1. Introduction
Pouring Semi-Flexible Pavement Material (PSFM) constitutes a composite material achieved by pouring cement-based grouting material into a porous asphalt mixture characterized by porosity levels typically falling within the range of 18% to 28% [
1]. Renowned for its exceptional load-bearing capacity, durability, and extensive fatigue life [
2,
3,
4], PSFM finds widespread application in pavement construction. Its efficacy in addressing challenges posed by high-temperature, heavy loads has been well documented [
5,
6]. The research and application of PSFM have experienced steady growth since its introduction in China during the 1980s [
7,
8]. As of 2022, 14 provinces and municipalities, including Jiangsu, Shanghai, Guangdong, and Hubei, have embraced PSFM as the wearing layer material in various urban infrastructures such as arterial highways, intersections, and bus stops. This adoption has notably mitigated issues related to rutting, waviness, and surge. In settings like service areas and toll stations, traditional cement concrete pavement has encountered challenges like peeling, exposed aggregate, and cracks, primarily due to frequent vehicle acceleration and deceleration. The integration of PSFM as an overlay in such locations has yielded remarkable results in engineering applications. In other projects employing PSFM for different layers, the pavement has demonstrated noteworthy resistance to rutting. This underscores the transformative impact of PSFM on enhancing the performance and longevity of pavement structures in diverse scenarios.
PSFM enhances heat tolerance and structural strength with the integration of pouring cement-based grouting material in which PSFM is applied as a pavement material in the pavement structure to give the pavement a rigid–flexible character; this pavement is called pouring semi-flexible pavement (SFP) [
9,
10]. However, its susceptibility to low temperatures renders the cement-based grouting material prone to brittleness, leading to shrinkage deformations and eventual cracking within the weak interface shared by asphalt and the cement-based grouting material [
11,
12]. Consequently, the low-temperature resilience of PSFM proves inferior to that of other asphalt mixtures [
13,
14]. In winter, cold regions experience low temperatures and substantial daily temperature fluctuations, contributing to material shrinkage and deformation within pavements. To assess the practical viability of SFPs in the cold region, a field investigation scrutinized SFPs in Liaoning province after years of operation. The SFPs predominantly featured a stone–mastic asphalt mixture (SMA-13) as the wearing layer material and PSFM as the binder layer material. A contemporaneous high-modulus asphalt pavement (HMAP), constructed using SMA-13 and a high-modulus asphalt mixture (HMM-20), served as a comparative reference.
Figure 1 visually delineates the identical diseases present in both pavements. Compared with the HMAP, detailed further in
Table 1, the investigation revealed that the longitudinal crack rate of the two SFPs measured 54 m/km and 218 m/km, marking a 38% reduction. Additionally, the transverse crack rate increased by 14 lines/km and 34 lines/km over the HMAP. Rutting experienced a decrease of 3 mm. While the area exhibiting block cracks in the SFPs was smaller than that of the HMAP, it is notable that one of the SFPs manifested alligator cracking. This investigation underscores PSFM’s potential to enhance a pavement’s rutting resistance, albeit at the expense of heightened susceptibility to temperature fluctuations.
In understanding the critical factors influencing the cracking propensity of SFP, it becomes imperative to delve into the underlying mechanisms governing their cracking behavior. Utilizing image processing techniques, the spatial arrangement of the constituent phases—comprising materials and voids—within PSFM has been discerned and segmented into grids to facilitate numerical simulations. Wang [
15] noted that the volumetric changes, particularly the expansion or contraction of the cement-based grouting material, engender tensile stresses within the composite material. Notably, lower temperature-induced contractions pose a significantly higher risk to the structural integrity of PSFM. Moreover, Jiang [
16] established the influence of dynamic loading on the mechanical properties of PSFM, leading to stress concentrations and fatigue-induced damage, particularly at weak areas of contact between the asphalt and aggregate. Concurrently, Xiong [
17] developed an ANOVA model, corroborating the significant impact of surface temperature on the cracking behavior of PSFM. When the shrinkage stress surpasses the material’s tensile strength, it invariably leads to impaired interlayer bonding and subsequent cracking [
18]. Hence, to enhance the cracking resistance of SFP, especially in cold regions, and thereby extend the material’s service life, a thorough analysis of low-temperature stress within the pavement structure is imperative before incorporating PSFM.
In anticipation of undertaking a low-temperature stress analysis of SFP, a comprehensive examination of the material properties of PSFM is imperative. Porous asphalt mixtures exhibit stress relaxation, and the relaxation modulus serves as a prevalent indicator of the relaxation properties inherent in linear viscoelastic materials [
19,
20,
21,
22]. Although various test methods are available for validating the relaxation modulus, the intricacy and challenges associated with the relaxation test process render it an incomplete measure of the viscoelastic characteristics of asphalt mixtures [
23,
24,
25]. To address this limitation, this study ascertains the relaxation modulus of PSFM through dynamic modulus testing, employing the principle of time–temperature superposition [
26,
27,
28]. This method involves the transformation of frequency domain–dynamic modulus relationship curves into time domain–relaxation modulus principal curves expressed using the Prony series. These curves serve to delineate the constitutive relationship of respective mixtures within the linear viscoelastic range [
29,
30]. This holistic methodology significantly advances our comprehension of the viscoelastic characteristics inherent in PSFM and substantively contributes to a more sophisticated approach to pavement structural design, particularly within the framework of addressing low-temperature stress considerations for SFP.
It becomes crucial to integrate the temperature shrinkage coefficient of the cement-based grouting material into the overall temperature stress analysis [
31]. Hao [
32] conducted a thorough investigation into the temperature shrinkage coefficient of PSFM through numerical modeling. The findings reveal that the incorporation of cement-based grouting material does not impart any significant alteration to the overarching temperature shrinkage coefficient of PSFM. However, the low-temperature cracking of PSFM is mainly caused by cement-based grouting material. Therefore, it is noteworthy that the temperature shrinkage coefficient of PSFM exerts a direct influence on the temperature shrinkage strain experienced by the wearing layer, consequently impacting the resultant low-temperature stress.
The analysis of SFP low-temperature stress is based on the analysis method of asphalt pavement. Hills and Brien [
33] approached their study on the assumption of isotropic pavement materials, positing a uniform distribution of temperature stress with a seamless connection between layers. Zheng [
26] adopted an iterative finite element approach, establishing an equation for the temperature stress field under continuous cooling conditions. This approach facilitates the calculation of stress distribution with variations in temperature. In a related vein, Geng [
34] proposed a method for analyzing temperature stresses in asphalt pavements under dynamic loading. This method, rooted in the viscoelastic theory of asphalt mixtures, accounted for the nonlinear variation in temperature with time and depth of the asphalt layer, thereby deriving temperature stresses at different locations and temperatures. Collectively, these studies contribute to a comprehensive understanding of temperature stress analysis methodologies for asphalt pavements, with implications for both design and practical applications. Si [
35] leveraged the viscoelastic properties inherent in asphalt mixtures to formulate a nonlinear governing equation for coupled heat–liquid force. This formulation involved a comparative analysis with a single stress field, revealing that internal stresses within the pavement exhibit an augmentation when temperature and water infiltration considerations are incorporated. In a parallel exploration, Zhang [
36] contributed to the field by developing a numerical computational model characterizing the temperature stress field over time. Notably, this model extends the understanding of material properties by integrating the relaxation properties of the asphalt surface material as a mechanical parameter for finite element analysis. Additionally, Fang [
20] made noteworthy contributions by refining the calculation formula for cumulative temperature stress in asphalt pavement. The comprehensive elucidation incorporates considerations of asphalt stress characteristics, presenting a thorough process and calculation formula. Emphasizing the material’s shrinkage strain underscores its greater influence on performance compared with vehicle loads.
In synopsis, extant investigations have exhibited a dearth of comprehensive analysis concerning temperature stresses in SFP. Traditional parameters, exemplified by the dynamic modulus, prove inadequate for ensuring precise damage detection and the evaluation of pavement structure performance. Consequently, there exists a compelling need for further inquiry to enhance the accuracy of pavement performance assessment.
In the present study, we address this gap by incorporating the measured relaxation modulus and temperature shrinkage coefficient of PSFM under low-temperature conditions. Utilizing these data, we develop a finite element simulation in COMSOL for the pavements that introduce PSFM. This simulation model facilitates the evaluation of low-temperature stress distribution in pavements with diverse structures exposed to varying temperature conditions. A comparative analysis is executed employing a representative asphalt pavement structure. The purpose of this study is to explore the subtle effects of PSFM application layer and thickness on pavement low-temperature stress caused by low temperature. The outcomes of this study offer valuable insights and guidance for the nuanced design of SFP structures, particularly in cold regions. By systematically addressing the limitations of existing approaches, this research contributes to advancing understanding and design considerations for SFP. The main content of this study is shown in
Figure 2.
4. Low-Temperature Stress Analysis of SFP
For the low-temperature stress analysis of SFP, different combinations of pavement structures are designed by first considering different application layers and thicknesses of the PSFM, and the pavement structure model is created by using the COMSOL Multiphysics 5.6 finite element analysis software to simulate the temperature field distribution of the whole pavement structure under different temperature conditions, respectively. The low-temperature stresses generated in the pavement structure by the simulated temperature distribution are analyzed using appropriate stress analysis techniques.
4.1. Finite Element Modelling
Before the low-temperature stress analysis of SFP, the finite element modeling of pavement structure is carried out to determine the geometric shape of pavement structure and the material properties of each layer. The accuracy of the analysis is increased by meshing. In order to meet the requirements of the actual pavement structure, the boundary conditions are specified for the model.
4.1.1. Structural Form
The primary objective of this investigation is to enhance the resistance of asphalt pavements to low-temperature cracking in cold regions by strategically designing pavement structures that incorporate PSFM. Departing from a conventional double-layer asphalt pavement structure as the baseline, PSFM is judiciously integrated into both the wearing layer and the binder layer. To explore the influence of varying layer thicknesses, 11 distinct pavement structure configurations were formulated, as detailed in
Table 6. These configurations were systematically subjected to simulation and analysis. Notably, structures denoted as A to E incorporate PSFM in the wearing layer, while those labeled as a to e feature PSFM in the binder layer. This comprehensive approach aims to assess the effectiveness of PSFM in mitigating low-temperature cracking across diverse pavement configurations, contributing valuable insights for SFP performance in cold climates.
4.1.2. Geometric Modeling
In the analysis of temperature-induced stresses, the theoretical framework for numerical simulation rests upon the principles governing a viscoelastic layered system in the context of road structures. A comprehensive three-dimensional finite element model is devised, guided by specific assumptions [
41]. In this model, the pavement-wearing layer is assumed to exhibit uniform isotropic viscoelastic behavior, while the remaining layers are treated as linearly elastic. Assumptions also encompass seamless bonding and continuous displacement between individual structural layers, ensuring consistent interlayer temperature and heat flux. The analytical approach disregards lateral variations in the pavement temperature field and simplifies heat flow as unidirectional, perpendicular to the pavement direction. Notably, it neglects the impact of temperature alterations on the thermal conductivity of each layer of material.
Acknowledging the strip-like configuration of the pavement structure, characterized by infinite longitudinal (driving direction) and depth dimensions but relatively confined transverse dimensions, the challenge arises in defining finite dimensions for the computational model. Due to practical limitations, infinite dimensions cannot be practically employed in the modeling process. Hence, the computational model’s dimensions are meticulously determined to strike a balance between computational accuracy and complexity. Adhering to the precision requirements of the study, the model’s pavement plane direction is set at a 4 m × 4 m square, incorporating layer thicknesses as per
Table 7 and a soil depth of 5 m. This delineates the establishment of a three-dimensional geometric representation of the pavement structure, as illustrated in
Figure 9.
4.1.3. Material Parameters
Based on the above test results and the pavement material parameter data from the cited studies [
42,
43], the material parameters collated in
Table 8 were imported into the geometric model in
Figure 8 (
Section 3.2) for subsequent low-temperature stress analysis.
4.1.4. Boundary Condition
Symmetric boundary conditions have been meticulously imposed on the geometric model depicted in
Figure 8, representing the pavement structure. Defined displacements are judiciously specified in both the transverse and longitudinal directions to ensure a comprehensive characterization of the system’s response. The lower boundary is subjected to fixed conditions, thereby constraining its movement, while the upper boundary of the pavement structure is intricately configured to facilitate surface-to-surface radiation heat transfer mechanisms.
To establish a well-defined thermal environment, the initial temperature at the bottom boundary is rigorously set to 0 °C, emphasizing a controlled starting point. Concurrently, the remaining boundaries are systematically demarcated as thermally insulated, ensuring an encapsulated and controlled thermal regime within the computational domain.
In regions where the load interacts with the pavement, a judiciously chosen dense mesh is employed, enhancing computational resolution and precision to accurately capture localized effects. Conversely, in areas devoid of direct contact, a strategically sparse mesh is implemented, optimizing computational efficiency without compromising the fidelity of the numerical simulation. This meshing strategy aims to strike a balance between computational resource utilization and the accurate representation of physical phenomena within the pavement structure.
4.2. Low-Temperature Stress Calculation Method
This study employs the COMSOL finite element software to ascertain temperature-induced stresses in asphalt pavement structures. The investigation adheres to the foundational principles of heat conduction theory, incorporating considerations of the thermal properties intrinsic to the structure. Furthermore, the initial and boundary conditions are meticulously considered during the computational process, where temperatures at diverse points within the structure are computed for each temporal instance. This computational procedure serves to establish the internal temperature field of the pavement.
In the subsequent analysis of the temperature field, it is acknowledged that setting initial temperatures uniformly to 0 °C, while a common practice, may not precisely capture the authentic temperature distribution. Upon the stabilization of the internal temperature field following a designated period of temperature influence, it is employed as the foundational input for the subsequent low-temperature stress analysis.
In the transient finite element analysis considering the stress relaxation of the pavement material and the variable temperature field, this study comprehensively considers and finds that the temperature field changes slowly. It first considers the stress relaxation effect of the material by setting the step size [0, 0.01, 1] and transient analysis of the pavement structure. After considering the temperature field variation, a larger step size is later set, and a 24 h temperature field analysis is carried out by setting every hour as a unit.
Variations in regional climates engender considerable diversity in pavement temperature fields, consequently affecting the internal low-temperature stress experienced by asphalt pavements. Recent investigations have focused on examining the temperature distribution within asphalt pavements in cold regions. These studies specifically scrutinize the average low temperatures during winter in such regions, alongside exploring extreme low-temperature conditions. The environmental attributes pertinent to these investigations are delineated in
Table 9.
4.3. Low-Temperature Stresses in SFP
4.3.1. Effect of Different Applied Layers on Low-Temperature Stresses
In the context of varying temperature conditions, an examination of low-temperature stresses across different layers of the pavement structure is conducted under conditions representing the most unfavorable scenarios. As depicted in
Figure 10, it is evident that the wearing layer is particularly susceptible to experiencing heightened low low-temperature stress. Progressing in the depth direction, the influence of temperature fluctuations and material properties on low-temperature stresses diminishes, exhibiting minimal impact on the base and subbase layers.
Comparatively, when juxtaposed with the typical pavement structure, the low low-temperature stress on the road surface under T1 is mitigated by 0.08 MPa in Comparative Structures A. Furthermore, the low low-temperature stress at the bottom of the wearing layer shows a reduction of 0.06 MPa, while the low low-temperature stress at the bottom of the binder layer decreases by 0.05 MPa. Similarly, under T2 conditions, Comparative Structures A manifest a reduction of 0.14 MPa in road surface low low-temperature stress, a decrease of 0.07 MPa at the bottom of the wearing layer, and a 0.05 MPa decline in low-temperature stress at the bottom of the binder layer.
In contrast, Comparative Structures a, when compared with the reference typical pavement structure, exhibit nuanced variations in low-temperature stresses. Specifically, under T1 conditions, the low-temperature stress at the road surface increases by 0.05 MPa, while at the bottom of the wearing layer, there is an increment of 0.03 MPa. Conversely, the low-temperature stress at the bottom of the binder layer decreases by 0.02 MPa. Similarly, under T2 conditions, the low-temperature stress at the road surface rises by 0.11 MPa, the bottom of the wearing layer experiences an increase of 0.08 MPa, and the bottom of the binder layer sees a reduction of 0.04 MPa.
Furthermore, an assessment of low low-temperature stress at the same temperature reveals notable distinctions when PSFM is employed as the wearing layer material. Specifically, the low low-temperature stress is 4.73% less than that of SMA-13 in the typical pavement structure, and concurrently, the low low-temperature stress on the internal binder layer material is reduced by 4.91%. Conversely, when utilized as the binder layer material, the low low-temperature stress is 2.61% less than that of AC-20 in the typical pavement structure. However, it results in a 3.5% increase in the low low-temperature stress on the wearing layer of SMA-13.
In summary, the analysis results indicate that employing PSFM as the wearing layer material minimizes low low-temperature stress experienced by the pavement structure at the same temperature. Conversely, when utilized as the binder layer material, while it reduces low-temperature stress within the binder layer, it concurrently elevates low-temperature stresses in the wearing layer material, rendering it more susceptible to low-temperature cracking.
4.3.2. Effect of Different Surface Thicknesses on Low-Temperature Stresses
In this section, the pavement structure configuration outlined in
Table 7 is employed, utilizing PSFM as both the wearing layer and binder layer material. The analysis focuses on varying the thicknesses of the wearing layer to assess the low-temperature stress distribution within the pavement structure under T
2 conditions. It is notable that altering the wearing layer material has minimal impact on the low-temperature stresses at the bottom of the roadbed and the sub-base layer. Therefore, the investigation in this section concentrates solely on the low-temperature stress distribution within the wearing layer.
The findings indicate that, when the thickness of the PSFM wearing layer is increased from 4 cm to 6 cm within the asphalt pavement configuration, depicted in
Figure 11, several changes in low-temperature stresses are observed. Specifically, as the wearing layer thickness escalates, the surface low-temperature stress rises by 0.05 MPa, while the low-temperature stress at the bottom of the wearing layer decreases by 0.04 MPa. Simultaneously, the low-temperature stress at the bottom of the binder layer decreases by 0.02 MPa in correlation with the increase in the wearing layer thickness. Additionally, maintaining a constant wearing layer thickness while increasing the binder layer thickness from 6 cm to 8 cm yields specific variations in low-temperature stresses. Consequently, the low-temperature stress at the bottom of the binder layer decreases by 0.02 MPa in tandem with the increase in wearing layer thickness. Similarly, keeping the wearing layer thickness constant and augmenting the binder layer thickness from 6 cm to 8 cm manifests distinct alterations in low-temperature stresses. This scenario results in an increase of 0.04 MPa in road surface low-temperature stress. Meanwhile, the low-temperature stress at the bottom of the wearing layer decreases by 0.02 MPa, and the low-temperature stress at the bottom of the binder layer decreases by 0.01 MPa.
In the utilization of PSFM as the binder layer, as illustrated in
Figure 12, an examination of thickness variations from 6 cm to 8 cm reveals noteworthy changes in low-temperature stresses across different layers. Specifically, there is an observed increase of 0.06 MPa in the low-temperature stress at the road surface, concomitant with a decrease of 0.03 MPa in the low-temperature stress at the bottom of the wearing layer, and a decrease of 0.02 MPa in the low-temperature stress at the bottom of the binder layer. Conversely, maintaining the thickness of the binder layer constant while increasing the thickness of the wearing layer from 4 cm to 6 cm results in an elevation of 0.06 MPa in road surface low-temperature stress. Simultaneously, a decrease of 0.05 MPa in the low-temperature stress at the bottom of the wearing layer and a decrease of 0.01 MPa at the bottom of the binder layer is noted.
The analysis yields the conclusion that augmenting the thickness of the pavement-wearing layer correlates with an escalation in thermal stress on the pavement surface. However, the influence of varying the thickness of different layers on internal low-temperature stress is nuanced. Specifically, when PSFM serves as the binder layer, an increase in binder layer thickness introduces differences in modulus, leading to an augmentation of low-temperature stress in the wearing layer (SMA-13). Conversely, maintaining the thickness of the binder layer while increasing the thickness of the wearing layer proves effective in mitigating internal low-temperature stress, albeit at the expense of an increase in low-temperature stress at the road surface.
5. Discussion
As a pavement material, PSFM has many advantages, which makes it widely used. First, the initial cost of PSFM is higher, but the long-term maintenance cost is lower, which can save maintenance and repair costs. The initial cost of asphalt mixture is lower, but the long-term maintenance cost is higher, which requires more frequent repair and maintenance. In addition, PSFM also has a longer service life and better durability, which can be used in a wider temperature range and can better adapt to climate change and traffic load changes. In the field of road engineering, PSFM has often been utilized to alleviate rutting in asphalt pavements subjected to high temperatures, either as a wearing layer material or below. However, when used as the binder layer material in cold climates, an elevation in temperature-induced cracks has been detected.
To rectify this problem and enhance the crack resistance of SFP at low temperatures, a series of comprehensive studies (referenced as [
44,
45,
46,
47]) have been conducted. These investigations focus on enhancing the innate crack resistance of PSFM through various interventions. The addition of additives to cement-based grouting material involves tailored modifications to improve crack resistance. Similarly, the introduction of emulsified asphalt seeks to enhance low-temperature crack resistance by modifying the binder composition for improved flexibility in cold conditions. Efforts are also directed toward optimizing the structure of porous asphalt mixtures, with meticulous adjustments made to the arrangement of aggregates and void spaces within the mixture to improve crack resistance.
However, it is important to recognize that these efforts, although effective in improving low-temperature crack resistance, often involve a trade-off. The optimization measures used to mitigate cold-induced cracking can inadvertently reduce resistance to high-temperature deformations. This highlights the complexity of addressing different performance criteria in asphalt pavement design, requiring a careful and comprehensive approach to tackle the multifaceted challenges presented by varying environmental conditions.
In studies examining crack resistance in asphalt pavements, finite element software is commonly employed to simulate the distribution of internal low-temperature stress within the pavement structure. This approach aims to forecast asphalt mixture shrinkage at low temperatures [
48,
49,
50,
51]. However, there is a notable gap in low-temperature stress analysis specifically focused on the use of PSFM. This lack of understanding presents challenges in proposing precise design parameters during the pavement structure design phase, as the incorporation of multiple materials introduces complexity. Consequently, pavement structures are frequently inadequately verified, impeding the optimization of pavement designs.
Although PSFM is effective in mitigating various issues as a binder layer material, its usage in cold regions has been found to result in a significant increase in transverse cracks on the wearing layer due to low low-temperature stress. To address low-temperature cracking, some pavement structures use PSFM as the binder layer material while increasing the thickness of the wearing layer to reduce low-temperature stress within the pavement structure. However, this results in elevated low-temperature stress on the pavement surface. These complexities can be addressed through material development strategies aimed at enhancing the crack resistance of the SMA-13 wearing layer.
This analysis focuses on the stress relaxation of asphalt mixtures and the thermal shrinkage strain of cement-based grouting material, but further refinement is necessary to enhance material property analysis rigor. This involves a meticulous examination of bonding effects between cement-based grouting material and asphalt at microscopic levels across different temperatures, considering factors such as grout shrinkage. Assessing the sensitivity of various material parameters to temperature-induced stresses is also crucial. To achieve these objectives, this study conducts a comprehensive low-temperature stress analysis based on indoor experimental data. By incorporating precise material parameters, the goal is to establish a robust foundation for the widespread application of SFPs in cold regions.
6. Conclusions
This investigation uses PSFM as either the wearing layer material or binder layer material, exploring low-temperature stress distribution through different combinations of layer thicknesses and structural configurations. COMSOL finite element simulation is employed to analyze these behaviors and thermal interactions, known for its efficacy in capturing intricate structural behaviors.
(1) When PSFM is used as the wearing layer material, it experiences 4.7% lower low-temperature stresses compared with a conventional pavement structure under the same thermal conditions. It also effectively reduces low-temperature stress on the binder layer material by 6.4%. Conversely, when used as the binder layer material, PSFM reduces low-temperature stress by 3% compared with the binder layer of a typical pavement structure (AC-20). However, it is important to note that the low-temperature stress on the SMA-13 wearing layer increases by 3.5%, making it more susceptible to low-temperature cracking in this specific layer.
(2) Increasing the thickness of the pavement wearing layer intensifies surface low-temperature stress, but the effect on internal low-temperature stress varies across different layers. When PSFM is used as the wearing layer material, its resistance to low-temperature stress increases with thicker layers, leading to a rise in surface low-temperature stress and an increased risk of temperature-induced cracks. However, internal low-temperature stress decreases by 1.3%. Conversely, when PSFM is used as the binder layer material, increasing the binder layer thickness results in higher low-temperature stress in the SMA-13 wearing layer due to differences in modulus. Maintaining the binder layer thickness while increasing the wearing layer thickness reduces internal low-temperature stress by 1.3% while raising pavement surface low-temperature stress by 1.9%.
To address low-temperature cracking in colder climates, the low-temperature stress analysis suggests using PSFM as the binder layer material and increasing the thickness of the wear layer. This adjustment significantly reduces low-temperature stresses in the wearing layer, effectively mitigating the risk of low-temperature cracking.