Asphalt Materials Research Articles

Comparative cracking resistance‐cost study for the hot mix asphalt (HMA) mixtures made of natural and recycled asphaltic materials

AbstractCracking performance of control and RAPed hot mix asphalt (HMA) mixtures was studied under low and medium temperatures. The effects of recycled asphalt pavement (RAP) content (0 and 50%), compaction method, and temperature (−20, 0 and +20°C) on KIf and KIIf were investigated. Cracking resistances of both modes showed similar trends. The fracture toughness of RAPed mixture at +20°C was higher than the control mixture. However, at −20°C, KIf and KIIf obtained from the RAPed mixture were about 22% lower than control mixture. A cost analysis was performed to compare the manufacturing costs of both mixtures. Accordingly, the cost of HMA mixture containing 50% RAP was 26% less than the control mixture. The proposed life‐cost index in the RAPed mixture was 10, 25, and 100% greater than the control mixture at −20, 0, and +20°C, respectively. Temperature and RAP content had the most important impacts on fracture toughness and cost, respectively.

From the material behaviour to the thermo-mechanical long-term response of asphalt pavements and the alteration of surface drainage due to rutting: a sensitivity study

ABSTRACT In this contribution, a simulation chain for the thermo-mechanical and hydromechanical analysis (surface drainage) of a pavement structure during its whole service life is applied to a typical asphalt pavement (Bk100) used for motorways in Germany. Transient load signals for each tyre position of a truck-trailer combination (vehicle) are generated from a multibody analysis of the vehicle driving on a motorway with rough pavement surface. Material model parameters are derived from experimental identification tests of asphalt materials. The model parameters are used together with a continuum-mechanical description of the asphalt material representing the thermo-mechanical material behaviour at the material scale. The material response of the pavement layers is integrated on the structural scale by using the finite element method (FEM) in combination with an arbitrary Lagrangian-Eulerian (ALE) formulation and equivalent tyre loads of a representative, finite element (FE) discretised truck tyre rolling on an FE discretised pavement section. Different scenarios of rut formation are computed by varying different influence factors (climate temperature, vertical tyre force, type of asphalt material of the surface layers etc.). During the subsequent hydromechanical analysis of the pavement, the simulated deformed geometry of the pavement surface is used to numerically compute surface drainage characteristics.

Stiffening effects of LFS slags reused as filler in asphalt mixtures

Nowadays, the use of Ladle Furnace Steel (LFS) is spreading in the field of asphalt pavements. LFS are generally used as filler in Hot Mix Asphalt (HMA). The main purpose of this study is to analyse and understand the role of LFS characteristics on the possible stiffening effects of asphalt materials. Different characteristics of LFSs, such as particle size distribution, specific surface area (SSA), chemical and mineralogical properties were evaluated in addition to the performance of HMAs on different scales (mastic and HMA). One type of LFS, one standard limestone and their blends were mixed with two different asphalt binders, one pure and one 3.5% Styrene–Butadiene–Styrene (SBS) cross-linked modified. The results showed no significant correlations between the physical properties of the LFS and the performance levels of the HMAs, but it was pointed out that the LFS content in the filler blend should not exceed 30%.

The Impact Of Asphalt Material And Soil Salinity On Crop Growth Of Sunflower

The sunflower represents a significant economic annual plant (oilproducing and edible). Even though the sunflower is categorized as one of the most salt-tolerant plant types and is treated as a significant plant in saline soil reclamation, the rate of its photosynthetic and growth are adversely influenced by high levels of salt in the soil, significantly when the groundwater level rises on the soil surface, which in turn causes the raising of soil salinity. Therefore, there is a critical need to control salt accumulation to increase sunflower crop yields. An evaluation of the impact of asphalt material, soil salinity, groundwater table depth, and soluble ions on the growth of sunflower crops is presented in this paper. Several treatments were used in this study: asphalt material, bitumen material, and controlling treatment. The experiments were conducted, calibrated, and validated during the season of spring 2019. The results show a considerable reduction in soil salinity and groundwater table depth regarding the asphalt material control aspect, thus increasing the growth properties of the sunflower crops. Keywords: Growth of Sunflower, Asphalt and Bitumen Materials, Soil Salinity, Soluble Ions, Groundwater Table Depth.

Use of digital technology to improve the way asphalt roads are constructed

Digital technology has the potential to improve the way asphalt roads are constructed and maintained. The application of technologies, such as remote monitoring and telemetry, are being used to improve the quality of asphalt materials during the construction phase. Based on real-time data, the movement and arrival of delivery vehicles can be monitored and material temperatures can be recorded at each stage of the paving process. Similarly, roller compactor passes can be mapped to show the number of passes, compaction temperature and area of mat covered. Importantly, the technology has the capacity to create a safer working environment for road workers. This paper describes a study that builds on previous research, with the aim of developing notes for guidance and compliance requirements for electronic data monitoring. A series of criteria are proposed to approve the level of compaction based on electronic data. The latter includes the adoption of a similar approach to that being used in the United States, although certain aspects have been adapted for the type of materials and equipment available in Scotland. It is intended that the compliance requirements will be trialled on forthcoming paving schemes to determine their effectiveness and whether further amendments are required.

Microscopic R-curve simulation study of asphalt material fracture

Cracks can significantly influence the service life of an asphalt pavement. To study the microcracking behavior of asphalt materials, this paper utilized molecular dynamics simulation methods to simulate the tensile fracture process of asphalt materials at the microscopic level and described the fracture behavior using R-curve. Two experimental factors, temperature and loading rate, were selected to simulate the tensile fracture of virgin asphalt binder, aged asphalt binder, and SBS modified asphalt binder, and Microeconomic R-curve were constructed based on the fracture displacement and cumulative fracture energy of asphalt materials. Meanwhile, fracture energy, cohesive energy, and energy rate were used to evaluate the fracture behavior of asphalt materials. The results indicated that the micro-R curve simulated by molecular dynamics can well describe the tensile fracture behavior of asphalt. Among the fracture indicators, fracture energy and energy rate were significantly affected by the type of asphalt, while cohesive energy was significantly affected by the loading rate.

Influences of induced heating-healing on fracture properties and life extension of asphalt mixtures: Experimental investigations

In recent years, researchers have concentrated on identifying the effectiveness of induced healing techniques and increasing the healing capacity of asphalt materials. However, the impact of the induced healing method on extending pavement life or the behavior of the pavement in terms of cracking progression has not been evaluated. The main objective of this study is to develop a methodology to evaluate the impact of induced healing on fracture characteristics and life extension of asphalt mixtures. Semi-circular bending (SCB) tests were conducted at both 25 °C and −20 °C. From the SCB test results, fracture-related parameters such as peak load, critical stress intensity factor, strain energy, J-integral, fracture energy, and stiffness were determined. The SCB tests were carried out under cyclic cracking-healing scenarios to assess the effectiveness of the healing process. To quantify the healing efficiency, fracture-related parameters and corresponding healing indices (HI) were measured at each damage cycle. Additionally, service life extensions were calculated based on the analysis of fatigue and thermal cracking resistance. Finally, the HI obtained through other fracture-related parameters were used as a response factor to evaluate the statistical significance of each fracture parameter. The results show that for unaged asphalt mixtures, service life extensions for fatigue and thermal cracking resistance were 3.61 and 3.46 times the initial pavement life, respectively. In contrast, for specimens that experienced 20 years of aging after construction, the corresponding values were 1.50 and 2.23. This suggests that while increasing levels of aging reduce the effectiveness of the induced healing process, the pavement life can still be extended by using the induced healing method. Furthermore, a significant variation was observed in the HI obtained from different fracture-related parameters for asphalt mixtures at different aging levels. This suggests that using the ultimate strength of specimens to determine HI may present conservative results for aged asphalt mixtures since it does not explain the cracking features of the asphalt mixture at intermediate temperatures. The proposed fracture-based method can represent the interactions of cracking and time-dependent behaviors of materials, allowing for the combined effects of the healing process on fatigue and thermal fatigue life extensions to be addressed.

Algorithm Based on the Mixing Ratio of Road Asphalt Materials: from the Auxiliary Perspective of Computer Vision Image Recognition

Algorithm Based on the Mixing Ratio of Road Asphalt Materials: from the Auxiliary Perspective of Computer Vision Image Recognition

Development and Mechanism Analysis of High Temperature Resistant Nanocomposite Modified Asphalt

With the intensification of global warming, continuous extreme high temperature weather occurs frequently, and asphalt materials are prone to softening under continuous high temperature conditions, which can easily cause traffic accidents. Therefore, it is necessary to develop a high-temperature resistant modified asphalt. This study focuses on the research and development of high-temperature resistant nanocomposite modified asphalt under sustained extreme high temperature weather conditions, selects nanocomposite modification schemes, conducts aging, dynamic shear creep, bending small beam, and segregation tests on nanocomposite modified asphalt, comprehensively analyzes the aging resistance, segregation resistance, and high and low temperature performance of nanocomposite modified asphalt, and analyzes the mechanism of nanocomposite modified asphalt from the perspective of molecular dynamics. The research results indicate that the nano/polymer composite modification scheme for sustained extreme high temperature areas is: 3% ZnO+0.5% TiO2+3.5% SBS; The aging resistance and high temperature resistance of nanocomposite modified asphalt are obviously better than that of base asphalt; At a temperature of 413K (160℃), a more stable structure can be formed between asphalt and SBS. At a temperature of around 140℃, each interaction can reach its maximum value, and the modification effect is good.

Investigating the effect of using recycled waste concrete powder (RWCP) on the performance of thin layer surface treatment: Microsurfacing

Considering the importance of roads and highways in creating communication between different areas, and the issue of repair, maintenance and management of roads has always been among the main concerns of the countries. Microsurfacing is among the best methods for the preventive maintenance of roads. On the other hand, in the present age, production of considerable amounts of construction waste (CW) has turned into a major environmental issue. Thus, the use of recyclable CW in pavements could help with the preservation of non-renewable materials and at the same time reduce environmental problems. The present research attempts to implement recycled waste concrete powder (RWCP) in the mix design of thin layer surface treatment (microsurfacing) to evaluate its performance. In this respect, first the chemical and physical characteristics of the used materials in asphalt were investigated. Next, for evaluating the microsurfacing mixtures use was made of five different microsurfacing mixtures containing 0, 25, 50, 75, and 100% RWCP filler. Assessment of RWCP containing microsurfacing mixtures was done by performing the wet cohesion test, wet track abrasion test (WTAT), loaded wheel-sand adhesion test, and loaded wheel-displacement test according to ISSA A143 Guideline. Then using the FTIR, XRF, and FESEM-EDS tests, the structure, chemical bond, and functional groups, constituting components, and shape and surface of the grains were investigated, respectively. The results revealed that RWCP due to containing large amounts of CaO and SiO2, also having a rough surface compared to that of the natural filler could improve the microsurfacing performance. For example per 9% bitumen, the mixture containing 75% RWCP causes an increase of cohesion at 30 and 60 min durations by 23.4 and 22.7%, respectively. Also, it improves resistance against abrasion by 45%, reduction of mixture bleeding by 18%, and increases resistance against vertical and lateral displacements by 20 and 16%. In addition, considering the analysis of variance (ANOVA) results, all the three factors i.e. bitumen, RWCP filler, and interaction of materials were effective on the microsurfacing performance.

Microscopic and rheologic characterization of third generation self-repairing microcapsule modified asphalt

The feasibility and potential application of microencapsulated rejuvenator for self-healing of asphalt materials has been of great interest for the past decade, but the strategy of repairing uncracked aged asphalt remains a major challenge. Herein, a magnetically responsive controlled release microcapsule with a “honeycomb” structure was developed. A new microscopic experimental sample preparation method was developed using optical inverse bright-, darkfield and fluorescence microscopy (OIM) to observe the microstructure of microcapsules and asphalt. Image J software was applied to quantitatively analyze the area ratio of microcapsules and the dimensional characteristics of the bee structure. DSR tests were performed to evaluate the effects of microcapsules on the complex modulus and phase angle of asphalt, as well as the rheological properties under low temperature. The results showed that the microcapsules maintained the structural integrity in the asphalt with large errors in their area statistics, and the results of the high microcapsule admixture samples were closer to the true values. Microcapsules have almost no effect on the basic rheological properties of asphalt, reflecting the fact that the microcapsules survive after high temperature mechanical mixing with asphalt.

Thermodynamics of healing of asphalt binders with free energy

Inspired by self-healing attributes, one of the key topics in the field of pavement engineering is changing the way that asphalt materials behave for prolonged service life and environmental savings. Extensive experimental approaches, models and technologies have been developed to characterize the evolution of healing influenced by internal and external factors. The purpose of this study is to explore the local kinetics of asphalt binders that energetically favor autonomous self-healing as well as its mechanism using free energy method. With consideration of driving forces including internal stress and interfacial forces of attraction (or surface energy) responsible for energy redistribution during the rest period, the healing of an asphalt binder was first modeled as a function of thermodynamic parameters. New healing indexes were then defined by the total free energy change for healing (ΔGH) and fast-rate response ratio (RH) of initial healing in duration to the total rest time. Thirdly, a fatigue-healing test was performed on #70 asphalt binder and SBS-modified asphalt binder to examine the potential and reactivity of healing affected by different damage levels. Finally, the effectiveness of proposed thermodynamic healing indexes in describing healing ability was discussed by considering their relations with properties measured by mechanical analysis. Results show that more negative ΔGH indicates a greater tendency to spontaneous healing while less negative ΔGH suggests a poor healing potential as crack propagates to a certain length. In contrast to #70 asphalt binder, SBS-modified asphalt binder exhibits a superior healing potential on a shorter crack length scale. RH gradually increases with the increase of crack length for both #70 asphalt binder and SBS-modified asphalt binder, implying limited mobility of molecules. By contrast with mechanistic healing indexes assessing properties before and after healing (i.e. the degree of healing), the thermodynamic healing indexes provide a new vision regarding healing potential, which reveals the true ability of a material to autonomously repair damaged areas.

Evaluation of the Suitability of Sulfur Springs Water for Vital Uses by Studying the Physical, Chemical Properties of Some Sulfur Springs Water in the City of Hit

By studying some of the physical and chemical properties of the water of sulfur springs and identifying the nature of that water and the concentration of elements and ions in it and the percentage of salts, and by looking at the Iraqi environmental legislation and the World Health Organization (WHO), we find that the water of the studied springs is unfit for human and animal consumption, because of the concentration of dissolved salts in it, which Exceeding the general allowable rate, in addition to the high concentration of dissolved ions that lead to a change in the properties of that water. It can also be confirmed on the field that the water of those springs is rich in hydrogen sulfide gas (H2S), which is formed as a result of the oxidation of organic substances and the reduction of sulfate ions. In addition, most of the springs of the study area are characterized by the mixing of their water with oil derivatives, adding a state of pollution to that water, which increased the unfitness of that water for drinking purposes. Liquid petroleum (consisting of a complex mixture of different compounds, some of which are volatile or light, and some are heavy such as asphalt materials and bitumen), and natural gas such as methane, ethane, propane, and butane (Al-Jumaili and Ahmed; 2018). These factors and pollutants combined made that water unfit for drinking or human consumption. According to the classification of the American salinity laboratory for the year 1954, and the classification of the FAO for the year 1992, it is considered suitable water for irrigation purposes and watering field. In addition to the validity of spring water for industrial purposes, and its use for therapeutic purposes and hospitalization due to its richness in salts, elements and ions.

Preparation of the composite asphalt material and its performance in road rehabilitation

Asphalt materials have a very wide range of applications in roads, but with the increase of traffic pressure and the intensification of cracking and rutting in traditional asphalt pavements, there is an urgent need to further improve the performance of asphalt materials. In this paper, composite asphalt materials containing 10%, 20%, and 30% trinidad lake asphalt (TLA) and 0%, 2%, 3%, and 4% styrene-butadiene rubber (SBR) were prepared. Their basic properties and the properties of the mixes used for road rehabilitation were analyzed. It was found that the addition of TLA and SBR caused a decrease in the penetration degree of the material, but significantly increased the softening point of the material, TLA was detrimental to the ductility of the material, and SBR could improve the ductility. From the analysis of the performance of road rehabilitation mixes, the comprehensive performance of 20% TLA+3% SBR was good, its dynamic stability reached 3,712.66 times/mm, its water stability was also good, and its stiffness modulus was 3,332.64 MPa. The results prove the improvement of TLA and SBR for asphalt performance, and this method can be applied in practical projects.

Pemanfaatan Recycling Asphalt untuk Lapisan AC-WC dengan Penambahan Material Bottom Ash pada Perkerasan Lentur

Increasing road construction by adding a thick layer of asphalt on flexible pavement can cause problems, where the more viscous the asphalt layer, the higher the road will be than the houses. In addition, limited natural resources and large-scale use can damage the environmental system and make raw materials increasingly scarce, and their prices continue to increase. This research aims to show that recycled asphalt and bottom ash materials can be reused for flexible pavements. Researchers used experimental methods in the laboratory by testing using the Marshall Test. The results of this study indicate that the asphalt resistance based on the compressive strength of the asphalt mixture of recycled materials and the combination of recycled materials and bottom ash of 10% and 15% so that the values of VMA, VFA, Stability, Meltability, and MQ values ​​obtained from the Marshall Test according to with the General Specifications of Highways of the Ministry of Public Works. It was obtained from the provisions of the physical and mechanical test results of Bottom Ash sourced from the Petra UK Road Materials Laboratory Research with the bottom ash parameter passing the sieve of 18.2%. From the results of all asphalt tests, it is known that the addition of bottom ash to asphalt recycling where the extracted material from recycled asphalt (recycled) both asphalt and the aggregate material itself cannot be reused for flexible pavement layers. This is because the condition of asphalt recycling is old, and the strength of the material itself is weak, so it cannot last long if it is reused.
 
 

Investigation of 6PPD-Quinone in Rubberized Asphalt Concrete Mixtures.

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD)-quinone (6PPD-Q), a transformation byproduct of 6PPD used in tires as an antiozonant and antioxidant, was recently discovered as the chemical primarily responsible for the acute lethal toxicity of urban storm runoff to coho salmon. The asphalt concrete (AC) surface layer is the primary medium to contact 6PPD-Q immediately upon its release from tires, and the addition of recycled tire rubber (RTR) to the asphalt binder and mixture is a widely accepted practice in asphalt production. Therefore, it is urgent to understand the fate of 6PPD-Q at the asphalt concrete surface layer-water interface. This study analyzed the sorption and desorption of 6PPD-Q by compacted and crushed loose (loose particles, ∼5 mm) rubberized asphalt mixtures and their mobilization from compacted asphalt mixtures during simulated rainfall events. It should be noted that the crushed loose asphalt mixtures demonstrated the physicochemical properties of the asphalt materials, while the compacted asphalt mixtures represent in-service AC layers. Sorption of 6PPD-Q by crushed loose and compacted asphalt mixtures reached equilibrium within 12 days, with a sorption coefficient of 151.57-257.51 L/kg for compacted asphalt mixtures. Within 12 days, desorption of 6PPD-Q from crushed loose and compacted rubberized asphalt mixtures (20 g particles/L) to the double deionized (DDI) water and synthetic stormwater was 0.01-0.09 and 0.025-0.05 μg/L, respectively. Through the rainfall simulation experiments, 0.0015-0.0049 μg/L 6PPD-Q was detected in the runoff water, much lower than the lethal concentration (LC50) of 6PPD-Q of 0.095 μg/L and 308.67 μg/L for coho salmon and zebrafish larvae. Our results indicate that, while the release of 6PPD-Q from compacted rubberized asphalt mixtures is minor, the mixtures can serve as sorbents for tire-derived 6PPD-Q and retain this emerging contaminant.

Effect of heating history on the emission of volatile organic compounds from asphalt materials

Asphalt binders release hazardous fumes during high-temperature heating that severely endanger human health and pollute the environment. In this study, a volatile organic compound (VOC) generation and detection device comprising a portable VOC detector was developed, and two heating modes (intermittent and continuous heating) were established to explore the influence of heating history on the VOC emission behavior of five asphalt samples. The changes in the VOC species and content, as determined by the heating history, were analyzed via gas chromatography–mass spectrometry (GC–MS). Finally, the key factors affecting the emission of VOCs from asphalt are discussed based on the four components of asphalt materials. The results indicated that the emission of VOCs from asphalt materials under intermittent heating conditions decreased significantly with increasing heating history (significantly fewer VOCs, including 13 common components such as alkanes, benzenes, and hydrocarbon derivatives, were emitted under this condition than under continuous heating conditions at the same temperature point). Compared with continuous heating, intermittent heating is more conducive for studying asphalt VOCs. Under intermittent heating, different asphalt materials exhibited similar VOC emission curves; the VOCs were mainly emitted during the first two heating stages (200 and 180 °C, respectively). Thus, it can be deduced that asphalt VOC emissions were induced by the synchronized actions of the four components of asphalt materials. Therefore, different components can contribute to the emission of several VOCs of the same composition. The heavy and light components mainly facilitate the emission of common components with carbon atomic numbers <18 and > 18, respectively.

Improvements on the analysis methods of asphalt fumes generated in asphalt production and construction

Asphalt fumes are generated when producing and processing asphalt materials, and polycyclic aromatic hydrocarbons (PAHs) are commonly used as indicators to evaluate the hazardous potentials of asphalt fumes. However, the quantitative analysis of PAHs in asphalt fumes remains a challenge. Particularly, the influences of matrix compounds in asphalt fumes on PAH quantification have not been evaluated, even though matrix effect may lead to biased results. To address such a research gap, this study (1) examined the matrix effect in analyzing PAHs in asphalt fumes, (2) evaluated the effectiveness of clean-up methods, and (3) assessed the effectiveness of different methods for matrix effect compensation. Asphalt fumes from seven asphalt materials or conditions were collected and analyzed. Four clean-up methods were evaluated for their influences on PAH identification and matrix effect mitigation. Two approaches were experimented for matrix effect compensation. This study found an obvious matrix effect in the quantitative analysis of PAHs in asphalt fumes. None of the clean-up methods can effectively remove the matrix effect, but both the standard addition calibration (SAC) method and the internal standard calibration (ISC) method can compensate such effect. The findings are expected to assist in accurate quantification and evaluation of PAHs in asphalt fumes.

Microwave Sensitivity Enhanced Asphalt Mastic with Magnetite Powder and Its Performance after Microwave Heating

Microwave heating technology is a promising method for asphalt pavement maintenance and de-icing; however, it requires the material to have a good microwave-absorbing ability and can also result in asphalt aging. It is therefore important to develop microwave-sensitive materials used for asphalt pavement maintenance and study the effects of microwave heating on asphalt aging. This study evaluates the electromagnetic characteristics of limestone powder and magnetite powder and explores the influence of microwave heating on the high-temperature rheological and fatigue properties of microwave sensitivity enhanced asphalt mastic with magnetite powder. A vector network analyzer was used to measure the electromagnetic characteristics of limestone powder and magnetite powder. The magnetite filler asphalt mastics were prepared and subjected to microwave heating for 1 h, 2 h, 3 h, and 4 h. Temperature sweep tests, frequency sweep tests, and linear amplitude sweep (LAS) tests were conducted for magnetite filler asphalt mastics before and after microwave heating. LAS experimental results were analyzed based on viscoelastic continuum damage (VECD) theory. The results show that magnetite powders have better electric field energy storage ability, higher dielectric loss and magnetic loss, and better microwave heating efficiency. The complex shear modulus (G*) and rutting factor (G* × (sin δ)−1) rapidly decrease with the increase in temperature, indicating that the mastics’ ability to resist deformation decreases sharply. The longer the microwave heating time for magnetite filler asphalt mastics, the faster the high-temperature rheological properties decreased as the temperature rose. The fatigue life of magnetite filler asphalt mastics significantly decreases with the increase in strain and microwave heating time. It is suggested to add anti-aging agents into asphalt materials to reduce the aging effect in the process of microwave heating. This study provides a reference for the application of microwave heating technology in asphalt pavement maintenance.

Faster R-CNN Structure for Computer Vision-based Road Pavement Distress Detection

Smart cities can be controlled in all aspects and it is desired to have a structure that is planned to have controllable feedback. Asphalt is generally used as pavement material on roads that provide transportation of vehicles such as cars and buses on the highway. Asphalt material is deformed due to weather conditions, heavy vehicle passage. In the smart city structure, similar deformations should be reported to the relevant unit. In this article, it was tried to determine the deteriorations on the asphalt by selecting the data set obtained from a region with image processing methods and deep learning technique. With the action camera placed in an automobile, a total of 4315 asphalt images with various distortions and without any deterioration were used as dataset. The dataset was classified using a pixel-based Faster Region-based Convolutional Neural Network. Accuracy, precision and sensitivity values were used to make the performance result obtained as a result of classification meaningful. With this proposed method, the average accuracy rate was 93.2%. With these results, an approach that can automatically detect asphalt deterioration in smart city structures has been developed.