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Rutting resistance is an important consideration for paving asphalt mixes. The cause of rutting is a shear strain in the asphalt pavement structure. Here, the rutting behavior of asphalt pavements was evaluated through laboratory simulations using the Hamburg Wheel-Tracking Test (HWTT), UK Wheel-Tracking Test (UKWTT), and Scaled Accelerated Load Simulator (SALS) test. The correlation between the three simulation tests was analyzed to determine the conversion factor (CF). Two parameters of temperature and speed of simulation testing were evaluated in this study. Subsequently, the representative frequency and dynamic modulus were calculated with consideration of viscoelasticity and time-temperature superposition. Using logical analysis, CF between the three simulation tests was validated. The results showed that the full-scale test yielded the highest stiffness modulus of 4,015 MPa, and the UKWTT yielded the lowest stiffness modulus of 1,857 MPa at 60 °C. From the HWTT results, it was found that the impact of moisture damage at 40 °C is not substantial compared to that at 50 °C. The conversion factor of HWTT at 40 °C, HWTT at 50 °C and UKWTT at 60 °C to SALS were 0.92, 0.74, and 0.63, respectively. Furthermore, the similar rutting performance among SALS, HWTT at 40 °C in dry and wet conditions, and HWTT at 50 °C in dry condition can be observed when the CF is applied. Lastly, the effectiveness of the conversion factor is diminished with increasing rutting damage. [ABSTRACT FROM AUTHOR]

In the past decade, numerous studies have shown that incorporating geogrid in the pavement could effectively improve the pavement performance. The major benefit of using geogrid in the flexible pavement is to improve its rutting performance as the result of the reinforcement function of geogrid. Mechanical-empirical pavement design guide (MEPDG) developed to provide the pavement performance prediction throughout its design life. However, MEPDG is not able to consider the effect of incorporating geogrid in the flexible pavement. In this study, a design procedure was proposed to obtain an equivalent geogrid pavement structure, which satisfies MEPDG design input requirements. In this procedure, a 2D finite element method was used to simulate geogrid reinforced and non-reinforced pavement structures. The iteration process based on stress-strain analysis of finite element model (FEM) used to obtain an equivalent structure input for MEPDG. The geogrid reinforced rutting performance can be predicted by analyzing the equivalent geogrid structure using MEPDG. A significant life improvement of pavement with geogrid was observed compared to pavement without geogrid. The results showed that the incorporating of geogrid in asphalt pavement layer significantly reduce the rutting of pavement layer, thus will contribute to extension of pavement service life. [ABSTRACT FROM AUTHOR]

A sustainable roadway rating system (SR2S) consists of a set of indicators to comprehensively measure the sustainability performance of roadway projects. The sustainability level of the systems can be improved by implementing appropriate strategies pertaining to materials and energy. In the peer-reviewed literature, some studies have conducted shallow comparisons of different SR2Ss and no studies have compared the significance of material and energy indicators in existing SR2Ss. To bridge this research gap, five existing SR2Ss were considered. These five SR2Ss described overlapping categories of indicators. Material and energy-related indicators (MEIs) were identified from the representative SR2Ss by conducting content analysis. Similar indicators were regrouped into six different material and energy-related features (MEFs), corresponding to six categories of indicators: local materials; long-life designs; materials obtained using the reduce, reuse, and recycle (3Rs) concept; energy efficiency; earthwork; and hazardous materials. Based on the relative significance index (RSI), the weightings of the selected SR2Ss and the significance of MEIs according to six MEFs were explored. In terms of the aforementioned criteria, the Illinois Livable and Sustainable Transportation gives the greatest weight to material and energy (34.7% of the total points), whereas GreenLITES gives the least weight to material and energy (i.e., 26.8% of total points). Regarding MEFs, SR2Ss focus more on materials obtained by using the 3Rs concept and energy efficiency. This means that indicators pertaining to these two features were considered to contribute significantly to evaluations of roadway sustainability. Aside from 3Rs and energy efficiency, hazardous materials were deemed to be not highly relevant to SR2Ss. Discussion on the indicator requirements related to material and energy are further provided based on different MEFs. [ABSTRACT FROM AUTHOR]