PURPOSES : The objective of this study is to evaluate the effect of size and depth of cavities on the pavement failure using the full-scale accelerated pavement testing. METHODS: A full-scale testbed was constructed by installing the artificial cavities at a depth of 0.3 m and 0.7 m from the pavement surface for accelerated pavement testing. The cavities were made of ice with a dimension of 0.5 m*0.5 m*0.3 m, and the thickness of asphalt and base layer were 0.2 m and 0.3 m, respectively. The ground penetrating radar and endoscope testing were conducted to determine the shape and location of cavities. The falling weight deflectometer testing was also performed on the cavity and intact sections to estimate the difference of structural capacity between the two sections. A wheel loading of 80 kN was applied on the pavement section with a speed of 10 km/h in accelerated pavement testing. The permanent deformation was measured periodically at a given number of repetitions. The correlation between the depth and size of cavities and pavement failure was investigated using the accelerated pavement testing results. RESULTS : It is found from FWD testing that the center deflection of cavity section is 10% greater than that of the intact section, indicating the 25% reduction of modulus in subbase layer due to the occurrence of the cavity. The measured permanent deformation of the intact section is approximately 10 mm at 90,000 load repetitions. However, for a cavity section of 0.7 m depth, a permanent deformation of 30 mm was measured at 90,000 load repetitions, which is three times greater than that of the intact section. At cavity section of 0.3 m, the permanent deformation reached up to approximately 90 mm and an elliptical hole occurred at pavement surface after testing. CONCLUSIONS : This study is aimed at determining the pavement failure mechanism due to the occurrence of cavities under the pavement using accelerated pavement testing. In the future, the accelerated pavement testing will be conducted at a pavement section with different depths and sizes of cavities. Test results will be utilized to establish the criteria of risk in road collapse based on the various conditions.

PURPOSES : In this study, noise reduction effect of a two-layer porous asphalt pavement was investigated through site measurement and computer simulation. METHODS: To examine noise reduction effect, a 3 km long quiet pavement was installed by removing previous normal pavement, which had a rather low porosity. The studied site was a high-rise apartment building surrounded by the quiet pavement and Seoul ring road with heavy traffic volume, indicating relatively high background noise. RESULTS: The measurement result before and after installing the quiet pavement showed a noise reduction effect of 4.3 dB(A) at a distance of 7.5 m from the road. After validating the accuracy of simulation using SoundPLAN, the reduction in SPL(sound pressure level) at the facades by the quiet pavement was predicted by considering five different road conditions generating traffic noise from each road or in the combination of the quiet pavement and Seoul ring road. In the case of no noise from Seoul ring road, noise reduction at the facades was 4.2 dB(A) on average for 702 housing units. With background noise from Seoul ring road, however, the average SPL decreased to 2.0 dB(A). Regarding subjective response of noise, the number of housing units with a noise reduction of over 3 dB(A) was 229 out of 706 units (approximately 32%). For 77 housing units, the noise reduction was between 1~3 dB(A), while it was less than 1 dB(A) for 400 housing units. CONCLUSIONS: The overall result indicates that the quiet pavement is useful to reduce noise evenly at low and high floors compared to noise barriers, especially in the urban situation where background noise is low.

PURPOSES: The purpose of this study is to evaluate the effect of the quiet pavement on reducing a barrier height by using a prediction tool called SoundPLAN. METHODS: Firstly, the prediction was carried out to evaluate the difference in the maximum noise level at a building facade between the normal and the quiet pavements without a barrier. After calculating the noise reduction effect by the quiet pavement, a comparable barrier height to obtain the same noise reduction effect with it was predicted according to designable factors including road-building distance(10 m, 20 m, 40 m) and road-barrier distance(5 m, 10 m, 20 m, 30 m). RESULTS: The result showed that within the considered designable factors, the maximum barrier height was 37 m, 52 m, and 55 m to have the same noise reduction effect by the quiet pavement reducing 1 dBA, 3 dBA , and 5 dBA, respectively. It was evaluated that the barrier height increased with the increase of the road-building and road-barrier distances. To simulate the real situation in urban areas and to evaluate the combined effect of the normal/quiet pavement and barrier, the barrier height was fixed as 6 m. It was predicted that the noise level would reduce to as low as 0.2 dBA by the combination of normal pavement and barrier. On the other hand, the combination of the quiet pavement and barrier reduced 1.2 dBA, 3.2 dBA, and 5.2 dBA, respectively, for quiet pavement reducing 1 dBA, 3 dBA, and 5 dBA. CONCLUSIONS: A guideline needs to be suggested to select appropriate noise abatement schemes by considering factors such as the roadbuilding and road-barrier distances.

PURPOSES : This study focuses on the evaluation of interface performance with varying surface texture and tack coat application in an asphalt overlay. METHODS : The evaluation is carried out in two phases: tracking test and interface bond strength test. Using an image processing tool, tracking test is conducted to evaluate the susceptibility of the tack coat material to produce excessive tracking during application. Using the pull-off test method, the bond strength test is performed to determine the ability of the interface layer to resist failure. RESULTS: Results show that the underseal application yields less tracking compared to other applications. However, the bond strength is barely within the minimum acceptable value. On the other hand, RSC-4 produces higher bond strength for all surface types, but the drying time is long, which produces excessive tracking. CONCLUSIONS: While underseal application may be suitable for a trackless condition, the bond strength is less appealing compared to the rest of the tack applications available. RSC-4 demonstrated a high and consistent bond strength performance, but more time is required for drying to avoid excessive tracking. Tack coat application and surface type combination produce varying results. Therefore, these should be considered when selecting suitable future tack coat application options.

PURPOSES : The purpose of this study is to investigate characteristics of crack spacing and crack width and their relationship in continuously reinforced concrete pavement (CRCP) based on the data obtained from long-term field observations. METHODS: The crack spacings and crack widths are measured periodically over 10 years at two different CRCP sections: one with asphalt bond breaker beneath concrete slab, and the other with bonded lean concrete base beneath concrete slab. The effects of steel ratio, type of underlying layer, terminal treatment method, and seasonal temperature change on the crack characteristics are evaluated by analyzing the measured data. RESULTS: The CRCP with lean concrete base shows smaller crack spacings than those of the CRCP with asphalt bond breaker. As the steel ratio increases, both the crack spacing and crack width tend to decrease. The crack width becomes larger as the crack age increases, but once the crack age is over a certain value the crack width tends to converge. When the terminal anchor lug system is not used and the expansion joints are employed at the terminals, the crack spacings and crack widths increase near the terminal sections. The crack spacing and crack width seem to be proportional each other, but not necessarily linearly, and their relationship is more distinguished in the summer when the crack widths become smaller. CONCLUSIONS : The steel ratio, underlying layer type, terminal treatment method, and seasonal temperature change affect the characteristics of cracks and the crack spacing and crack width are related to each other.

PURPOSES : This paper aims to develop a road pavement de-icing system using carbon sheet to replace the older snow de-icing method. Carbon sheet is a light and high-strength metal. Hence, various bodies of research for its applications in many industries have progressed. METHODS : The experiment was conducted in a laboratory. The carbon sheet supplied voltage through a power supply system, and produced heat transfers to the concrete surface. Various factors, such as pavement material, carbon sheet width, penetration depth, and freezingthawing resistance, were considered in the conducted experiments to confirm the heating transfer efficiency of the carbon sheet. RESULTS : The carbon sheet used was a conductor. Therefore, it produced heat if voltage was supplied. The exposed carbon sheet on the atmosphere did not affect the carbon sheet width when it provided constant voltage. However, the sheet showed different heating behaviors by width change when the carbon sheet penetrated into the concrete. Moreover, the freezing-thawing resistance was decreased by the carbon sheet with increasing width. CONCLUSIONS : The experiments confirmed the possibility of developing a road snow melting system using a carbon sheet. The antiicing system using the carbon sheet to replace the traditional anti-icing system has disadvantages of environmental pollution risk and electric leakage. The pavement also improved its toughness resistance. The utilization value will be very high in the future if carbon sheet heat loss can be minimized and durability is improved.

PURPOSES: This study supports the evidence that it is possible to rehabilitate a damaged pavement with a lane closure specifically based on the Gimcheon~Sunsan project. METHODS : The prediction results from the simulation programs were compared with field monitoring, which focused on traffic management planning, congestion (length, time, and passing speed), bypass, and user cost, among others. RESULTS : The research results showed that lane closure application and pavement repair of the aged pavement in Korea were possible, even though the prediction results were minimally different from the field monitoring. The road agency contributes to service life extension of the rehabilitated pavement using this method. CONCLUSIONS: A marginal effect caused by the lane closure was observed on travelling users or vehicles, and the user cost of pavement repair decreased. Therefore, introducing the repair method or rehabilitation in Korea is possible. Information dissemination through various media was properly done to execute the project well. Moreover, the construction area traffic utilized nearby alternative roads. Therefore, improving the repaired pavemen’s service life while ensuring that the pavement management agency can provide a road with comfortable user riding quality was possible.

In a wide spectrum of pavement rehabilitation techniques, the application of thin asphalt overlay on existing concrete pavements have shown its ability to restore the functional capacity of the pavement system as well as maintain structural capacity. Although, prior researches stated that it does not add to the structural capacity of the existing pavement, the insulation generated by the asphalt overlay can affect the behavior of the discontinuities in the continuously reinforced concrete pavement (CRCP) system by reducing the magnitude of its movement. The investigation of crack movement behaviors of the CRCP in Chungbu Expressway was conducted in 2-phases: without overlay and with overlay. Crackmeters were installed at selected crack locations and measurements were collected. In the second phase of the investigation, crackmeters were installed at the concrete layer of the CRCP before a 2-inch asphalt overlay was applied. Results have shown that the crack movements under a thin asphalt overlay have reduced by 80% which indicates an effective insulation of the CRCP.

Recycled tire rubber (RTR) from waste tires has been used in asphalt by the paving industry since the 1960’s. The rubber has been used as asphalt binder modifier and asphalt mixture additive in gap-graded and open-graded asphalt mixtures and surface treatments. The routine use of RTR in pavements has been limited to a few states. While performance is generally good, RTR cost has been high when compared to conventional practices. Local, State, and Federal regulations have also created an increase in the availability of RTR. This has driven a renewed interest in RTR as an asphalt binder modifier and mixture additive – with the goal of providing a long-life, cost competitive, environmentally-responsible pavement system. In 1991, Section §1038(d) of the ISTEA required states to use a minimum amount of crumb rubber from recycled tires in asphalt surfacing placed each year beginning with the 1994 paving season. Although the mandate was lifted in 1995, a significant number of RTR asphalt sections were placed and national research was fostered. Many States discontinued use of RTR after the mandate was lifted. However Agencies such as Florida, Texas, and Rhode Island continued their use of RTR. In 2005, the State of California Public Resource Code Section §42700-42703 legislated the use of RTR. The application of RTR modified asphalt binder has evolved with the development of terminal blended AR binders. This development was driven to reduce the need for asphalt mixture production plant modification (needed to incorporate RTR) and to address some performance concerns. A few RTR pavement failures had been linked to poor quality control with field blending practices. In the Unites States, the predominate use of RTR asphalt pavements has been in warm climates. This has led some to believe that RTR modified materials will not perform well in cold climates. There have been issues with compaction and raveling of mixes in cold climates, but this has typically been a construction issue with unfamiliarity when working with high viscosity binders and trying to pave in cooler climates. In recent years RTR has been in cold climates. One significant property for pavement performance is achieving sufficient compaction on the roadway. Slightly higher binder contents in the RTR modified mixtures may help to achieve sufficient compaction. WMA technologies combined with RTR modified AR mixtures may help reduce production temperatures and also improve workability and compaction. This also could potentially reduce the exposure of workers to fumes that would otherwise be produced in greater concentration with higher mixture temperatures.

Roller-compacted concrete or RCC is a dry concrete that requires compaction in order to reach its final form. Its consistency is usually overlooked due to its inconsistency and lack of subjective nature. To work with this concrete, however, appropriate consistency is required for supporting the compacting machine and minimizing compaction energy. Due to transportation and compaction time, maintaining proper consistency within a period of time is also necessary. Vebe time, a represent parameter of dry concrete consistency, ranged from 30 to 75 seconds is considered appropriate for RCC in pavement application. The purpose of this study is to improve workability of this concrete which consisted of improving its consistency and maintaining it within the working time. It was confirmed that the workable time of a normal RCC is less than one hour. Moreover, it was found that Vebe time drops when water content increases and goes up when sand by aggregate ratio increases. Various admixtures were also employed in this study in order to improve the workability of this concrete. Poly Naphtalene Sulfonate superplasticizer, particularly, was found to be the most effective in term of lowering down Vebe time and maintaining it. With just 0.3% of this admixture, the working time of RCC can be extended up to four hours without affecting its compressive strength.

PURPOSES : Nowadays, cavity phenomena occur increasingly in pavement layers of downtown areas. This leads to an increment in the number of potholes, sinkholes, and other failure on the road. A loss of earth and sand from the pavement plays a key role in the occurrence of cavities, and, hence, a structural-performance evaluation of the pavement is essential. METHODS: The structural performance was evaluated via finite-element analysis using KPRP and KICTPAVE. KPRP was developed in order to formulate a Korean pavement design guide, which is based on a mechanical-empirical pavement design guide (M-EPDG). RESULTS: Installation of the anti-freezing layer yielded a fatigue crack, permanent deformation, and international roughness index (IRI) of 13%, 0.7 cm, and 3.0 m/km, respectively, as determined from the performance analysis conducted via KPRP. These values satisfy the design standards (fatigue crack: 20%, permanent deformation: 1.3 cm, IRI: 3.5 m/km). The results of FEM, using KICTPAVE, are shown in Figures 8~12 and Tables 3~5. CONCLUSIONS: The results of the performance analysis (conducted via KPRP) satisfy the design standards, even if the thickness of the anti-freezing layer is not considered. The corresponding values (i.e., 13%, 0.7 cm, and 3.0 m/km) are obtained for all conditions under which this layer is applied. Furthermore, the stress and strain on the interlayer between the sub-grade and the anti-freezing layer decrease gradually with increasing thickness of the anti-freezing layer. In contrast, the strain on the interlayer between the sub-base and the anti-freezing layer increases gradually with this increase in thickness.

PURPOSES: The national highways and expressways in Korea constitute a total length of 17,951 km. Of this total length of pavement, the asphalt pavement has significantly deteriorated, having been in service for over 10 years. Currently, hot in-place recycling (HIR) is used as the rehabilitation method for the distressed asphalt pavement. The deteriorated pavement becomes over-heated, however, owing to uncontrolled heating capacity during the pre-heating process of HIR in the field. METHODS: In order to determine the appropriate heating method and capacity of the pre-heater at the HIR process, the heating temperature of asphalt pavement is numerically simulated with the finite element software ABAQUS. Furthermore, the heating transfer effects are simulated in order to determine the inner temperature as a function of the heating system (IR and wire). This temperature is ascertained at 300 ℃, 400℃, 500℃, 600℃, 700°℃, and 800℃ from a slab asphalt specimen prepared in the laboratory. The inner temperature of this specimen is measured at the surface and five different depths (1 cm, 2 cm, 3 cm, 4 cm, and 5 cm) by using a data logger. RESULTS: The numerical simulation results of the asphalt pavement heating temperature indicate that this temperature is extremely sensitive to increases in the heating temperature. Moreover, after 10 min of heating, the pavement temperature is 36%~38% and 8%~10% of the target temperature at depths of 25 mm and 50 mm, respectively, from the surface. Therefore, in order to achieve the target temperature at a depth of 50 mm in the slab asphalt specimen, greater heating is required of the IR system compared to that of the gas. CONCLUSIONS : Numerical simulation, via the finite element method, can be readily used to analyze the appropriate heating method and theoretical basis of the HIR method. The IR system would provide the best heating method and capacity of HIR heating processes in the field.

PURPOSES : The field application and performance of continuously reinforced concrete pavement (CRCP), constructed by using the mechanical tube-feeding method, are evaluated in this study. METHODS: The location of the rebar was evaluated by using the MIRA system. The early-age CRCP performance was evaluated via visual survey, in which the crack spacing and crack width were examined. RESULTS: The location of longitudinal reinforcing bars was evaluated via MIRA testing and the results showed that the longitudinal rebars all lie within a given tolerance limit (±2.5 cm) of the target elevation. In addition, owing to the low temperature when the concrete was pured, the crack spacing in the Dae-Gu direction is slightly wider than that of the Gwang-Ju direction. Almost all of the crack spacings lay within the range of 1.0 m~3.0 m. A crack width of <0.3 mm was measured at the pavement surface. However, as revealed by the field survey, the crack spacing was not correlated with the crack width. CONCLUSIONS : In CRCP constructed by using the mechanical tube-feeding method, almost all of the longitudinal reinforcing bars lay within the tolerance limit (2.5 cm) of the target elevation. The concrete-placing temperature affects the crack spacing, owing to variations in the zero-stress temperature. Crack survey results show that there is no correlation between the crack spacing and crack width in CRCP.

PURPOSES: The behavior of a concrete pavement in a tunnel was investigated, based on temperature data obtained from the field and FEM analysis. METHODS: The concrete pavement in a tunnel was evaluated via two methods. First, temperature data was collected in air and inside the concrete pavement both outside and inside the tunnel. Second, FEM analysis was used to evaluate the stress condition associated with the slab thickness, joint spacing, dowel, and rock foundation, based on temperature data from the field. RESULTS : Temperature monitoring revealed that the temperature change in the tunnel was lower and more stable than that outside the tunnel. Furthermore, the temperature difference between the top and bottom of the slab was lower inside the tunnel than outside. FEM analysis showed that, in many cases, the stress in the concrete pavement in the tunnel was lower than that outside the tunnel. CONCLUSIONS : Temperature monitoring and the behavior of the concrete pavement in the tunnel revealed that, from an environmental point of view, the condition in the tunnel is advantageous to that outside the tunnel. The behavior in the tunnel was significantly less extreme, and therefore the concrete pavement in the tunnel could be designed more economically, than that outside the tunnel.

PURPOSES: This paper investigates behavior and performance of concrete pavement in tunnel based on temperature data from field. METHODS : In this study, there are 4 contents to evaluate concrete pavement in tunnel, First, Comparison for distress was conducted at outside, transition, and inside part of tunnel. Secondly, temperature data was collected in air and inside concrete pavement in outside and inside tunnel. Thirdly, FEM analysis was performed to evaluate stress condition, based on temperature data from field. Finally, performance prediction was done with KPRP program. RESULTS: From the distress evaluation, failure of inside tunnel was much less than it of outside tunnel, Temperature change in tunnel was less than out side, and also it was more stable. According to result of FEM analysis, both curling stress status of inside tunnel was lower than it of outside tunnel. Based on KPRP program analysis, performance of inside tunnel was longer than outside. CONCLUSIONS : Through all study about behavior and performance of concrete pavement in tunnel, condition in tunnel has more advantages from environmental and distress point of view. Therefore, performance of inside tunnel was better than outside.

PURPOSES : The objective of this paper is to develop a pavement performance model based on the Bayesian algorithm, and compare the measured and predicted performance data. METHODS : In this paper, several pavement types such as SMA (stone mastic asphalt), PSMA (polymer-modified stone mastic asphalt), PMA (polymer-modified asphalt), SBS (styrene-butadiene-styrene) modified asphalt, and DGA (dense-graded asphalt) are modeled in terms of the performance evaluation of pavement structures, using the Bayesian algorithm. RESULTS : From case studies related to the performance model development, the statistical parameters of the mean value and standard deviation can be obtained through the Bayesian algorithm, using the initial performance data of two different pavement cases. Furthermore, an accurate performance model can be developed, based on the comparison between the measured and predicted performance data. CONCLUSIONS : Based on the results of the case studies, it is concluded that the determined coefficients of the nonlinear performance models can be used to accurately predict the long-term performance behaviors of DGA and modified asphalt concrete pavements. In addition, the developed models were evaluated through comparison studies between the initial measurement and prediction data, as well as between the final measurement and prediction data. In the model development, the initial measured data were used.

PURPOSES: The objective of this paper is to understand the deterioration phenomenon and causes in the pavement of a ramp area. METHODS: Ramp areas need to be sloped because of the centrifugal force, which depends on the vehicle speed and grade of the ramp area. As a result, vertical and horizontal forces are applied on the pavement surface of the ramp area. Furthermore, the horizontal force depends on the vehicle speed and grade of the ramp area. In order to analyze the pavement structure of a ramp area, a multi-layered elastic analysis program was used to evaluate the weakest link of fatigue cracking deterioration, according to the simultaneously applied vertical and horizontal forces. RESULTS : From case studies related to the bonding conditions between the surface and base layer in a ramp area, it was found that the partially bonded cases resulted in a critical potential of fatigue cracking deterioration, in a comparison of 50%, 70%, and fully bonded cases. CONCLUSIONS : According to the results of the case studies, the pavement structure system should be reinforced by upgrading the material or increasing the thickness compared to the general pavement areas, in order to provide a performance life similar to the mainline pavements in the ramp areas.

PURPOSES : The purpose of this study is to develop a method for improving the accuracy of analysis results obtained from a twodimensional (2-D) numerical analysis model of continuously reinforced concrete pavement (CRCP). METHODS: The analysis results from the 2-D numerical model of CRCP are compared with those from more rigorous three-dimensional (3- D) models of CRCP, and the relationships between the results are recognized. In addition, the numerical analysis results are compared with the results obtained from field experiments. By performing these comparisons, the calibration factors used for the 2-D CRCP model are determined. RESULTS : The results from the comparisons between 2-D and 3-D CRCP analyses show that with the 2-D CRCP model, concrete stresses can be overestimated significantly, and crack widths can either be underestimated or overestimated by a slight margin depending on the assumption of plane stress or plane strain. The behaviors of crack width in field measurements are comparable to those obtained from the numerical model of CRCP. CONCLUSIONS: The accuracy of analysis results from the 2-D CRCP model can be improved significantly by applying calibration factors obtained from comparisons with 3-D analyses and field experiments.

PURPOSES : The use of roller-compacted concrete pavement (RCCP) is an environmentally friendly method of construction that utilizes the aggregate interlock effect by means of a hydration reaction and roller compacting, demonstrating a superb structural performance with a relatively small unit water content and unit cement content. However, even if an excellent structural performance was secured through a previous study, the verification research on the environmental load and long-term durability was conducted under unsatisfactory conditions. In order to secure longterm durability, the construction of an appropriate internal air-void structure is required. In this study, a method of improving the long-term durability of RCCP will be suggested by analyzing the internal air-void structure and relevant durability of roller-compacted concrete. METHODS: The method of improving the long-term durability involves measurements of the air content, air voids, and air-spacing factor in RCCP that experiences a change in terms of the kind of air-entraining agent and chemical admixture proportions. This test should be conducted on the basis of test criteria such as ASTM C 457, 672, and KS F 2456. RESULTS : Freezing, thawing, and scaling resistance tests of roller compacted concrete without a chemical admixture showed that it was weak. However, as a result of conducting air entraining (AE) with an AE agent, a large amount of air was distributed with a range of 2~3%, and an air void spacing factor ranging from 200 to 300 ㎛ (close to 250 ㎛) coming from PCA was secured. Accordingly, the freezing and thawing resistance was improved, with a relative dynamic elastic modulus of more than 80%, and the scaling resistance was improved under the appropriate AE agent content rate. CONCLUSIONS: The long-term durability of RCCP has a direct relationship with the air-void spacing factor, and it can be secured only by ensuring the air void spacing factor through air entraining with the inclusion of an AE agent.

PURPOSES: Reflection cracking has been one of the major causes of distress when asphalt pavement is laid on top of concrete pavement. This study evaluated the reflection cracking resistance of asphalt mixtures reinforced with asphalt embedded glass fiber and carbon fiber using a Texas Transportation Institute (TTI) overlay tester. METHODS : Different asphalt mixtures such as polymer-modified mastic asphalt (PSMA) and a dense graded asphalt mixture were reinforced with asphalt-embedded carbon fiber and glass fiber. For comparison purposes, two PSMA asphalt mixtures and one dense graded asphalt mixture were evaluated without fiber reinforcement. Two different overlay test modes, the repeated overlay test (R-OT) and monotonic overlay test (M-OT), were used to evaluate the reflection cracking resistance of asphalt mixtures at 0 ℃. In the R-OT test, the number of repeated load when the specimen failed was obtained. In the M-OT test, the tensile strength at the peak load and tensile strain were obtained. RESULTS : As expected, the fiber-reinforced asphalt mixture showed a higher reflection cracking resistance than the conventional nonreinforced asphalt mixtures based on the R-OT test and M-OT test. The dense graded asphalt mixture showed the least reflection cracking resistance and less resistance than the PSMA. CONCLUSIONS: The TTI overlay tester could be used to differentiate the reflection cracking resistance values of asphalt mixtures. Based on the R-OT and M-OT results, the carbon-fiber-reinforced asphalt mixture showed the highest reflection cracking resistance among the nonreinforced asphalt mixtures and glass-fiber-reinforced asphalt mixture.