Black ice remains a difficult pavement hazard because it is thin, transient and visually elusive, yet it can rapidly compromise surface friction. This study develops a microencapsulated phase change asphalt mixture (MPCAM) for delaying black ice formation and, more importantly, establishes electrical conductivity monitoring as a quantitative means of tracking the freezing of thin surface water films. A microencapsulated phase change material (MPCM), composed of an n-tetradecane core and SiO₂ shell, was synthesised, characterised and incorporated into SMA-13 asphalt mixture at 0%, 1.0%, 1.5% and 2.0% by mass of the total mixture. The thermal response, freezing behaviour, ice-pavement adhesion strength and skid resistance of the mixtures were evaluated. During cooling from 20 °C to −15 °C, the mixture containing 2.0% MPCM maintained an internal temperature up to 5.66 °C higher than the control, indicating effective latent-heat release during phase change. The conductivity response captured the abrupt loss of liquid-water continuity during freezing, enabling both the onset and completion of black ice formation to be identified. The ability to distinguish these two freezing stages is an important methodological feature of the study. The maximum freezing delay reached 95 min for a 1 mm water film and 100 min for a 2 mm water film. MPCM also reduced ice-pavement adhesion and improved skid resistance under icy conditions. These findings show that MPCAM is best understood not as a material for preventing sustained icing, but as a passive pavement technology for delaying short-duration black ice formation around the freezing point.

Industrial cyber-physical systems (ICPS) for transportation infrastructure require accurate, data-driven condition assessment for intelligent monitoring and maintenance. Yet pavement responses under dynamic loading are highly nonlinear, causing conventional optimizers and learning models to stagnate in local optima. This study proposes two PSO variants-Inverse PSO (INV-PSO) and Chaotic Inverse PSO (CINV-PSO)-for robust global optimization. INV-PSO is supported by a convergence theorem and improves exploration via inverse updates, while CINV-PSO further introduces chaotic maps to enhance escape from local minima and maintain diversity. Both optimizers are used to train a lightweight Extreme Learning Machine (ELM) for predicting asphalt pavement deflection basin area from Falling Weight Deflectometer (FWD) measurements and related operational variables. Experiments show that INV-PSO-ELM and CINV-PSO-ELM outperform classical machine learning baselines and PSO-ELM in accuracy and stability. The proposed framework provides an efficient and practical cyber-physical solution that reduces the need for frequent on-site deflection testing while preserving high-fidelity pavement condition estimation.

Incorporating phase change materials (PCMs) into asphalt mixture can effectively improve high-temperature rutting resistance. However, existing conventional wheel tracking test (CWTT) procedures apply a constant test temperature (60 °C), which does not reflect the phase transition process of PCMs. The suitability of CWTT for evaluating the rutting resistance of PCMs-modified asphalt mixtures (P-MAM) remains unclear. If the CWTT is unsuitable for evaluating the rutting resistance of P-MAM, an improved wheel tracking test (IWTT) must be proposed for accurate rutting resistance assessment. In this study, PEG/SiO2 with different molecular weights were prepared and incorporated into asphalt mixture slabs. CWTT results (internal temperature, dynamic stability, rutting depth) were analyzed to identify the test limitations. An IWTT methodology was proposed which takes into account the whole phase transition process of PCMs over the temperature range of 40–70 °C. The IWTT protocol was subsequently applied to eight P-MAM specimens (including single- and double-layer configurations) to determine the most effective PCM incorporation strategy. Results indicate that the CWTT cannot reliably evaluate the rutting resistance of P-MAM. The IWTT successfully captures the thermal–mechanical coupling behavior of PCMs across phase transition process and provides reliable evaluation results. For single-layer P-MAM slabs, the addition of PEG6000/SiO2 has the best rutting resistance. For double-layer P-MAM slabs, adding PEG6000/SiO2 to the upper layer exhibits the optimal rutting resistance.

Planting concrete is a composite material used for erosion control on roadbed side slopes. However, excessive concrete thickness creates an unfavorable environment that prevents the survival of some grass species. This study aims to optimize the thickness and grass species of planting concrete. The stress scenarios of planting concrete, including pedestrian loads and frost heave stress, were analyzed. The maximum internal stress under pedestrian loads and the frost heave stress during freezing were determined using finite element analysis and frost heave tests, respectively. Nine groups of planting concrete specimens with different porosities and water-cement ratios were prepared and tested. The measured compressive and splitting tensile strengths were compared with the maximum stress of planting concrete to determine the optimal mix proportion. Using the optimal mix, planting concrete specimens with three thicknesses were prepared, and six common grass species were selected for planting experiments. Vegetation coverage, plant height, root length, root number, and root biomass were measured for each grass species at three thicknesses to determine the optimal thickness and grass species. The results show that the maximum tensile stress of planting concrete under pedestrian loads and frost heave stress is 0.86 MPa. The optimal porosity and water-cement ratio are determined to be 30% and 0.33, respectively. Ryegrass exhibits the highest vegetation coverage and plant height, thereby determining that ryegrass is the optimal grass species. Planting concrete of 4 cm thickness demonstrates the best root development, thereby determining that 4 cm is the optimal thickness. These findings provide a scientific basis for optimizing ecological slope protection with planting concrete.

Owing to the limited aggregate resources and economic concerns, more and more asphalt pavement surfaces have to use coarse aggregates with a lithology combination. However, the texture deterioration characteristics are still unknown for asphalt pavement surface with a lithology combination of coarse aggregates under traffic loadings. This study aims to investigate the texture depth deterioration of asphalt mixture prepared with varying lithological coarse aggregates by laboratory polishing tests combined with raster scanning tests. The morphological characteristics and chemical compositions of three lithology types of coarse aggregates (i.e., limestone, basalt, and diabase) were quantified by the Aggregate Image Measurement System II and X-ray fluorescence, respectively. Three-dimensional (3D) surface texture of three types of asphalt mixture (asphalt concrete-13, stone mastic asphalt [SMA]-13, and open graded friction course-13) were reconstructed using raster scanning method and validated by computed tomography scanning method. Different combinations of mineral Laboratory accelerated polishing tests were conducted on the compacted slabs. The crosssectional profiles of slabs after different polishing times were compared and mean profile depth was calculated. Results show that the raster scanning is a low-cost effective method for reconstructing 3D surface texture and cross-sectional profile of asphalt mixture. As the polishing times increase, the altitude of the peak positions in the cross-sectional profile shows a rapid and then slow decrease. Using varying lithology aggregates could not only alter the initial texture depth of asphalt mixtures but also have an obvious effect on texture deterio of 13.2 mm, coarse aggregates consisting of 4.75-9.5-mm basalt, 9.5-13.2-mm diabase, and 13.2-16-mm basalt have a superior abrasion resistance.

Pavement skid resistance deterioration is primarily caused by morphology attenuation in coarse aggregates under tire polishing. Current research has predominantly examined loose aggregates, while the three-dimensional (3D) morphology attenuation of aggregates on asphalt mixtures surface under tire polishing remains poorly characterized. To address this issue, this study introduces an innovative approach combining grating projection scanning with two novel indexes - maximum principal curvature (MPC) for angularity and surface projection expansion rate (SPER) for texture to quantitatively characterize morphology attenuation of tire polished aggregates. In this study, four lithology types of coarse aggregates (limestone, basalt, andesite and diabase) in SMA-13 mixtures were evaluated against Los Angeles-abraded loose aggregates using both traditional (sphericity, shape factor) and proposed indices. Results show that the grating projection scanning is an effective method for reconstructing 3D morphology of coarse aggregates. Polishing treatment caused significant angularity reduction in SMA-13 aggregates, while the surface textures are slightly reduced and the shapes are almost unchanged. Compared with sphericity and shape factor, the MPC and SPER are more sensitive to the polishing of coarse aggregate on SMA-13 slab surface and suitable to quantitatively evaluate the morphology attenuation of coarse aggregate. The morphology attenuation resistance of four lithology types of coarse aggregates is in order of limestone < diabase approximate to andesite < basalt.

This study explored the phase change composite material (PCCM) to regulate the temperature of porous cement concrete (PCC), thus preventing PCC pavement from freeze-thaw (FT) deterioration. White carbon black was used to absorb tetradecane to synthesize the PCCM. The thermal stability, chemical stability and anti-leakage capacity of PCCM were evaluated. PCCM with varying dosages were incorporated into PCC to prepare phase change porous cement concrete (PCPCC). The internal temperature of PCPCC subjected to freezing and thawing was measured to evaluate the temperature regulation capacity. Results indicate that the designated PCCM has satisfying thermal and chemical stability. 3% PCCM is suggested as an optimal dosage to balance the PCPCC strength and temperature regulation. Compared with PCC, PCPCC shows superior temperature regulation capacity with a maximum temperature increasing of 6.7degree celsius in freezing process. The incorporation of PCCM is also able to make the frozen PCC thawing earlier and faster.

Chloride-based pavement lowers freezing point of pavement surface and delays ice formation by releasing chloride ions. However, the long-term effectiveness of chloride filler has not been well-understood. This study combined the experimental and simulation methods to investigate the long-term releasing characteristics of chloride ions inside chloride-based mixtures. In this study, two types of chloride-based asphalt mixtures (AC-13 and OGFC-13) were prepared with Mafilon (MFL) and immersed in deionized water. The electrical conductivity tests were conducted on leaching water to evaluate the long-term releasing characteristic of chloride ions. The migration simulation was carried out on MFL AC-13 subjected to wet-dry cycles to explore the migration characteristics of chloride ions inside MFL AC-13 mixture. Results show that chloride ions experiences a rapid release within 30d in water, followed by a gradual and sustained release. Half of the chloride ions in mixture containing 70 % MFL will released into water after immersion for 278d at 20 degrees C degrees C or 74d at 60 degrees C, degrees C, respectively. The long-term release of chloride ions can be significantly improved by increasing the MFL dosage in asphalt mixtures. Chloride ions in mixture surface preferentially released into leaching water, resulting in a higher concentration of residual chloride in core of the mixture. During the drying phase, the chloride ions concentration throughout the asphalt mixture tends to become uniform as drying time increases. The findings achieved in this study would benefit and promote the better use of MFL in anti-icing pavement.

Anti-icing asphalt pavements can delay surface icing by reducing the freezing point to a certain degree. This study conducted the laboratory and field investigation to compare the anti-icing effectiveness and mechanical performance of two anti-icing stone mastic asphalt (SMA). Two types of anti-icing modifiers (e.g. LX II and MFL) were used in SMA respectively. The electrical conductivity test, ice melting test, and outdoor snow melting test were conducted on fresh and aged LX II SMA and MFL SMA, respectively, to evaluate the anti-icing effectiveness. The effect of anti-icing additives on high-temperature stability, low-temperature cracking resistance, and water stability of SMA were also analyzed. Two in-situ pavements were constructed using LX II SMA and MFL SMA. The anti-icing effectiveness of LX II and MFL pavement were compared by the observation of ice formation and snow accumulation on pavement surface on snowy days. The results showed that after long-term aging of anti-icing SMA, the chloride in LX II and MFL was more easily released. Two anti-icing additives had no significant effect on the water stability of SMA, and only slightly reduced high-temperature stability and low-temperature cracking resistance. LX II presented better anti-icing performance than MFL in both laboratory and field conditions.

An adequate pavement texture that provides sufficient brake friction is critical for drive safety. Thus, it is essential to quantify the pavement texture and friction efficiently and accurately. So far, the close-range photogrammetry (CRP) method has been manifested as a promising one. Nonetheless, related measurement parameters have not been well optimized toward its extensive promotion. For this reason, varying measurement parameters of CRP method were thoroughly discussed and optimized in this study. Additionally, the optimized CRP method was further validated using the sand patch test and X-ray computed tomography scan method. Based on this, the estimation of friction coefficients for asphalt concrete (AC-13), stone mastic asphalt (SMA-13), and open graded friction course (OGFC-13) were carried out. The results indicate the following: (1) the optimized CRP method was able to adequately feature the pavement macrotexture; (2) the mean texture depth derived from the CRP method was equivalent to the texture depth measured from sand patch method; in addition, (3) the OGFC asphalt mixture was superior to the SMA and AC asphalt mixtures in terms of the friction coefficients. The optimized CRP method could bring bright prospects for future measurements of pavement texture.

So far, chloride-based particles have been extensively used for the improvement of anti-icing performance of dense-graded asphalt pavement. However, its utilisation in the open-graded asphalt mixtures has not been sufficiently qualified. For this reason, this study prepared porous asphalt mixtures (PAM) using two types of chloride-based particles, namely Mafilon (MFL) and Lvxin II (LX II). In what follows, mechanical properties, anti-icing and de-icing performance of PAMs were respectively investigated. Concerning the mechanical properties of PAMs, the uniaxial compression test, Marshall test, rutting test, Cantabro loss test, as well as moisture stability were conducted. Anti-icing performance was estimated by the measurement of conductivity and freezing point for the leaching water of PAMs. Meanwhile, the de-icing performance of PAMs was quantified by the inclined shearing test and melting monitoring. Although the incorporation of MFL or LX II deteriorated the mechanical performance of PAMs to some extent, the results indicated that all mechanical indicators can satisfy the application requirement. Considering significant improvement in anti-icing and de-icing performance, it can be concluded that the use of chloride-based particles in the PAM is promising.

Frost heaving stress (FHS) is one of the main causes of freeze-thaw (FT) damage in porous cement concrete. This study customized a device for the measurement of FHS in the laboratory. Firstly, rodding, vibration, and static compaction methods were compared for the preparation of porous cement concrete in terms of the air void characteristics and air void distribution. Based on the proposed measurement device, the influence of curing time, air void, saturation degree, and freeze-thaw cycles on the FHS evolution were discussed, respectively. Besides, the release characteristics of FHS in the thawing process were also characterized. The results indicated that the evolution of FHS in the freezing process can be divided into three stages that accounted for the thermal contraction, phase transformation of water, and the end of phase transformation. The FHS of porous cement concrete can be reduced through the extension of curing or reduction of air void content. In general, the increase of saturation degree induced the growth of FHS. With respect to the release characteristics of FHS, the FHS would not completely dissipate and the remaining FHS would accumulate as the F-T cycle increased.

This paper investigated the effect of the changed albedo of colored pavement on the urban temperature. The surface albedo of different conventional and colored pavement slabs was measured in the laboratory. Numerical simulations were conducted to determine the relationship between pavement albedo and the temperatures of pavement and its surrounding environment in the local urban. Results showed that colored porous portland cement concrete (PPCC) slabs have higher albedo values than conventional gray PPCC and black asphalt concrete, but conventional dense portland cement concrete (DPCC) has the highest albedo value owing to its smooth surface. The temperature of colored PPCC (except black PPCC) slabs at 1-cm depth was about 1 degrees C-6 degrees C lower than that of conventional gray PPCC due to the high albedo, and the green PPCC slab had the best cooling effect among all PPCCs. The simulated temperature profiles of the PPCC slab were found to be in good agreement with the laboratory test results. The local urban simulation showed that the colored pavement has a noticeable effect on reducing pavement surface temperature and nearby air temperature. Compared with open-graded friction course, which had an albedo value of 0.058, conventional gray DPCC with an albedo value of 0.32 had a temperature at 0.2 m below the pavement surface that was 0.83 degrees C lower at 3:00 p.m. of a typical summer day.

This paper investigated the effects of phase change materials (PCMs) on temperature field and rutting performance of asphalt concrete (AC) pavement with a focus on PCM types, contents, and locations. To quantify their effects on rut depth accumulation, a pavement finite element (FE) model was constructed with measured material properties and designed structural configuration. The implemented traffic and environmental conditions were obtained from a FE model updating scheme and a heat transfer model with the consideration of traffic speed and the phase change process. Results showed that using polyethylene glycol of 4000 molar mass encapsulated by SiO2 as the PCM to replace 10% of the aggregate in the asphalt top sublayer yielded the best rutting performance; a 14% reduction in the rut depth that was accumulated within one month after pavement construction was predicted for a typical summer case in Texas. This study also revealed that incorporating PCMs into AC does not always lead to pavement rutting performance improvement. This is because (1) the lower thermal conductivity of the PCMs can offset the benefits achieved from the increased heat capacity during phase change, and (2) PCMs will not function if they are added in layers where pavement temperature is not high enough for PCMs to undergo the phase change. Therefore, developing PCMs with higher thermal conductivity together with a judicious selection of PCM types and locations will maximize the effectiveness of the pavement temperature and rutting control.

Poroelastic road surface (PERS) is usually composed of rubber particles, aggregates, and polyurethane. However, the poor bonding strength between rubber granules and polyurethane affects PERS’ durability. This study aimed to improve the durability of PERS with treated rubber using molecular simulation and experimental tests. The cohesive energy density (CED), interaction energy (IE) and shear bonding capacities between two kinds of rubber granules and one-component polyurethane were simulated using molecular dynamics (MD). The hydrophilicity test and Fourier transform infrared (FTIR) spectroscopy test were utilized to demonstrate the formation of oxygen-containing groups on rubber surfaces. The indirect tension (IDT) test and Cantabro test were employed to evaluate the durability of PERS mixtures with treated rubber. The MD simulation results showed that the oxygen-containing groups, including the hydroxyl group (-OH) and the carbonyl group (CO), could improve surface polarity of natural rubber (NR) and styrene-butadiene rubber (SBR) and thereby enhance rubber-polyurethane bonding performance. In particular, hydroxyl groups improved the bonding energy of NR-polyurethane by 59% while the carbonyl groups enhanced the bonding performance of SBR-polyurethane by 20%. The hydrophilicity of the treated rubber granules was effectively improved since new carbonyl groups were introduced on rubber surface. The treatment of rubber with NaOH solution improved the durability of PERS specimens by 8.4% in terms of tensile strength ratio (TSR) and 64.7% in terms of Cantabro abrasion loss. These findings prove the feasibility of designing durable PERS with good functional performance.

基于尾气排放在隧道沥青路面表面形成油膜进而导致路面抗滑性能快速衰减的工程背景,探究了湿度?尾气共同作用下沥青混合料抗滑性能的衰减规律及尾气油膜的形成机理.采用恒温恒湿养护箱及自制尾气处理系统对三种沥青混合料车辙板试件进行了不同湿度?尾气组合作用的模拟,并测试试件摆值用于表征试件的抗滑性能.除此之外,对有水(无水)尾气-沥青界面进行了分子动力学模拟,用以探究尾气油膜形成的微观机理.结果表明,在相对干燥和完全潮湿条件下,随着尾气处理时间的增长三种沥青混合料试件摆值呈现线性下降趋势,完全潮湿条件下尾气处理1h后OGFC混合料抗滑性能衰减幅度较其余两种混合料低近30％,OGFC混合料具有优异的抗滑性,并且在湿度?尾气共同作用下还具有良好的抗滑耐久性.尾气油膜导致的沥青混合料抗滑性能衰减难以自然消散且具有累积效应,是导致沥青混合料抗滑性能快速衰减的主要原因.尾气油膜主要形成在尾气排放后冷却的过程中,水分子主要存在于尾气分子附近0～5?范围内填充尾气分子间空隙,其自身较强的极性能够吸引尾气分子并有助于尾气在沥青分子表面的吸附.

The expansion and contraction of an open-graded friction course(OGFC)with a nominal maximum aggregate size of 13.2 mm(OGFC-13)with three air void contents(AVCs)and six saturation degrees(SDs)exposed to freeze-thaw(FT)cycles were measured using strain gauges.Cantabro tests were conducted on OGFC-13 specimens before and after FT cycles to evaluate the degradation of raveling resistance.The effects of SD,AVC,and the number of FT cycles on the expansion and contraction of OGFC-13 and degradation of raveling resistance were analyzed.Results show that OGFC with low water saturation will contract to stability during the freezing process,whereas fully saturated OGFC will contract first and then expand to be stable.OGFC with a medium saturation experienced three stages,namely,contraction,expansion,and contraction,during the freezing process.For the OGFC with a low SD,the decrease in the void content can effectively reduce the low temperature shrinkage.By contrast,for the OGFC with a high SD,lower void content produces more temperature shrinkage at the beginning of freezing and less expansion at the end of freezing.The decreases in SD and AVC can effectively improve the raveling resistance of OGFCs exposed to FT cycles.

The poroelastic road surface (PERS) mixture with low polyurethane content (PERS-LPC) can reduce the construction cost of PERS pavement, which exhibits promising noise reduction capacity, whereas its mechanical performance needs to be further enhanced for real practice. This study aims to investigate the effectiveness of surface activations of crumb rubber and aggregate to improve the mechanical performance of PERS-LPC. Molecular dynamics (MD) simulations and indoor experiments have been conducted, including the indirect tension (IDT) test implemented on the dry-cured and freeze-thaw PERS-LPC specimens and Cantabro test performed on water-bathed specimens. The results showed that, the oxygen-containing groups, introduced by UV irradiation and KMnO4 soaking, enhanced surface polarity of crumb rubber and rubber-polyurethane bonding strength. The surface activity of basalt aggregate was increased by the inclusion of Portland cement but not by hydrated lime. The IDT strength of the dry-cured PERS-LPC mixture was improved by 10.3-17.5% with activated rubbers and by 35.6% with activated aggregates. The tension strength ratio (TSR) of the freeze-thaw mixture was increased only by 2% with activated rubber but up to 20.8% by the inclusion of 0.5 wt% cement. The Cantabro abrasion loss (CAL) of PERS-LPC specimens was reduced significantly from 20.1% to 11.6% with the soaked rubber and dropped dramatically to 7.9% after inclusion of 0.5 wt% cement. It was recommended to activate crumb rubber with UV irradiation for 24 h and mineral aggregate with 0.5 wt% cement in PERS-LPC mixture in terms of performance enhancement and operation convenience. The findings of this research were expected to support the mix design of an inexpensive and durable PERS-LPC mixture for noise reduction.

为了研究水分-老化耦合作用下沥青胶结料各项性能的演化规律,利用自主研制的"水老化"耦合环境作用模拟装置对OGFC-13混合料进行了3个老化时长,5个接触水量,共15种水分-老化耦合环境作用的模拟.在此基础上,对回收沥青进行了FTIR、旋转黏度和表面张力测试,用以表征沥青的老化程度、力学性能以及黏附性发展规律;采用函数拟合、方差分析等方法,定量分析了水分、老化单独作用及其交互作用对回收沥青各项性能的影响.研究结果表明:水分-老化耦合作用对沥青性能的影响会随着老化时长和接触水量的变化而变化,水分-老化耦合作用下,老化时长是沥青羰基指数变化的决定性因素,沥青的黏度变化及表面张力变化主要受接触水量大小的影响.

为满足无人驾驶车辆快速获取路表构造的需求,建立了基于双侧窄角域摄影的沥青路表三维重构方法.对室内压实混合料和室外路面进行表面三维重构,将平均构造深度计算值与铺砂法、环绕摄影的构造深度值进行比较,验证所建重构方法的正确性.建立了构造标准差、单位面积上峰数、峰高标准差等构造评价新指标,并应用于AC-13、SMA-13和OGFC-13构造分析中.结果表明:双侧窄角域摄影重构方法能快速获取路表的三维点云,重建三维构造;基于该方法的构造深度计算值与铺砂法实测、环绕摄影重构的构造深度值相当,适用于室内压实混合料和室外实际路面;所建立的构造评价指标能从构造分布特征、胎/路接触应力集中度等角度为无人驾驶车辆提供完整的路表构造信息.