shanghai Lichen Instrument Technology Co., Ltd., Shanghai, China, with hydrogel active ingredients at a 1% dosage. Rotor No. 1 was selected, and the rotational speed was set to 60.0 RPM, while the temperature of the test liquid was maintained at 25 °C using a constant-temperature water bath. Upon reaching 60 min of measurement, the test liquid underwent thermal triggering (70 °C for 15 min) via the water bath to activate the thermal-responsive mechanism.
The packaged carrier with APS and the unpackaged carrier with APS were tested, with a blank solution as a reference, which were labelled as the ZT-package, ZT-unpackage, and blank group.

3. Results and Discussion

3.1. Rheological Properties of Eco-Soil

Figure 4 shows the spreadability test results for different eco-soil groups. As illustrated in Figure 4, the blank group exhibited a spreadability of 121 mm, while the encapsulated + thermal-responsive group showed a significantly lower value of 74 mm. After thermal stimulation, the blank group’s flow spread decreased slightly from an initial 121 mm to 93 mm, attributed to free water evaporation and accelerated curing reactions under heating. The encapsulated group with 5% responsive carriers (without heating) displayed a spreadability of 121 mm, comparable to the blank group, confirming that encapsulation effectively delayed contact between hydrogel precursors and crosslinkers, maintaining normal rheological properties before stimulation. However, when thermally triggered, spreadability of the encapsulated group sharply dropped from 121 mm to 74 mm, indicating selective rupture of carrier walls under heat, which released crosslinkers to rapidly polymerize with hydrogel precursors, enhancing cohesion. These results demonstrate that the flowability variation in responsive carrier-containing eco-soil originates from controlled release mechanisms rather than thermal effects alone.
Figure 5 illustrates the time-dependent consistency curves of eco-soil containing thermo-responsive curing agents (HSZ) and conventional curing agents (NSZ). During testing, a 15 min thermal trigger was applied at the 60 min mark. As shown in Figure 5, prior to thermal triggering (0–60 min), both the HSZ-modified eco-soil and the blank group maintained stable needle penetration values within a 13 mm range, with comparable consistency change rates that were lower than those of the NSZ-modified eco-soil. This phenomenon confirms that the encapsulation technology of responsive carriers in HSZ effectively isolates the hydrogel crosslinking components from soil interactions, preserving the workability of the eco-soil. In contrast, the NSZ-modified eco-soil exhibited a rapid decline in needle penetration, indicating accelerated thickening. This is attributed to the unrestricted migration of active substances in NSZ, which initiated immediate component reactions post-mixing, leading to pronounced early-stage consolidation trends. Upon activation of the thermal trigger, the responsive carriers in HSZ rapidly ruptured their coatings under thermal stimulation, releasing crosslinking agents and triggering rapid polymerization of hydrogel components. Consequently, the penetration depth sharply decreased to below 20 mm within 30 min.

3.2. Mechanical Performance of Eco-Soil

The influence of hydrogel soil curing agent dosage on the unconfined compressive strength (UCS) of eco-soil was investigated across different curing ages, with results shown in Figure 6. The horizontal axis in the figure represents the mass ratio of the active ingredients in the hydrogel to the ecological soil. As depicted in Figure 6, under constant moisture content (40 wt.%) and identical curing conditions, the dosage of active ingredients exhibited a significantly positive correlation with the UCS of eco-soil. When the active ingredients increased from 0% to 2.0%, the 7 d UCS of eco-soil surged from 0.13 MPa to 1.55 MPa, representing a 1092% enhancement. According to the CJJ/T 286-2018 standard [25], this meets the 7 d strength requirement for Grade III stabilized soil.
Further analysis reveals that the hydrogel curing agent system exhibits unique time-dependent properties. At the optimal dosage of 2.0%, the 28 d strength reached 1.62 MPa, representing only a 4.52% increase over the 7 d baseline value. This enhancement is significantly lower than that of traditional Portland-based curing agents (conventional improvement > 30%). The limited late-stage strength gain may be attributed to the primary efficacy of the hydrogel curing agent occurring during the early curing phase, particularly within the first 48 h. Based on strength development trends, over 90% of the crosslinking reactions in the hydrogel system are completed within 7 d. Its rapid three-dimensional network formation mechanism effectively mitigates the risk of shrinkage-induced cracking observed in traditional materials during later stages. In practical applications, this property accelerates project timelines, reduces labor costs, and enhances quality controllability. Specifically, in scenarios such as ecological slope protection—where both mechanical performance and vegetation growth must be balanced—the controllable strength development curve can precisely align with plant root growth rates, avoiding the ecological isolation effect caused by conventional high-strength stabilized soils. Considering the need for stabilized soils to accommodate root proliferation, hydrogel soil curing agents prioritize ecological compatibility over mechanical performance metrics compared to traditional agents. Consequently, lower dosages may be selected while still meeting project requirements.
Figure 7 illustrates the influence of heating duration on the unconfined compressive strength (UCS) of eco-soil containing hydrogel curing agents, with an active ingredients dosage of 2.0 wt.%. As shown in Figure 7, the UCS of eco-soil increased with prolonged heating time. When the heating duration rose from 0 h to 2 h, the 7 d UCS of encapsulated specimens surged from an initial value of 0.13 MPa to 1.23 MPa, achieving 79% of the unencapsulated control group’s strength (1.55 MPa), with a strength loss rate confined within 21%. This demonstrates that external thermal stimulation positively regulates stabilized soil specimens, confirming the feasibility of precisely releasing hydrogel initiators via temperature modulation. Notably, extending heating time to 3 h resulted in a marginal strength increase to 1.25 MPa, showing reduced efficacy compared to the 2 h treatment. Considering energy efficiency ratios and material stability, optimal thermal input power must be selected. This ensures that the thermo-responsive eco-soil system maintains high strength conversion efficiency while avoiding matrix damage caused by excessive heat exposure.

3.3. Vegetative Performance of Eco-Soil

Figure 8 illustrates the effect of hydrogel active ingredients’ dosage on the pH of eco-soil. As shown in Figure 8, soil treated with the hydrogel system maintained pH values within 6.5–8.0, distinct from the high alkalinity of traditional Portland cement-based materials. At the optimal 2.0% dosage, pH values for 7 d, 14 d, and 28 d specimens were 7.3 ± 0.1, 7.5 ± 0.1, and 7.6 ± 0.2, respectively, transitioning from weakly alkaline to neutral—consistent with the vegetation-friendly pH range (5.5–8.5) specified in GB/T 51435-2021 [26]. The hydrogel’s three-dimensional network binds to soil colloids via hydrogen bonds, while carboxyl groups in the acrylic acid–acrylamide copolymer backbone buffer OH concentrations, lowering pH compared to cement-based systems.
Figure 9 displays the growth dynamics of different vegetation combinations in eco-soil containing hydrogel curing agents. Adding HSZ resulted in the vegetation length being approximately 15% shorter compared to when HSZ was not added. However, it showed good growth over time and reached sufficient length for the landscape. As shown, both tall fescue and alfalfa achieved an average leaf length exceeding 8 cm after 10 d of seeding, indicating no inhibitory effect of the hydrogel matrix on early-stage germination. With the curing time extended to 60 d, the vegetation exhibited significant development: the average leaf length of tall fescue reached 200 ± 5 mm, accompanied by dense fibrous root branching structures. Figure 10 presents a time-dependent visualization of tall fescue growth in the eco-soil. By 30 d, lush foliage had fully developed in the tall fescue group. Continuous monitoring until 90 d revealed no wilting or lodging across all vegetation groups, with roots visibly penetrating the eco-soil layer. These results demonstrate that the hydrogel–vegetation composite system, through bionic structural design, achieves synergistic enhancement of soil mechanical performance and ecological functionality. This provides an innovative solution for eco-friendly construction in applications such as slope restoration.

3.4. Responsive Carrier Release Mechanism

Figure 11 illustrates the release behavior of responsive carriers in aqueous solutions. Three sets of conductivity measurements were conducted: with the blank solution, with the solution with encapsulated carriers, and with the solution with non-encapsulated carriers (NSZ group), using 70 °C heating for 15 min to activate the response. As shown in the figure, prior to thermal stimulation (0~15 min), the conductivity of both the encapsulated and blank groups remained stable within 20~30 μS/cm, indicating that the encapsulation coating effectively restricted ion migration at ambient temperature, maintaining electrochemical inertness. In contrast, the NSZ group was directly exposed to the solution because the carrier loaded with APS was not encapsulated, and its initial conductivity was higher and reached 150 μS/cm. Upon thermal triggering, the encapsulation coating underwent phase transition and dissociation, enabling directional carrier release. The conductivity of the encapsulated group surged to 120 μS/cm within 5 min, approaching the dynamic equilibrium level of the NSZ group (140 μS/cm). This abrupt transition confirms the feasibility of thermally responsive encapsulation technology in precisely regulating carrier release kinetics.
Figure 12 demonstrates the release behavior of responsive carriers in a hydrogel system. Specimens were thermally triggered using a 500 W power source for 15 min. As shown in the figure, prior to thermal activation (0–60 min), the viscosity of both the encapsulated (ZT-package) and blank groups remained stable within 0–5 mPa·s, exhibiting rheological properties similar to conventional curing slurries. This confirms that the encapsulation coating technology effectively delays contact between active hydrogel components and crosslinkers through physical isolation, ensuring normal fluidity during storage and construction. In contrast, the ZT-unpackage group (with unencapsulated carriers) showed immediate crosslinker release upon mixing, triggering rapid reactions with precursor solutions. This resulted in an initial viscosity exceeding 35 mPa·s, indicating significant pre-crosslinking tendencies. Upon thermal triggering (60 min), the ZT-package group exhibited rapid dissociation of the encapsulation layer under heat, followed by directional release of active components. This initiated crosslinking reactions, driving viscosity to surge beyond 30 mPa·s within 30 min—demonstrating pronounced thermo-responsive behavior.

4. Conclusions

This study proposes a thermo-responsive hydrogel-based ecological soil to resolve the trade-off between fluidity and cohesion in high-slope construction. The key findings are summarized as follows:
(1) A kind of thermo-responsive hydrogel stabilizer (HSZ) for ecological soil was designed and prepared.
(2) After the addition of HSZ, the 7 d unconfined compressive strength of ecological soil reaches 1.55 MPa. The PH of ecological soil was maintained between 6.5 and 8.0. At 10 d, tall fescue and alfalfa leaves were longer than 8 cm, and at 30 d, the leaf density of tall fescue had greatly risen. The strength development matched root growth, which not only ensures plant growth but also improves slope protection performance.
(3) Upon thermal activation, HSZ-modified eco-soil exhibited significant rheological changes (reduced spreadability; increased consistency). Optimal thermal stimulation achieved 79% strength conversion efficiency.
(4) Conductivity and viscosity analyses confirmed precise thermo-responsive carrier release in both aqueous and hydrogel systems.
This thermo-responsive hydrogel system enables dynamic rheological regulation, showing promise for high-slope spray applications requiring tunable fluidity-to-strength transitions.

Author Contributions

Conceptualization, X.Z. and W.Z.; methodology, P.Y.; software, Z.L.; formal analysis, P.Y. and Z.L.; investigation, W.Z.; resources, X.Z.; data curation, P.Y.; writing—original draft preparation, J.Z. and Y.G.; writing—review and editing, X.Z. and W.Z.; visualization, J.Z. and H.C.; supervision, Y.G. and H.C.; funding acquisition, Y.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research was supported by the Three Gorges Jinsha River Chuanyun Hydropower Development Co., Ltd. Yibin Xiangjiaba Power Plant (No. Z422302058).

Data Availability Statement

Data will be made available on request.

Conflicts of Interest

Author Xiaoyan Zhou, Weihao Zhang, Peng Yuanm, and Zhao Liu are employed by the China Yangtze Power Co., Ltd. The remaining authors declare that this research was conducted in the absence of any commercial or financial relationships that could be construed as potential conflicts of interest. The authors declare that this study received funding from Three Gorges Jinsha River Chuanyun Hydropower Development Co., Ltd. Yibin Xiangjiaba Power Plant. The funder was not involved in the study design; in the collection, analysis, or interpretation of data; in the writing of this article; or in the decision to submit it for publication.

References

  1. Li, Y.; Li, T. Stability Mechanism and Research Progress of Soil Stabilizer. Mater. Rep. 2020, 34, 273–277. [Google Scholar]
  2. Fan, H.; Gao, J.; Wu, P. Prospect of researches on soil stabilizer. J. Northwest A F Univ. (Nat. Sci. Ed.) 2006, 34, 141–146+152. [Google Scholar]
  3. Ou, O.; Zhang, X.G.; Yi, N.P. The Experimental Study on Strength of Subgrade Soil Treated with Liquid Stabilizer. Adv. Eng. Msterials 2011, 194–196, 985–988. [Google Scholar] [CrossRef]
  4. Li, Q.; Sun, K.W.; Xu, B.; Li, S.P. Progress and Application on Curing Mechanism of Soil Stabilizer. Mater. Rev. 2011, 25, 64–67. [Google Scholar]
  5. Zhu, Y.; Feng, X.; He, R.; Li, W.; Xue, C. Performance Evaluation and Mechanism Study of Solid-waste SoilStabilizer. Appl. Chem. Ind. 2025, 54, 605. [Google Scholar]
  6. Zhong, Y.; Zhang, X.; Yuan, R.; Wu, X.; Chen, L. Research Progress in the Stabilization Mechanism of Non-calcium-based Soil Stabilizer and Its Application Performance. Mater. Rev. 2022, 36, 9. [Google Scholar]
  7. Gao, Y.; Xu, Y.; Che, H. Situation and existing problems of vegetation restoration technology of hard rock slope in open-pit mining area. China Min. Mag. 2019, 28, 60–65. [Google Scholar]
  8. Yang, L.; Tian, J.; Yang, Y.; Sun, L. State-of-art of Research on Liquid Accelerators for Shotcrete. Tunn. Constr. 2017, 37, 543–552. [Google Scholar]
  9. Ma, Z.; Wang, L.; Ma, J. Development of shotcrete technologies and accelerators. Concrete 2011, 12, 126–128. [Google Scholar]
  10. Zhang, T.; Xu, Y.Y.; Wang, H. Application and Curing Mechanism of Soil Stabilizer. Adv. Mater. Process. 2012, 557–559, 809–812. [Google Scholar] [CrossRef]
  11. Su, M.; Wang, Z.; Zhao, P. The Application and Development Status of Sprayed Concrete and Flash Setting Accelerating Admixtures. China Concr. 2022, 2, 34–40. [Google Scholar]
  12. Peng, S.; P.E., J.D.R.; ASCE, M.; Zhang, W.; Luo, G.; Cao, H.; Pan, H. Laboratory Investigation of the Effects of Blanket Defect Size on Initiation of Backward Erosion Piping. Engineering 2024, 150, 4024095. [Google Scholar] [CrossRef]
  13. Su, Y.; Cui, Y.-J.; Dupla, J.-C.; Canou, J. Soil-water retention behaviour of fine/coarse soil mixture with varying coarse grain contents and fine soil dry densities. Can. Geotech. J. 2022, 59, 291–299. [Google Scholar] [CrossRef]
  14. Lin, J.; Cheng, Q.; Kumar, A.; Zhang, W.; Yu, Z.; Hui, D.; Zhang, C.; Shan, S. Effect of degradable microplastics, biochar and their coexistence on soil organic matter decomposition: A critical review. TrAC Trends Anal. Chem. 2024, 183, 118082. [Google Scholar] [CrossRef]
  15. Gong, H.; Yin, Y.; Chen, Z.; Zhang, Q.; Tian, X.; Wang, Z.; Wang, Y.; Cui, Z. A dynamic optimization of soil phosphorus status approach could reduce phosphorus fertilizer use by half in China. Nat. Commun. 2025, 16, 976. [Google Scholar] [CrossRef] [PubMed]
  16. Lu, X.; Xiang, W.; Fan, W.; Yu, H. Research on the Experimental Effect and Mechanism of Ionic Soil Stabilizer ReinforcingWuhan Red Clay. China Univ. Geosci. 2010, 32, 127–129. [Google Scholar]
  17. Zhang, G.; Niu, J.; Sun, J.; Li, H. Soil Stabilizer and Its Application in Soil and Water Conservation: A Review. Soils 2018, 50, 28–34. [Google Scholar]
  18. Zhou, H.; Shen, X. Application Research Situation and Prospect of Soil Stabilizer. Mater. Rep. 2014, 28, 134–138. [Google Scholar]
  19. Sun, Q.; Xu, Y.; Zhang, F. The present research and foreground expectation of soil stabilizer. J. Heilongjiang Inst. Technol. 2005, 19, 1–4. [Google Scholar]
  20. He, P.; Xiao, W.; Huang, H.; Zhang, Q. Synthesis and water absorbency of high water absorbing poly(sodium acrylate acrylamide-2-hydroxyethyl methacrylate). Polym. Mater. Sci. Eng. 1999, 11, 65–68. [Google Scholar]
  21. Guo, M.; Li, G.; Cai, M.; Hou, X.; Huang, K.; Tang, J.; Guo, C.F. A Tough Hydrogel Adhesive for the Repair of Archaeological Pottery. Nano Lett. 2023, 23, 1371–1378. [Google Scholar] [CrossRef] [PubMed]
  22. Zhang, Q.; Feng, P.; Shi, J.; Wang, H. Controlled release of corrosion inhibitor from microwave-responsive capsules and anti-corrosion performance of steel bars. Corros. Sci. 2022, 207, 110572. [Google Scholar] [CrossRef]
  23. Zhao, Z.; Shan, Y.; Wang, H.; Lu, H.; Liu, X.; Wang, B.; Song, X. Sustainable Cement-Free Soil Stabilization via a Mussel Mimicry, Water-Resistant Hydrogel. Chem. Mater. 2022, 34, 10443–10450. [Google Scholar] [CrossRef]
  24. JTG E51-2009; Test Methods of Materials Stabilized with Inorganic Binders for Highway Engineering. Ministry of Transport of the People’s Republic of China: Beijing, China, 2009.
  25. CJJ/T 286-2018; Technical Standard for Application of Soil Stabilizer. Ministry of Housing and Urban-Rural Development of the People’s Republic of China: Beijing, China, 2018.
  26. GB/T 51435-2021; Technical Standard for Rural Solid Waste Collection Transportation and Treatment. Ministry of Housing and Urban-Rural Development of the People’s Republic of China: Beijing, China, 2021.
Figure 1. Preparation process of thermal-responsive carriers.
Figure 1. Preparation process of thermal-responsive carriers.
Applsci 15 08279 g001
Figure 2. Thermal-responsive carrier samples: (a) before stimulation; (b) after stimulation. These illustrate the decrease of capsule shell coverage before and after thermal stimulation.
Figure 2. Thermal-responsive carrier samples: (a) before stimulation; (b) after stimulation. These illustrate the decrease of capsule shell coverage before and after thermal stimulation.
Applsci 15 08279 g002
Figure 3. Response carrier EM image.
Figure 3. Response carrier EM image.
Applsci 15 08279 g003
Figure 4. Spreadability of eco-soil.
Figure 4. Spreadability of eco-soil.
Applsci 15 08279 g004
Figure 5. Time-dependent consistency curves of eco-soil.
Figure 5. Time-dependent consistency curves of eco-soil.
Applsci 15 08279 g005
Figure 6. Effect of active ingredients in hydrogel on UCS of eco-soil.
Figure 6. Effect of active ingredients in hydrogel on UCS of eco-soil.
Applsci 15 08279 g006
Figure 7. Effect of heating duration on UCS of eco-soil.
Figure 7. Effect of heating duration on UCS of eco-soil.
Applsci 15 08279 g007
Figure 8. Effect of active ingredients in hydrogel on pH of eco-soil.
Figure 8. Effect of active ingredients in hydrogel on pH of eco-soil.
Applsci 15 08279 g008
Figure 9. Vegetation height evolution in eco-soil over time.
Figure 9. Vegetation height evolution in eco-soil over time.
Applsci 15 08279 g009
Figure 10. Schematic diagram of vegetation growth in eco-soil at different curing ages.
Figure 10. Schematic diagram of vegetation growth in eco-soil at different curing ages.
Applsci 15 08279 g010
Figure 11. Controlled release of responsive carriers in aqueous solution.
Figure 11. Controlled release of responsive carriers in aqueous solution.
Applsci 15 08279 g011
Figure 12. Controlled release of responsive carriers in hydrogel system.
Figure 12. Controlled release of responsive carriers in hydrogel system.
Applsci 15 08279 g012
Table 1. Types of ecological soil.
Table 1. Types of ecological soil.
SymbolSoil Relative MassSoil StabilizerHeat Trigger
Blank group1××
Thermal group1×
Capsules group1×
T-Capsules group1
Note: × means not used; √ means to be used.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Zhou, X.; Zhang, W.; Yuan, P.; Liu, Z.; Zhao, J.; Gu, Y.; Chu, H. Synthesis of Thermo-Responsive Hydrogel Stabilizer and Its Impact on the Performance of Ecological Soil. Appl. Sci. 2025, 15, 8279. https://doi.org/10.3390/app15158279

AMA Style

Zhou X, Zhang W, Yuan P, Liu Z, Zhao J, Gu Y, Chu H. Synthesis of Thermo-Responsive Hydrogel Stabilizer and Its Impact on the Performance of Ecological Soil. Applied Sciences. 2025; 15(15):8279. https://doi.org/10.3390/app15158279

Chicago/Turabian Style

Zhou, Xiaoyan, Weihao Zhang, Peng Yuan, Zhao Liu, Jiaqiang Zhao, Yue Gu, and Hongqiang Chu. 2025. "Synthesis of Thermo-Responsive Hydrogel Stabilizer and Its Impact on the Performance of Ecological Soil" Applied Sciences 15, no. 15: 8279. https://doi.org/10.3390/app15158279

APA Style

Zhou, X., Zhang, W., Yuan, P., Liu, Z., Zhao, J., Gu, Y., & Chu, H. (2025). Synthesis of Thermo-Responsive Hydrogel Stabilizer and Its Impact on the Performance of Ecological Soil. Applied Sciences, 15(15), 8279. https://doi.org/10.3390/app15158279

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop