Development and Performance Study of a Slow-Releasing Anti-Icing Fog Seal Based on Response Surface Methodology

Abstract

To prevent traffic accidents caused by icy roads in winter and damage to roads resulting from repeated freeze–thaw cycles, this paper proposes an optimized design plan for slow-release anti-icing fog seal. The effects of the dosages of slow-release anti-icing agent, water-based epoxy resin modifier, and penetrant on the ice- and snow-melting properties, mechanical properties, and penetration properties of the fog seal were investigated. Based on single-factor experiments, a Box–Behnken model was established, and the response surface method was employed to optimize the design of the fog seal. Subsequently, wear resistance was assessed using an accelerated loading test, while anti-skid performance was evaluated through the British pendulum test and the sand patch test. The results indicate that the optimal ratio for the slow-release anti-icing fog seal is 13% slow-release anti-icing agent, 20% water-based epoxy resin modifier, and 12% penetrant. This material demonstrated excellent ice- and snow-melting performance as well as good wear and skid resistance in testing, providing valuable insights for the application of the slow-release anti-icing agent in new pavement maintenance techniques.

1. Introduction

Road surface conditions are recognized as one of the most critical factors influencing traffic safety. Empirical studies have demonstrated that the friction coefficients of asphalt pavements exhibit significant variations under different meteorological conditions, with values of 0.6, 0.2, and 0.15 under dry, snowy, and icy conditions, respectively. These variations directly impact vehicle traction and braking performance, thereby increasing the risk of accidents [1]. Notably, traffic accidents attributable to snow and ice accumulation constitute approximately 35% of all winter-related traffic incidents. Such accidents not only result in substantial economic losses but also pose significant risks to human life, leading to injuries and fatalities. As a result, the development and implementation of advanced snow-melting and ice removal technologies have become imperative to enhance road safety and ensure uninterrupted traffic flow.

The current snow and ice removal technologies can be broadly categorized into two types: passive and active methods [2,3]. Traditional passive methods, such as manual salt spreading and mechanical snow removal, are often criticized for their inefficiency and potential damage to road surfaces [4,5]. In contrast, active snow and ice removal technologies leverage physical or chemical mechanisms to enable road surfaces to autonomously melt snow and prevent ice formation. These advanced methods have garnered increasing attention from both academic researchers and engineering professionals. Examples of such technologies include rubber self-stressed pavement [6,7], slow-release anti-icing asphalt pavement [7,8,9], self-heating pavement [10,11,12,13], and phase-change material ice and snow melting pavement [14,15]. Among these, slow-release anti-icing asphalt pavement has demonstrated particularly promising results in recent years, owing to its superior anti-icing performance and straightforward construction process.

Anti-icing asphalt pavement partially or completely replaces fine aggregate or mineral filler with materials that lower the freezing point of the pavement [16]. Under the combined influence of vehicular load and micromechanical forces, the active components within the slow-release anti-icing agent gradually migrate to the pavement surface. This process effectively mitigates the accumulation of ice and snow by reducing the freezing point of the pavement surface and weakening the adhesion between the ice layer and the pavement [17,18]. Currently, the predominant method for incorporating slow-release anti-icing agent into pavements involves their substitution for mineral powder or aggregates within the asphalt mixture matrix [19,20]. For instance, in the construction of a 4 cm thick surface layer with a bulk density of approximately 2.43 t/m³, a 4% additive dosage translates to a salt requirement of roughly 5 kg per square meter. This material configuration incurs significant economic costs, with an estimated additional expenditure of 150,000 RMB per kilometer for a single lane. Furthermore, the slow release of anti-icing materials from the lower layers of the asphalt mixture diminishes their effectiveness on the pavement surface, thereby limiting their practical application.

Fog sealer is a pavement maintenance technology based on emulsified asphalt, primarily used to seal the fine voids on the road surface and enhance the moisture damage resistance of the pavement [21,22]. In recent years, researchers have sought to augment the functionality of a fog seal. For example, Duan combined fog seal technology with photocatalytic technology to develop a 3DOM TiO₂ capable of effectively degrading harmful gases in automobile exhaust [23]. Additionally, Sheng et al. integrated a fog seal with self-healing technology by incorporating multi-walled carbon nanotubes and fibers into asphalt to create a self-healing fog seal [24]. Furthermore, a slow-release anti-icing fog seal has emerged, which combines fog seal and anti-icing technology by mixing emulsified asphalt with anti-icing materials to form a low freezing-point asphalt emulsion. This emulsion is sprayed onto the surface layer of the pavement, providing an active snow and ice melting function. Meng et al. designed a low freezing-point fog seal with excellent impermeability, anti-icing properties, and abrasion resistance [25]. Zhu et al. analyzed the mechanism of an anti-icing fog seal using the principles of pharmacokinetics and the Ritger–Peppas equation, verifying their service life through simulation models [26]. Yun et al. investigated anti-icing coatings, demonstrating their effectiveness in inhibiting icing and secondary icing [27]. Lei et al. optimized the material composition of the slow-release anti-icing fog seal through orthogonal tests, concluding that the optimal snow and ice melting effect was achieved with a salt dosage of 14% [28]. Zhu et al. examined the effects of deicer content, temperature, and asphalt mixture surface structure on the release of a deicer based on the principles of drug release kinetics [29].

In this paper, the slow-release anti-icing fog sealer was prepared by a self-developed anti-icing agent with a core–shell structure. The material components of the fog seal were systematically optimized using a multi-objective optimization design system based on response surface methodology (RSM). The optimization process considered the amount of waterborne epoxy resin-modified emulsified asphalt, the amount of penetrant, and the amount of slow-release anti-icing agent as independent variables, with the ice-melting rate, ice–road bonding strength, and penetration depth serving as response indicators. Through this optimization framework, a synergistic enhancement in both the material’s ice-melting performance and its road performance was achieved. Subsequently, the evolution of the fog sealer’s wear resistance was investigated using accelerated loading tests. Additionally, the changes in the anti-skid performance of the fog seal surface were comprehensively evaluated using the British pendulum test and the sand-laying method. The detailed research process is illustrated in Figure 1.

2. Materials and Methods

2.1. Raw Material

2.1.1. Waterborne Epoxy-Modified Emulsified Asphalt

The experimental program employed cationic emulsified asphalt as the matrix material, with its key technical specifications systematically characterized in

Table 1. Basic properties of emulsified asphalt.

Test Items	Quality Indicators	Test Result
Demulsification rate	Quick cracking or medium cracking	Quick cracking
Particle charge	Cationic	Cationic
Residue on sieve (1.18 mm sieve/%)	≥0.1	0.11
Engler viscosity (E2s)	1~6	4.3
Storage stability at room temperature (1 day/%)	≤1	0.6

. For the curing process, a dilutable amine-based curing agent (designated as EC) was selected based on its compatibility with the matrix system; the fundamental performance parameters of EC are comprehensively presented in

Table 2. Basic properties of waterborne epoxy resin.

Test Items	Test Result
Solid content (%)	50
pH value	7~8
Epoxy value (Equivalent/100 g)	0.23
Storage stability (180 days)	No Stratification
Centrifugal stability (3000 r/min, 30 min)	No Stratification

. Furthermore, this study used a self-developed water-based epoxy resin, which showed excellent stability. The relevant data are detailed in

Table 3. Basic properties of the EC curing agent.

Test Items	Test Result
Appearance	Light yellow uniform fluid
Solid content (%)	50 ± 2
ph	7~10
Active hydrogen equivalent (solid content)	210 ± 30
Viscosity (mpa·s/25 °C)	4000–7000
Specific gravity	1.02–1.09

. According to the previous research results of the research group, the best effect can be obtained when the water-based epoxy resin and the curing agent are mixed in a mass ratio of 2:1 [30].

2.1.2. Slow-Release Anti-Icing Agent

In this study, a self-developed slow-release anti-icing agent featuring a core–shell structure was utilized [31], as detailed in

Table 4. Basic properties of slow-release anti-icing material.

Test Items	Unit	Standard Value	Test Result
Appearance	-	-	White powder
Chloride ion content	%	≥40	46.25
Relative density	-	≥1.7	2.276
Salt release amount	%	≤0.4	0.1
Freezing point	°C	≤−5	−10
Ice melting rate	%	≥20	25.6
Moisture content	%	≤1	0.51

[32]. The independently developed core–shell anti-icing agent adjusts the glass transition temperature of the outer shell to make the material elastic above 0 °C and brittle below 0 °C. When the glass transition temperature is reached, the core–shell anti-icing agent breaks under the action of the load and plays the role of melting snow and suppressing ice. To ensure uniformity and effectiveness, the prepared slow-release anti-icing agent was sieved to select particles with a size of less than 0.075 mm. This treatment method optimizes the distribution of the material and enhances its performance on the road surface, thereby improving its snow and ice melting effects.

2.2. Slow-Release Anti-Icing Fog Seal Material Preparation

2.2.1. Preparation Process

The slow-release anti-icing fog seal was manufactured as follows. Firstly, the slow-release anti-icing agent was sieved to separate tiny particles with diameters of less than 0.075 mm. A water-based epoxy resin modifier was then created by physically combining the water-based epoxy resin and the curing agent at a ratio of 2:1. Subsequently, the waterborne epoxy resin-modified emulsified asphalt was created by fully blending the conventional emulsified asphalt and the synthesized waterborne epoxy resin modifier at an ambient temperature of 25 ± 1 °C and a stirring speed of 200 rpm. Finally, a precise amount of penetrant and sustained-release anti-icing material was mixed into the water-based epoxy-modified emulsified asphalt and swirled at 100 rpm for 3 min at room temperature to create the final sustained-release anti-icing fog seal [33].

2.2.2. Single-Factor Determination of Component Range

(1)

The dosage of slow-release anti-icing material:

Emulsified asphalt (100 g), water-based epoxy resin (15 g), and penetrant (12 g) were used to explore the effect of the dosage of slow-release anti-icing material (0%, 5%, 10%, 15%, and 20%) on the anti-icing fog seal.

(2)

The dosage of water-based epoxy resin modifier:

Emulsified asphalt (100 g), penetrant (12 g), and slow-release anti-icing material (10 g) were used to explore the effect of the dosage of water-based epoxy resin modifier (0%, 5%, 10%, 15%, 20%, and 25%) on the anti-icing fog seal.

(3)

Penetrant dosage:

Emulsified asphalt (100 g), water-based epoxy resin (15 g), and anti-icing agent (10 g) were used to explore the effect of penetrant dosage (0%, 4%, 8%, 12%, 16%, and 20%) on the anti-icing fog seal.

2.2.3. Response Surface Experiment

At present, there are many mathematical analysis methods to obtain the optimal solution of an experimental formula [34]. Building upon the single-factor experiments, the formulation of the sustained-release anti-icing fog seal was systematically optimized using response surface methodology (RSM). The Box–Behnken design model was systematically constructed with the aid of the Design Expert version 10 software. These factors included the dosage of the sustained-release anti-icing agent, the application rate of the waterborne epoxy resin modifier, and the amount of penetrant. To quantitatively evaluate the influence of these variables, three critical performance indicators were selected: ice-melting efficiency (Y₁), ice–pavement adhesion strength (Y₂), and permeability (Y₃).

2.2.4. Ice-Melting Performance Test

In this test, the prepared slow-release anti-icing fog seal material was evenly applied to the interior of a 9 cm diameter Petri dish, with 2 g of the material per dish. The Petri dishes were then left to stand at room temperature for 24 h with ventilation to ensure the complete curing of the material. Following this, 25 g of ultrapure water was added to each Petri dish, and they were placed in a refrigerator set at −5 °C to freeze for 24 h. After the freezing process was complete, the Petri dishes were removed, and the amount of melted ice after 40 min was recorded to evaluate the ice-melting performance of the slow-release anti-icing fog seal material.

2.2.5. Ice–Road Surface Adhesion Strength Test

In this study, the ice–road adhesion strength was employed as a critical performance indicator for assessing the ice-melting efficacy of the slow-release anti-icing fog seal materials [35,36], as depicted in Figure 2. The experimental procedure is outlined in detail as follows: Initially, the slow-release anti-icing fog seal materials were uniformly applied across the surface of a rutting board. Subsequently, a layer of non-woven fabric was adhered to the mold’s surface, which was then positioned on the specimen’s surface, followed by applying 50 mL of deionized water to saturate the non-woven fabric and the specimen’s surface completely. The specimen was placed in a low-temperature chamber set at −10 °C for 5 h to induce the formation of a dense ice layer on the specimen’s surface. The ice–road adhesion strength on the specimen’s surface was subsequently evaluated using a universal testing machine. To ensure the accuracy of the experimental results, each group of specimens was tested three times, and the average value was taken to reduce the experimental error.

2.2.6. Permeability Test

This test, proposed by Meng from the Harbin Institute of Technology, is designed to evaluate the permeability of the slow-release anti-icing fog seal material [25], as shown in Figure 3. The test evaluates the permeability of the material by measuring the penetration depth of emulsified asphalt in standard sand in a measuring cylinder. The test measures the penetration depth to assess the material’s permeability. A higher permeability coefficient indicates a stronger ability of the fog seal to penetrate. The calculation method is as follows:

$$S_a={\displaystyle \frac{k\times (65-m_a)}{A}}$$

(1)

where S_a represents the depth of penetration (cm); m_a represents the mass of unpenetrated sand (g); k represents the bulk density of standard sand (usually 0.715 g/cm³); and A represents the bottom area of the cylinder (cm², usually 4.15 cm²).

2.3. The Performance Evaluation of Slow-Release Anti-Icing Fog Seal

The slow-release anti-ice fog seal specimen was prepared by the manual brushing method, and the brushing amount was 0.75 kg/m². First, the slow-release anti-ice fog seal material was evenly applied on the surface of the rutting plate specimen; then, the wear-resistant particles were evenly spread using a standard sieve, and the specimen was placed in an oven at 60 °C for drying. The structural schematic diagram is shown in Figure 4. Three different types of wear-resistant particles, limestone, basalt, and quartz sand, were used in this study. The technical properties of the selected wear-resistant particles are shown in

Table 5. The technical properties of the abrasion-resistant particles.

Type	Component	Acidity or Alkalinity	Density (g/cm3)	Mohs Hardness
Quartz sand	SiO2 (≥90%)	Acidic	2.65	7
Limestone	CaCO3	Alkaline	2.70	3
Basalt	SiO2 (≤50%), Al2O3, CaO, etc.	Alkaline	2.83	6

.

2.3.1. Abrasion Resistance Test

Since the fog seal serves as a pavement maintenance layer that is in direct contact with vehicle tires, its abrasion resistance is critically important. In this study, a small-scale accelerated loading test was conducted to evaluate the abrasion resistance of the slow-release anti-icing fog seal. Previous studies have demonstrated that abrasion resistance is closely related to the type of abrasion-resistant particles used [37]. Cumulative mass loss was employed as the evaluation index to experimentally assess the abrasion resistance of the fog seal under varying loading conditions, thereby ensuring its effectiveness and reliability in practical applications, as illustrated in Figure 5.

2.3.2. Skid Resistance Test

To evaluate the anti-skid performance of the slow-release anti-icing fog seal, this study employed two methods: the British pendulum test and the sand patch test, according to the JTG 3450 [38]. The British pendulum test was utilized to measure the road surface’s pendulum value before and after abrasion, thereby assessing the surface’s friction performance, as shown in Figure 6a. Subsequently, the sand patch test was employed to determine the texture depth of the road surface, as illustrated in Figure 6b, quantifying the macro-texture characteristics. The anti-skid performance of the slow-release anti-icing fog seal was characterized by comparing the changes in the pendulum value and texture depth.

3. Results and Analysis

3.1. Analysis of Single-Factor Experimental Results

3.1.1. The Effect of Slow-Release Anti-Icing Agent

The effects of the dosage of the slow-release anti-icing agent on the ice-melting performance and permeability were investigated using the methods outlined in Section 2.2.4 and Section 2.2.6. The results are illustrated in Figure 7. As the concentration of the anti-icing agent increases, a notable enhancement in the ice-melting effect of the fog seal was observed. Conversely, the permeability exhibits an inverse relationship with the concentration of the anti-icing agent. This can be explained by the viscosity enhancement and fluidity reduction in the fog seal following anti-icing agent incorporation, which consequently leads to decreased permeability. The intersection point observed at a 12% dosage, where the ice-melting capacity and permeability curves converge, represents a critical optimization point. This specific concentration provides an optimal balance between these two crucial performance parameters. Through the comprehensive analysis of experimental data, it is recommended to maintain the sustained-release anti-icing agent dosage within the range from 10% to 15%. This dosage range not only ensures enhanced ice-melting properties but also preserves adequate permeability, thereby achieving an optimal overall performance of the material.

3.1.2. The Effect of Waterborne Epoxy Resin Modifier

According to the method described in Section 2.2.5, the ice–road surface adhesion strength of the waterborne epoxy resin modifier was tested at varying dosages (0%, 5%, 10%, 15%, 20%, and 25%), with the results presented in Figure 8. As illustrated in Figure 8, the addition of a waterborne epoxy resin modifier significantly enhances the bond strength between ice and roads. Within the modifier dosage range from 10% to 20%, the bond strength increased markedly from 0.124 KN to 0.303 KN, corresponding to an increase of 144%. This substantial improvement indicates that the concentration range from 10% to 20% was optimal for achieving the most pronounced modification effect. However, when the modifier dosage exceeds 20%, the rate of increased bond strength diminishes significantly. Specifically, in the range from 20% to 30%, the bond strength only increases by 15.5%. This suggests that the marginal benefit of increasing the modifier dosage beyond 20% was relatively limited. This can be attributed to the incorporation of epoxy resin, which reduces the dissolution pathways of the sustained-release anti-icing material, thereby lowering its precipitation rate. The interfacial bonding strength between ice and the fog seal gradually increases with the decrease in the dissolved salt concentration. Upon reaching the threshold concentration of the waterborne epoxy resin, the dissolution rate of the salt-storage material stabilizes. Given that the increase in adhesion strength plateaus beyond 20%, and to improve material cost-efficiency, the dosage of the waterborne epoxy resin modifier in the subsequent optimization of the slow-release anti-icing fog seal formulation using the response surface method was controlled between 10% and 20%.

3.1.3. The Effect of Permeating Agent

For the optimization experimental design, the effect of varying permeating agent dosages (0%, 4%, 8%, 12%, 16%, and 20%) on the penetration depth was evaluated while maintaining the slow-release anti-icing material dosage at 10% and the water-based epoxy resin modifier dosage at 15%. The results are illustrated in Figure 9. When the permeating agent dosage was below 12%, the penetration depth increased significantly with higher penetrant concentrations. The maximum penetration depth of 8.96 mm was achieved at 12% permeating agent concentration. However, beyond this threshold, a gradual decrease in penetration depth was noted, indicating that excessive permeating agent concentrations may adversely affect the permeability characteristics. The phenomenon was primarily due to the penetrant-induced reduction in the surface energy of the fog seal material, which lowered the interfacial adhesion resistance and promoted deeper penetration. However, as the penetrant concentration further increased, its compatibility with the emulsified asphalt system declined. This incompatibility resulted in a rise in internal resistance and a subsequent increase in the viscosity of the fog seal. Consequently, the ability of the fog seal was no longer enhanced and gradually deteriorated [39]. Therefore, to achieve optimal permeability and ensure efficient material use, it is recommended that the permeating agent dosage be controlled between 9% and 15% during the subsequent optimization of the slow-release anti-icing fog seal formulation using the response surface method.

3.2. Response Surface Method Analysis

3.2.1. Response Surface Model Fitting Analysis

Through single-factor experimental analysis, the optimal dosage ranges were determined as follows: 10% to 15% for the slow-release anti-icing agent, 10% to 20% for the water-based epoxy emulsified asphalt, and 9% to 15% for the penetrant. Based on these ranges, response surface methodology (RSM) was employed to systematically investigate the effects of each factor on the response variables.

Table 6. Experimental design table.

Variable Factors	Number	Level (%)
		1	2	3
Slow-release anti-icing agent	X1	10	12.5	15
Waterborne epoxy resin modifier	X2	10	15	20
Permeating agent	X3	9	12	15

summarizes the experimental factors and their corresponding levels. The experimental design and results are presented in detail in

Table 7. Test results.

Number	X1/%	X2/%	X3/%	Y1/g	Y2/KN	Y3/mm
1	12.5	20	15	15.68	0.334	8.39
2	10	15	9	12.73	0.276	9.01
3	15	10	12	17.27	0.103	5.98
4	12.5	15	12	15.19	0.215	9.17
5	12.5	20	9	15.61	0.347	7.98
6	12.5	10	9	14.78	0.134	8.39
7	15	15	15	18.15	0.187	6.79
8	10	20	12	12.98	0.359	10.39
9	10	10	12	11.8	0.171	11.44
10	15	15	9	18.44	0.199	5.33
11	12.5	15	12	14.23	0.206	9.29
12	15	20	12	18.36	0.318	5.67
13	10	15	15	12.33	0.223	10.27
14	12.5	15	12	13.96	0.215	9.68
15	12.5	15	12	14.77	0.214	9.91
16	12.5	15	12	15.27	0.217	9.44
17	12.5	10	15	15.08	0.121	9.18

. By optimizing the formulation of the slow-release anti-icing fog seal, a response surface regression equation was derived, which provides a quantitative relationship between the factors and the response variables.

Ice-melting performance:

$$Y_1=15.1+2.80X_1+0.46X_2-0.04X_3$$

(2)

Ice–road surface adhesion strength:

$$\begin{array}{c}{Y}_2=0.21-0.028X_1+0.1X_2-0.011X_3\\ +0.00675X_1{X}_2+0.01X_1{X}_3+0.0058{X_1}^2+0.019{X_2}^2+0.00205{X_3}^2\end{array}$$

(3)

Permeation depth:

$$\begin{array}{c}{Y}_3=9.5-2.17X_1-0.32X_2+0.49X_3\\ +0.18X_1{X}_2+0.05X_1{X}_3-0.095X_2{X}_3-0.88{X_1}^2-0.25{X_2}^2-0.77{X_3}^2\end{array}$$

(4)

3.2.2. Optimization of Slow-Release Anti-Icing Fog Seal Formulation

The effects of the interaction between the dosage of the slow-release anti-icing agent (X₁), the dosage of the waterborne epoxy resin modifier (X₂), and the dosage of the permeating agent (X₃) on the ice-melting performance, ice–road surface adhesion strength, and the permeability performance of the slow-release anti-icing fog seal are illustrated in Figure 10, Figure 11 and Figure 12, respectively.

As illustrated in Figure 10, under conditions where the penetrant concentration remains constant, no significant interaction is observed between the dosage of slow-release anti-icing agent (X₁) and the waterborne epoxy resin modifier (X₂). Specifically, an increase in the concentration of the slow-release anti-icing agent significantly enhanced the ice-melting efficiency of the material, demonstrating a direct and pronounced effect on the reduction in the ice layer thickness. In contrast, an increase in the dosage of the waterborne epoxy resin modifier results in a marginal decline in the ice-melting performance, although this effect was statistically insignificant. This indicates that, while the waterborne epoxy resin modifier exerted a limited influence on ice-melting properties, it may have contributed positively to other critical material characteristics, such as interfacial adhesion and long-term durability.

As depicted in Figure 11, under conditions where the penetrant concentration was held constant, the pull-out force exhibited a decreasing trend with an increase in the dosage of the slow-release anti-icing agent, while it demonstrated an increasing trend with a higher dosage of the waterborne epoxy resin modifier. The response surface analysis further revealed a synergistic interaction between the slow-release anti-icing agent and the waterborne epoxy resin modifier, as evidenced by the curvature of their contour lines. This suggests that the combined effects of these two components on ice–pavement adhesion strength were complex within a specific dosage range. The optimal ice–pavement adhesion strength was achieved when the dosage of the slow-release anti-icing agent was 10% and the dosage of the waterborne epoxy resin modifier was 20%, at which point the pull-out force attains its maximum value.

As demonstrated in Figure 12, when the dosage of the waterborne epoxy resin modifier was held constant, the permeability showed a pronounced decline with the increase in concentrations of the slow-release anti-icing agent. In contrast, the permeability initially increased and subsequently decreased with an increase in the dosage of the penetrant. The response surface analysis indicates that the interaction between the dosage of the slow-release anti-icing agent and the penetrant is the most significant. The optimal dosage range for the penetrant was identified as from 12.69% to 12.89%. Furthermore, the response surface analysis highlights that the interaction value between the slow-release anti-icing agent and the penetrant dosage is the highest among all tested variables, underscoring the critical role of their combined effects in determining permeability.

Through the iterative regression analysis of the predictive equation, the optimal formulation for the slow-release anti-icing fog seal was determined as follows: slow-release anti-icing agent:waterborne epoxy resin modifier:penetrant = 13:20:12. This formulation achieves an optimal balance among key performance metrics, including ice-melting efficiency, ice–pavement adhesion strength, and permeability.

3.3. Analysis of the Abrasion Resistance of Slow-Release Anti-Icing Fog Seal

The effects of different types of abrasion-resistant particles on the abrasion resistance of the slow-release anti-icing fog seal are presented in Figure 13. Basalt exhibits the best abrasion resistance, followed by limestone, with quartz sand showing the poorest performance. The mass loss trend for the abrasion-resistant particles of the three rock types is consistent: a rapid decrease within the first two hours, followed by a gradual leveling off. However, during the initial half hour, the mass loss of the fog seal using quartz sand is significantly greater than that of limestone and basalt. The cumulative mass loss values tended to stabilize after 2 h and were 17.24, 12.91, and 8.04 kg, respectively. Abrasion-resistant particles can be classified into acidic or alkaline stones based on their SiO₂ content. Stones with a SiO₂ content exceeding 65% are classified as acidic, while those with less than 55%, such as limestone, basalt, and gabbro, are considered alkaline. The interfacial interaction mechanisms between asphalt and aggregates of different chemical properties exhibit distinct characteristics. For alkaline aggregates, the CaO and MgO components on their surface formed a stable chemical bonding structure with the weakly acidic polar functional groups present in the asphalt. This chemical adsorption was characterized by strong interfacial adhesion, resulting in excellent resistance to debonding during accelerated loading conditions. In contrast, the interaction between acidic aggregates (primarily composed of SiO₂) and asphalt was predominantly governed by physical adsorption mechanisms. This type of adsorption was relatively weak in nature, making the interface more susceptible to failure under mechanical loading, ultimately leading to debonding phenomena [40].

The quartz sand used in this study contains more than 90% SiO₂, categorizing it as acidic, while both basalt and limestone are alkaline stones. Therefore, it can be concluded that the abrasion loss of limestone and basalt in the slow-release anti-icing fog seal is less than that of quartz sand. This indicates that alkaline stones form a stronger adhesion with emulsified asphalt compared to acidic stones. The stronger the stone’s adhesion to the asphalt, the greater its resistance to spalling and, consequently, the better its abrasion resistance. Furthermore, the density, hardness, and strength of the stone influence its adhesion to emulsified asphalt. Basalt in the slow-release anti-ice fog seal was superior to limestone in terms of wear resistance. The Mohs hardness and density of basalt are both greater than those of limestone, as shown in Table 6. This higher hardness and density value enabled the basalt particles to effectively resist fragmentation during wear, thereby improving the overall wear resistance of the fog seal. Therefore, basalt was selected as the wear-resistant particle in the slow-release anti-icing fog seal formulation in this study.

3.4. Analysis of the Skid Resistance of Slow-Release Anti-Icing Fog Seal

The pendulum value and texture depth (TD) of the slow-release anti-icing fog seal were measured using the British pendulum test and the sand patch test. Basalt was selected as the abrasion-resistant particle, and the test results are presented in Figure 14. As specified in the “Highway Asphalt Pavement Design Code JTG D50-2017” [41] and the “Technical Guidelines for Permeable Asphalt Pavement Surface Layer Regeneration and Repair” [42], the pendulum value of asphalt pavement is required to be at least 42, and the texture depth is required to be at least 0.55 mm. It can be observed from Figure 11a that the test results meet the specified requirements. Although surface roughness and texture depth were reduced following the application of the slow-release anti-icing fog seal, the results still remained within acceptable standards. This reduction is attributed to the inability of conventional dense road surfaces to fully absorb the waterborne epoxy-modified emulsified asphalt, resulting in a relatively smooth surface, which subsequently reduces texture depth and skid resistance. However, as wear continues, surface roughness and texture depth were further decreased until falling below the standard requirements. The roughness of the surface texture in fog seal layers under accelerated loading conditions exhibits a triphasic characteristic. In the initial phase (0–1 h), a pronounced morphological reconstruction occurs, characterized by anisotropic texture realignment and the rapid exfoliation of insufficiently consolidated aggregate particles. This process results in a substantial reduction in surface texture depth. During the intermediate phase (1–4 h), the surface texture demonstrates transitional stability. Surface particles undergo progressive displacement under the combined action of shear–rolling stress fields induced by tire loading. The rate of texture alteration diminishes significantly, by 70%–80%, compared to the initial phase. In the terminal phase (>4 h), critical structural degradation is observed, manifested through the development of macroscopic shear slip bands and localized spalling zones. Concurrently, the residual sealing material undergoes densification, forming a compacted surface layer through mechano-physical interactions.

4. Conclusions

A slow-release anti-icing fog seal was developed to enhance pavement safety and durability through optimized deicer application and improved wear resistance. However, this study did not sufficiently address environmental pollution, and future research will focus on evaluating the environmental impact of the anti-icing fog seal. Based on the findings, the following conclusions were drawn:

• Single-factor optimization determined that the optimal dosage ranges for slow-release anti-icing material, waterborne epoxy resin modifier, and permeating agent were 10%–15%, 10%–20%, and 9%–15%, respectively.
• The ratio of the various components of the slow-release anti-icing fog seal was optimized based on the response surface method, with the ice-melting performance, ice–road surface adhesion strength, and permeation properties as the response indicators, and the final optimal ratio of the slow-release anti-icing fog seal was determined: the slow-release anti-icing material dosage was 13%, the waterborne epoxy resin modifier dosage was 20%, and the permeating agent dosage was 12%.
• The wear resistance of the slow-release anti-icing fog seal decreased most significantly during the initial stages of accelerated loading, with alkaline basalt particles proving most effective in enhancing wear resistance.
• Initially, the anti-icing fog seal met the skid resistance and texture depth standards specified in JTG D50-2017 for asphalt pavements. However, surface roughness and texture depth gradually decreased due to the spalling of abrasion-resistant particles, followed by accelerated smoothness loss, contributing to further declines in pendulum value and texture depth.