Advanced Materials Research Vol. 723

Abstract: The determination of appropriate pavement thickness using laboratory determined parameters is one of the key issues facing the road manager. Five different types of asphalt mixes were produced in laboratory to modify pavement performance mixture. The main objective of this study is to evaluate the characterization methods for fatigue performance of asphalt mixes to Western Australia road. In this study, laboratory test for indirect tensile modulus, dynamic creep, wheel tracking and aggregate gradation tests were taken to analyze each asphalt mixtures for a design traffic road. The results and analysis showed that AC20-75 asphalt mix blow is the most effective and efficient in pavement performance than the other asphalt mixes. AC14-75 was the second in rank to strengthen and durability of asphalt pavement. All asphalt mixes in this study can be used to strength and stable the overall stiffness of pavement, and modification rank can be described as AC20-75 Blow > AC14-75 Blow > AC14-50 Blow > AC7-50 Blow > SMA7-50 Blow in this research.

Abstract: By focusing on the result of The Annual National Safe and Accessible Sidewalk Assessment project, this study performed factor analysis between the practical conduct and policy conduct. The study reviewed on previous sidewalk safe and accessible literature reviews; such as elderly population, safe and accessible space and planning design of sidewalk, and factor analysis related researches. From the result of factor analysis, two factors were extracted from the policy aspect and three factors were extracted from the practical conduct. For the two factors that extracted from the policy conduct, it was the Overall Planning Management and Execution and Sidewalk Suitability. For the Overall Planning Management and Execution, its eigenvalue was 4.866 and the explained value reached 54.069; which was the primary influence factor of the policy conduct. As for the three factors that extracted from the practical conduct, it was the Accessibility, Safety Facility Maintenance Condition, and Space Planning. Among the factors, the eigenvalue of Accessibility was 5.179, and explained variance reached 51.786; which was the primary influence factor of the practical conduct. Therefore, it was suggested that for future improvements on the pedestrian environment, governmental agencies should strengthen on relevant sidewalk policies in order to regulate pedestrian safe and accessible space. It should accord the legal policies to execute on the overall improvement and development plan of the practical conduct. Other than that, in the process of practical assessment, it should have efficient and active action and planning on the safety and space aspects.

Abstract: The prevalence rate of sidewalk was currently one of an important index to assess the development on various international countries. However, according to the result of The Annual National Safe and Accessible Sidewalk Assessment project on urban roads that conducted in recent year by the Construction and Planning Agency, Ministry of Interior; the suitability of sidewalk setting still has many issues for improvement. This study focused on the current condition of urban sidewalk environment, and conduct analysis by utilizing the Structural Equation Model (SEM) to explore important variables that influenced on the suitability of sidewalk. According to the analyzed result of the SEM, the width and clearance height of sidewalk were important factors that influenced on suitability of overall sidewalk. Therefore, from the result, improvement on sidewalk should improve the width and clearance height in priority.

Abstract: This paper investigates the effect of tire width to tire-pavement noise. A tire-pavement noise numerical model in the near field has been developed using the three-dimensional finite-element method, and performed in the standard FEM code package ADINA. The model is composed of two main components: a rolling tire pavement interaction model and a sound propagation model. The tire width studied ranged from 180 to 210 mm. The computer simulation model was calibrated and validated using experimental results made available from past research. From the simulation results, it was found that tire width has a noticeable effect on tire-pavement noise. In particular, it was found that tires with wider base were found to produce higher noise levels.

Abstract: Transverse rumble strips were commonly installed on approaches to intersections, toll plazas, and horizontal curves. The main function is to alert drivers by creating noise and vibration. This TRS has been demonstrated to be effective in reducing traffic accident due to sleeping. However, there are some disadvantages in its utilization, such as traffic noise produced by TRS. The objective of this study was to quantify the level of traffic noise; to verify the effects of speed and TRS shapes. Two types of vehicles [sedan and minivan] were driven over four different patterns of TRS and over cement concrete pavement at four different speeds. Researchers measured the produce noise at 7.5m distance with 1.2 m height from center of the vehicle lane at each test section. Results indicate that vehicle type, speed, TRS shape affects created traffic noise. The sound level of Type A was statistically highest among others.

Abstract: AASHTO (1993) predicts the backcalculated subgrade resilient modulus on an existing flexible pavement as a function of load applied, surface deflection at a ratio of radial distance to 0.7 of radius of stress bulb at the subgrade pavement interface least one. This paper reports the investigation on the accuracy of the predicted subgrade resilient modulus. From the investigation, the ratio of radial distance at least 1.5 is a better limit. The prediction is improved after an adjustment factor. For thick pavement structures, adjustment factors depends on the pavement structure, it is greater than 1.2. For other cases, with the ratio of radial distance greater than 4.0 the adjustment factor is more stable in a range of 1.06 to 1.10. For the ratio of radial distance in a range of 1.5 to 4 which is more practical for daily routine evaluation, the adjustment factor is in a range of 1.06 to 1.20, and the proposed adjustment factor to be used for pavement evaluation is 1.15.

Abstract: In most USA asphalt construction projects the goal of compacting a hot-mix asphalt (HMA) layer is to achieve the optimum density which is 92% of the maximum specific gravity (G_mm) of the asphalt mixture. However, this level of density is not always achieved. This paper evaluates the effect of field compaction deficiencies on the HMA durability through laboratory testing. HMA samples were collected from construction sites in the United States. A series of laboratory tests were conducted to compare the performance of HMA mixtures at their actual in-place density as well as the desired density of 92% of G_mm. The statistical analysis on the results showed that the performance of the pavements could significantly improve by eliminating the deficiencies in their in-place densities. Moreover, the compactibility of the mixtures was investigated using the compaction data from the Superpave gyratory compactor. Compaction characteristics of the mixtures were compared to a control mixture, and the results showed that the shortage in the binder content of the mixtures could be a major factor which may have caused the density deficiencies. Furthermore, the effect of higher-than-optimum binder content was evaluated on the compactibility of the control mixture.

Abstract: In this paper, rolling thin film oven is used to heat No.70 road asphalt to simulate asphalt aging. Six aging time tests of 0min, 40min, 85min, 180min, 240min and 300min were carried and the relationship of asphalt performance indexes before and after aging was got as well as four components. The analysis results indicate that: as the aging time increases, change processes of all performance indexes followed curve of index and the correlation coefficient reached significant level. Changing regularity of asphalt four components are also got: the contents of saturate and aromatic both decrease with the aging time increasing, while asphaltene content and resin content increased and the increasing speed of resin is faster. Key words: No.70 road asphalt; four components; performance index; aging.

Abstract: To evaluate the pre and post change of structure strength of old asphalt pavement field hot regeneration, we use the portable falling weight deflectometer method (PFWD) and benkelman beam method (BB) respectively to do the field test research. The field test researches rely on the ANXIN highway old asphalt pavement field hot regeneration project. We got the data about pre and post regenerations asphalt pavement static bending deflection (l0), PFWD dynamic deflection (lp) and PFWD dynamic modulus (EP). The correlation analysis among static bending deflection, PFWD dynamic deflection and PFWD dynamic modulus suggest that PFWD method is a more stable and reliable method than BB method and PFWD method can be a new evaluation technology for the old asphalt pavement field hot regenerations pavement strength.

Abstract: This study is aimed at evaluating the rate of long-term aging of WMA compared to conventional hot-mix-asphalt (HMA). A test section with recorded traffic and weather information was designated in this study. Field cores of two WMAs and one conventional HMA were taken from the field periodically. Both mix and binder properties of retrieved were measured in the laboratory. The resilient modulus and indirect tensile test were performed to characterize mixture properties. The rheological properties of extracted binder were measured by the dynamic shear rheometer (DSR) in order to obtain the complex shear modulus (G*) as well as the phase angle (δ) of binder with and without the WMA additives.