Chip Seal Research Articles

Computationally-Affordable Unsupervised Machine Learning Algorithm to Identify the Level of Distress Severity in Pavement Functional Performance

Pavements continually experience various types of distresses that are manifested in the form of defects that will eventually lead to the pavement’s failure. Selection of appropriate preventive maintenance strategies in terms of timing and method retards the large backlog of poor conditions of pavements, therefore improves the system-wide performance in an efficient and cost-beneficial way. However, the pre-treatment functional performance condition of asphalt pavement has a significant impact on the efficacy of preventive maintenance, and to provide years of service, it is necessary to designate an appropriate preventive maintenance method according to the actual functional condition of pavement. This study presents a new unsupervised learning approach for 1) extracting high correlation factors to reduce the dimensionality of feature distress data, and 2) accurately separating attributes that define pavement functional performance into severity levels to effectively assess the practiced preventive maintenance. Three unsupervised machine learning algorithms including feature extract, relevant factor analysis, and cluster analysis were executed. Based on the severity level results of the pre-treated pavement, the effects of four treatment methods (thin overlay, slurry seal, chip seal, and crack seal) were evaluated by a statistical analysis. The preventive maintenance data from the Specific Pavement Studies-3 (SPS-3) experiment of the Long-Term Pavement Performance (LTPP) database are used for the analysis. The results demonstrated that selecting the appropriate maintenance method for the functional performance risk level of the pavement is beneficial in achieving successful treatment results.

Effect of aged material properties on transverse crack performance with two-round field observations

This paper is aimed to validate the trend between thermal-related parameters and field-measured thermal cracking. Field thermal cracking is collected from four projects with twelve pavement sections. The material properties include creep compliance m-value and tensile strength of mixture, and asphalt low-temperature performance grade (PG). A lower value of m-value and tensile strength leads to a higher thermal cracking, while the low-temperature PG has the contrary trend. One or even several material properties cannot fully characterize field thermal cracking for all projects. Then the change of material properties, pavement structures, and climatic conditions are considered in three-dimensional finite element models (FEM). The aging effect of material properties attributes to the increase of thermal stress. The placement of chip seal could greatly reduce the aging rate, and the thicker pavement result in less thermal stress. Both material property and thickness are important design factors for thermal cracking resistance.

The Effect of The Bearing Capacity of Sub-Grade Soil on The Thickness and Cost of The Superstructure of Chip Seals

applied for preventative treatment of an existing road or to overlay low-trafficked roads. The thickness of the superstructure of a chip seal pavement is directly related to the bearing capacity of sub-grade soil. The bearing capacity of soil is represented by Resilient Modulus (MR) for the design of the thickness of layers. This study has focused on the effect of the bearing capacity of sub-grade soil on the thickness and cost of superstructures of chip seals. In addition, linear regression analysis was performed to investigate the relationship between the bearing capacity of the subgrade soil and the thickness of the superstructure. Two-dimensional numerical modeling was performed with the layer thicknesses found according to the resilient modulus. It was indicated that there was a strong correlation between the bearing capacity of sub-grade soil and the thickness of superstructures of chip seals with high R-square values. An increase in the bearing capacity of the subgrade resulted in a decrease in the thickness of the superstructures of the chip seal. So, it has importance in the aspect of economical to select the most proper soil that will be used in the superstructure of chip seals by taking care of the environment and conditions. In addition, Plaxis 2D modeling shows that a double-chip seal has less deformation and better bearing capacity than a single-chip seal.

Noise Performance of Chip Seal Pavements

Increasing numbers of local and state highway agencies are using chip seals for highway pavement maintenance owing to their relatively low cost and simplicity of application. These surfaces can significantly increase both exterior traffic noise levels and interior noise for vehicle occupants. Recent studies included as part of the NCHRP 15-68 Effect Low Noise Rumble Strips Project have quantified these effects using pass-by and interior noise and on-board sound intensity (OBSI) measurements in several states. To minimize the tire–pavement noise generated by chip seals, the California Department of Transportation (Caltrans) has conducted research on different chip seal pavement designs near the City of Bishop, California. Previous measurements of chip seal pavement have indicated an average OBSI level of 106.2 dBA with a range of ±2 dB. The five quietest test sections at Bishop produced an average level of 101.8 dB with a range of ±0.6 dB. In this paper, previous pass-by and interior noise and OBSI measurements are provided along with the comparison of OBSI data to that measured at the Bishop sites. The performance and design information on the Bishop sites are also provided.

Study Effects of Gradation and Material Thermal Property of Chip Seal Aggregates in Roller Concrete Pavement Crack Healing by Image Processing and RMS.

One of the most roller cement concrete pavement failures of pavement is the formation of first cracks. The roughness of its completed surface after the installation has restricted the usage of this pavement. Therefore, engineers increase the quality of service of this pavement by placing a layer of asphalt coating; The primary goal of this study is to evaluate the impact of particle size and type of chip seal aggregates on filling cracks in rolled concrete pavement. Accordingly, rolled concrete samples with chip seal covering were prepared with various aggregates (limestone, steel slag, and copper slag). Then, the influence of temperature on its self-healing ability was tested by putting the samples in the microwave device for cracking improvements. With the aid of Design Expert Software and image processing, the Response Surface Method reviewed the data analysis. Even though due to the study's limitations, a constant mixing design was applied, the results of this study indicate that the amount of crack filling and repair in specimens slag is higher than that of aggregate materials. With the increase of steel and copper slag, 50% of repair and crack repair at 30 °C, the temperature is 27.13% and 28.79%, respectively, and at 60 °C, the temperature is 58.7% and 59.4%, respectively.

Comparison of asphalt emulsion-based chip seal and hot rubber asphalt-based chip seal

The use of asphalt emulsion chip seal and hot rubber chip seal as pavement preservation techniques has been gaining popularity. This study aims to compare the laboratory performance of asphalt emulsion and hot rubber asphalt used in chip seal applications. Interlayer shear strength (ISS) and interlayer tensile strength (ITS) tests were designed to evaluate the bond quality of the chip seal samples prepared for both materials. The sweep test was used to estimate the aggregate loss of the chip seal on the asphalt pavement. The universal testing machines were used to evaluate the deterioration of the ISS and ITS values under cyclic load conditions, while the tensile and shear bond properties of chip seals under wet-freeze conditions were evaluated using freeze-thaw cycles. Results showed while both materials experienced a decline in their ISS and ITS values following repeated cycles of load and freeze-thaw, the hot rubber chip seal demonstrated significantly higher ISS and ITS values than the asphalt emulsion chip seal (48–111% and 36–102%, respectively). Moreover, the hot rubber chip seal exhibited better performance in terms of aggregate retention and cohesive strength. The aggregate gradation would affect the aggregate retention and cohesive strength. Nonetheless, both treatments are deemed acceptable for pavement maintenance. The weak bond between hot rubber asphalt or asphalt emulsion and aggregate could be attributed to cyclic load and freeze-thaw conditions.

Using Construction and Demolition Waste Materials to Develop Chip Seals for Pavements

Construction and demolition waste (CDW) materials account for a considerable part of waste materials throughout the world. As these materials are not usually recycled, reusing them in construction projects is of major significance. In this study, recycled concrete, bricks, and glass were used as 100% aggregates of chip seal, which is a corrective or preventive pavement maintenance method. A cationic rapid setting (CRS-2) bitumen emulsion was also used to prepare the chip seal. Different tests, including the sand patch test, sweep test, British pendulum tester (BPT), interface bond, and Vialit test, were conducted. The results of these tests revealed that all these materials had sufficient aggregate embedment for vehicle speeds of more than 70 km/h, and the number of chips was less than 10%, indicating their good performance. All developed chip seals ranked as high skid resistance pavement at ambient temperature. The chip seals developed with concrete and glass showed the best adhesion with an asphalt pavement surface and an aggregate–bitumen adhesion at very cold and ambient temperatures due to the fact of their chemical compositions. Overall, using concrete aggregates to develop chip seals under different traffic loads is recommended. Finally, these findings can provide a novel approach for recycling CDW materials with low costs.

Evaluation of chip seal mixture design methods using modified Hamburg wheel tracking test and sweep test

The objective of this study was to identify the most effective chip seal design method and chip sizes by conducting a modified Hamburg wheel tracking test and sweep test. Three chip seal design methods, including Austroads, McLeod, and Vietnam methods, were evaluated to design several chip seal mixtures with varying aggregate sizes (e.g., 12.5, 9.5, 4.75, and 2.36 mm) and binder types. To assess the performance of the chip seal mixtures, aggregate loss and bleeding susceptibility were measured. The sweep test was utilized to determine the amount of aggregate loss caused by the sweeping effect, while the modified Hamburg wheel tracking (HWT) test was developed to estimate the aggregate loss caused by the braking effect using a fixed pneumatic rubber tire. Additionally, a modified Hamburg wheel tracking test with a rolling pneumatic rubber tire was used to assess bleeding susceptibility, and the bleeding area was quantified using an image analysis process. The results indicated that the Austroads design method exhibited the lowest aggregate loss compared to the McLeod and Vietnam methods. Moreover, the consistent findings from both the sweep test and modified HWT test demonstrated the feasibility of using the modified HWT test to simulate aggregate loss caused by the braking effect. The bleeding percentage was found to be affected not only by the binder application rate but also by the aggregate size and the number of layers applied. The Austroads and McLeod chip seal mixtures exhibited an approximately 20 % lower bleeding percentage than that of the Vietnam mixtures. Finally, for a single chip seal, a 9.5 mm chip aggregate was determined to be the optimal size, while for a double chip seal, 4.75 mm and 2.36 mm chips were recommended.

Rehabilitation Options and Guidance for Severely Distressed Low-Volume Paved Roads With a Focus on Conversion to Engineered Unpaved Surfaces

A large percentage of low-volume paved rural roads in the United States are in a severely distressed state, primarily owing to delayed maintenance because of limited funding. Road agencies are now faced with decisions on what to do with these roads under constrained budgets. Options include closing selected roads completely if more than one road can be used to access properties; converting the distressed paved road to an engineered unpaved road, pulverizing the existing materials to form a new base and applying a surface treatment (e.g., chip seal); or doing a full-depth recycle, potentially with supplemental aggregates, using bituminous or cementitious recycling agents (choice dependent on the properties of the recycled material) and then applying a surface treatment or thin asphalt overlay. Choice will depend on traffic volume, safety concerns, available materials, and available funds. Regardless of the choice, sound engineering procedures should be followed throughout the conversion or rehabilitation process to ensure that funds are used optimally and that the road provides satisfactory performance over its new design life. This paper provides guidance on converting roads to an engineered unpaved standard.

Developing methods and strategies to reduce the impact of rumble strips (RS) on pavement performance

ABSTRACT Despite numerous research studies inspecting the safety benefits of centreline and shoulder rumble strips (RS) on pavements, there has been limited exploration into the impact on pavement durability due to the installation of RS. The RS milling process creates micro-cracks in the pavement structure that could propagate to macro cracks over time with freeze and thaw, moisture damage, and traffic loading, thereby decreasing the lifespan of the pavements. The primary objective of this study was to develop testing procedures for RS samples as well as analysis methods to determine the impact of potential controlling factors such as permeability and resulting moisture damage; freeze–thaw; the presence of microcracks; surface layer sealants (chip seal); RS size, depth, type, and RS location in relation to the longitudinal construction joint. The flexural beam fatigue test suggests that sinusoidal rumble strips had 38% increased fatigue cracking resistance. Moreover, the sinusoidal rumble strip resulted in 41% improved cracking and structural performance in the Hamburg Wheel Tracking Test (HWTT) tests. Also, the rutting performance of sinusoidal rumble strips was similar to the control section without rumble strips. In addition, 0% moisture infiltration was observed in sinusoidal rumble strip specimens.

Raveling performance of conventional and rubberized chip seal under field and laboratory traffic loading

Raveling, or the loss of surface aggregate, is a major concern in chip seal pavement. Previous studies have used the Standard Sweep, Vialit, and Pennsylvania tests to evaluate raveling, but these tests do not replicate the stresses of rolling vehicle tires on chip seal and have produced inconsistent results. Additionally, these tests mainly evaluate early-stage raveling due to their short curing time. In this study, a small-wheel traffic simulation device (SWTS) was used to apply similar stresses as rolling vehicle tires and produce comparable raveling results. This was confirmed through a 13-month field observation of chip seal, where the laboratory and field data were compared and correlated. Both conventional (mineral aggregate) and eco-friendly rubberized chip seal with 25%, 50%, and 100% crumb rubber as aggregate were tested in the laboratory and field. The effects of different aggregate types, binder application rates, and crumb rubber contents were studied. The results showed that each wheel application by SWTS is equivalent to 2.5 to 3 passenger car passes in the field. It was also found that the majority of macrotexture loss occurred in the first 50,000 passenger car equivalent load. Up to 50% replacement of mineral aggregate with crumb rubber did not significantly affect the raveling resistance but using more than 50% rubber impaired the raveling resistance. Using crumb rubber instead of mineral aggregate also significantly reduced tire wear and microplastic emissions from vehicle tires. Moreover, it was found that Pennsylvania and Vialit tests may not be suitable for assessing aggregate retention under traffic load.

Noise and Pavement Rehabilitation Using Chip Seal Surfaces

In the United States, increasing number of local and state highway agencies are using chip seals for highway pavement rehabilitation due to their relatively low cost and simplicity of application. These surfaces can significantly increase both exterior traffic noise levels and interior noise for vehicle occupants. Recent studies have quantified these effects using pass-by and interior noise and on-board sound intensity (OBSI) measurements. In order to minimize these effects, the California Department of Transportation (Caltrans) has conducted research on different chip seal pavement designs near the City of Bishop, California. Previous measurements of chip seal pavement have indicated an average OBSI level of 106.2 dBA with a range of ±2 dB. The five quietest test sections at Bishop produced an average level of 101.8 dB with a range of ±0.6 dB. In this presentation, the previous pass-by and interior noise and OBSI measurements are provided along with the comparison of OBSI data to that measured at the Bishop sites. The performance and design information on the Bishop sites are also provided.

Revisiting Field Performance of Cold Central-Plant Recycled Test Sections at MnROAD Low-Volume Road

In 2017 four test sections (test sections 133, 233, 135, and 235) containing a cold central-plant recycled (CCPR) layer underneath a surface treatment were constructed on the MnROAD low-volume road (LVR). Two types of CCPR mix designs were constructed: test sections 133 and 235 contained an emulsified asphalt; test sections 135 and 233 contained a foamed asphalt. Each CCPR mix design (foamed asphalt and emulsified asphalt) had two types of wearing surface layers (double chip seal and 1.5 in. HMA [hot-mix asphalt] overlay—thinlay) to create the four test sections. The rest of the pavement structure beneath the newly constructed CCPR was left in place and consistent throughout all four test sections with the remaining granular base over the existing clay subgrade. This paper presents a revisiting of the field performance of the CCPR test sections at the MnROAD LVR. To do this extensive field data was collected over approximately 3 years through visual distress surveys, and ride quality, rutting, and falling-weight deflectometer testing. Field study determined that both CCPR mix designs (foam and emulsion) performed similarly and the thinlay HMA layer outperformed the double chip seal in respect of rutting; but both surfaces are considered valid alternatives for future applications depending on the traffic volumes expected.

Investigating the Laboratory Performance of Crumb-Rubber-Modified and High-Float Polymer-Modified Asphalt Emulsions in Chip Sealing

Chip sealing is a widely popular pavement maintenance treatment because of its low initial cost and convenient construction process. Bleeding, loss of aggregate, reduced skid resistance, and aging have been identified as the most common type of distress that lead to the failure of chip sealing. The objective of this study was to evaluate the laboratory performance of a crumb-rubber-modified asphalt emulsion and a high-float polymer-modified asphalt emulsion in chip sealing and to evaluate the effects of crumb rubber as a modifier as well as its utilization as part of the aggregate stone. To achieve this objective, four types of emulsion were evaluated, namely a crumb-rubber-modified asphalt emulsion (CRS-2TR), a high-float polymer-modified emulsion (CHFRS-2P), a polymer-modified emulsion (CRS-2P), and a conventional unmodified emulsion (CRS-2). Based on the results of the experimental program, it was concluded that the aggregate retention properties of polymer-modified and crumb-rubber emulsions were superior to the unmodified emulsion. In addition, the granite aggregate performed better than the granite–crumb-rubber blends regardless of the type of emulsion used. However, a small percentage of crumb rubber may be used in chip sealing without significantly affecting its performance. According to the rheological and physical test results, CHFRS-2P showed the highest useful temperature interval (92.7), followed by CRS-2P (87.8), CRS-2TR (82.6), and CRS-2 (76.7). Based on Fourier transform infrared spectroscopy and saturate, aromatic, resin, and asphaltene test results, both CRS-2TR and CHFRS-2P showed lower carbonyl indices growth as compared to the other emulsions, indicating superior resistance to aging.

Identification and evaluation of spalling aggregate in chip seals in three dimensions

In the context of the present lack of aggregate spalling identification methods and the imprecise recognition of images of aggregate spalling points owing to aggregate stacking and coverage in the course of chip-seal paving, this paper proposes an aggregate spalling recognition method based on 3-D laser elevation data points in order to improve the recognition accuracy of spalling aggregate in chip seals. In this study, 3-D point elevation data on the surface of a chip seal specimen were fed into the 3-D laser detection equipment, the raw data were smoothed, the super four-point fast and robust matching method was used on the 3-D laser points for registration, and 3-D reconstructions of the chip seal were built based on the laser point after registration, and 3-D reconstructions before and after spalling were overlaid with the different values of the surface elevations before and after spalling. The spalling plane curve was then obtained using contours from the differences in the values of the surface elevation before and after spalling, and the spalling perimeter Ln, spalling area Sn, and spalling volume Vn were then calculated on the basis of the 3-D coordinates of the spalling curve. The results showed that the relative errors of the spalling area measured by the laser method and the OTSU method (an image segmentation algorithm proposed by Otsu (1979)) were #1 3.1% vs 4.0%, #2 4.4% vs 6.4%, #3 3.3% vs 58.2%, respectively, indicating that the bitumen attached to the aggregate and the overlap of plane images of aggregate due to aggregate stacking are the main reasons for the greater errors in the recognition of image method. The relative errors in the spalling perimeter of the three specimens are 12.61%, 1.60%, and 0.94%, the relative errors of spalling area are 3.13%, 4.36%, and 3.31%, and the relative errors of spalling volume are 6.69%, 6.57%, and 8.71%, which are less than the approximately same level 10% indicating that the accuracy and the stability of aggregate spalling recognition based on 3-D laser elevation data is excellent.

Survival analysis to determine the factors affecting the optimum timing of chip seal application

Survival analysis to determine the factors affecting the optimum timing of chip seal application

Testing and evaluation for long-term skid resistance of asphalt pavement composite seal using texture characteristics

As a common means to improve the skid resistance of asphalt pavement, chip seal is widely used for road surface treatment and preventive maintenance. As the aggregate is progressively dislodged under repeated wheel loads, continuous loss of the surface texture characteristics occurs, and its skid resistance increasingly declines. Therefore, it is necessary to further refine the process of chip seal. In addition, in order to scientifically evaluate its performance and accurately predict the deterioration, the relationship between the surface texture characteristics and the skid resistance needs to be quantitatively established. In this paper, a composite seal structure was proposed by applying sand-containing fog seal layer on top of chip seal. Firstly, four seal schemes (i.e., 3–5 mm chip seal, 5–9.5 mm chip seal, 3–5 mm composite seal and 5–9.5 mm composite seal) were designed and loaded by a four-wheel rotary accelerated abrader. Secondly, the skid resistance indexes of each scheme were investigated under different abrasion times using pendulum meter and sand patch method. In this process, the three-dimensional texture characteristic parameters (i.e., Ssk, Spd, Spc, Vmp and Vmc) of the specimen surface were also obtained by laser scanning. Finally, by analyzing the data, the relationship between the seal texture characteristic parameter and the skid resistance index was established, and the decay law prediction model of the skid resistance for four seal schemes was derived. It is found that the pendulum value and texture depth of the seal decreased with the increase of abrasion times, but the composite chip seal can reduce the decreasing rate of skid resistance index. Sq, Spd, Spc and Vmc showed good synergistic decay laws with the British pendulum number (BPN) and mean texture depth (MTD), among which Spc had the best correlation and can be used as an parameter to characterize the skid resistance of the seal. The relationship and decay prediction model established in this paper can be used to characterize the skid resistance of chip seal and predict the decay law of the skid resistance.

Investigation of the effect of using preheated aggregate and modified binder on chip seal adhesion properties

Chip seal constructed on a compacted granular base are widely used in Turkey, South Africa, Australia, New Zealand, England, etc. Especially, a significant portion of 40183 km of Turkey's 67333 km road network consists of chip seal roads. Chip seals are also used for deterioration preventive maintenance purposes for bituminous hot mix asphalt. The performance of the chip seal can be affected by numerous factors before and after construction. The adhesion performance of the aggregate in the chip seal is significantly affected by the traffic volume of the road, its location, climate, the nominal size of the applied aggregates and the construction method, etc. In this study, three types of aggregates and two types of bitumens were used. Also, bitumen samples were modified with Poly Phosphoric Acid (PPA) at three different percent (at 0.5%, 1.0 and 1.5% by weight) so totally eight type bitumen samples were used. The effect of using heated aggregates at four different temperatures (80 oC, 90 oC, 100 oC, 120 oC) on the adhesion performance of chip seal was investigated by Vialit adhesion and Nicholson stripping tests. Besides, a benefit/cost (B/C) analysis of the improvement of adhesion due to heating the aggregates and modifying the bitumen with PPA in the chip seal application was performed. It was understood that the heating of the aggregates and the PPA additive played a healing role on the adhesion. It was concluded that the use of preheated aggregates provides a higher B/C value than the use of PPA additives. The most important reason for this is that the unit cost of the PPA additive is higher than the aggregate heating cost and the adhesion performance is as good as the PPA added bitumen.

Field Performance and Cost-Effectiveness of Chip Seals and Asphalt Concrete Overlays with and without Asphalt Concrete Stripping Damage

The objective of this study was to evaluate the effects of asphalt concrete (AC) stripping damage on the field performance and cost-effectiveness (CE) of chip seals and AC overlays in pavement maintenance and rehabilitation. To achieve this objective, in-service pavement sections were selected from the Louisiana pavement management system (LaPMS) database and the presence of moisture damage was confirmed through the visual inspection of extracted cores. Sections were categorized according to traffic volume and their pavement condition index before treatment (PCI-). Road sections in each group were then divided into two groups as stripped and non-stripped sections. The average deterioration rate (ADR), extension in pavement service life (ΔPSL), average condition improvement over the treatment service life (PI), and CE were compared for stripped and non-stripped sections. Results showed that for chip seal sections, moisture damage negatively affected the performance of the sections with PCI- < 80 and low traffic volumes. For sections with PCI- > 80, similar performance was observed for stripped and non-stripped sections. For AC overlays, moisture-induced damage significantly affected the long-term pavement performance at all traffic levels. On average, moisture-induced damage decreased ΔPSL, PI, and CE of AC overlays by 5 years, 24%, and 0.5%, respectively. Overall, results of the study demonstrated that moisture damage has a significant effect on the performance of chip seal and AC overlay. Therefore, it is critical to identify and repair stripped sections before the maintenance and rehabilitation of in-service pavements to ensure adequate performance and optimum CE.

Traffic and Climate Impacts on Rutting and Thermal Cracking in Flexible and Composite Pavements

The study presented in this paper analyzed four long-term pavement performance (LTPP) test sections located in the states of New York (NY) and California (CA). Two of them are flexible pavement sections, whereas the other two are composite pavement sections. Two levels of analysis—in-state analysis and cross-state analysis—were performed for these pavement sections to determine the impacts of traffic and climate conditions. The performance of the pavement sections was evaluated in respect of thermal cracking and rutting resistance. The in-state analysis focused on comparing the pavement sections located in the same state. The two pavement sections located in CA exhibited insignificant variation in thermal cracking, although one of them had an additional 1.5” (38 mm) dense-graded asphaltic concrete (AC) layer. On the other hand, the additional 1.5” (38 mm) AC layer resulted in a significant reduction in the rutting depth in one pavement section. The in-state analysis of the two pavement sections located in NY revealed that the 0.8” (20.4 mm) chip seal layer had significantly low resistance to thermal cracking and rutting. The cross-state analysis examined pavement sections of comparable structural capacities—two with low structural capacity, and two with high structural capacity. The performance comparison of the two pavement sections with low structural capacity revealed that the chip seal layer exhibited a significantly high rutting depth, i.e., low rutting resistance under high traffic loads in a freezing climate. On the contrary, the two pavement sections with high structural capacity showed relatively high rutting resistance in both warmer and freezing climates. Furthermore, this paper presents the pavement deterioration models for rutting and thermal cracking in the LTPP test sections. These models were developed using multiple linear regression considering the pavement service life (age), traffic load (average annual daily truck traffic, AADTT), and climate impact (freezing index, FI). The deterioration models had coefficients of determination (r2) in the range of 0.82–0.99 and standard errors varying from 0.01 to 9.92, which indicate that the models are reliable.