The global phenomenon of rapid urbanization is forcing the transition of native vegetation to man-made engineered surfaces resulting in the urban heat island (UHI) effect. The UHI can adversely impact the sustainability of regions by increasing the dependence of mechanical cooling which results in increased greenhouse gas emissions, consumption of water in the thermoelectric process and increased costs of living for regional residents. The UHI can also increase the incidence and severity of heat related illnesses as well as alter sensitive ecological systems. Mesoscale remote sensing was acquired and reviewed to identify the role of surface pavements on the UHI in the Phoenix region. The imagery provided coarse visual representation of the paved surfaces, including local roads, highways and parking lots pavements; they showed a noteworthy role in regards to the UHI as well as distinguishing variability of surface temperatures related to spatial patterns, pavement material type, location and surrounding landscape. Remote sensing was also used to demonstrate the usefulness of capturing and analyzing surface materials, comparing soil and vegetation indices, albedo and surface temperatures. Handheld IR thermography was also utilized in examining contributing factors and mitigation techniques to the UHI. The findings of this study indicated that both mesoscale satellite remote sensing imagery and microscale handheld IR thermography are useful tools for defining and evaluating pavement surfaces temperatures and their contribution to the UHI. However, both have limitations in their use based on the study of interest.

This research presents a laboratory investigation into the effects of polyolefin and aramid fibers as a reinforcement material in hot-mix asphalt (HMA) mixtures, with different asphalt binders. Three commercially available asphalt binders were used: asphalt cement penetration grade AC60/70, natural rubber–modified asphalt (NRMA), and polymer-modified asphalt (PMA). The effect of fiber reinforcement in those asphalt mixtures was evaluated by a detailed laboratory experimental program, which included Marshall stability, indirect tensile strength (ITS), resilient modulus ($M_R$ ), indirect tensile stiffness modulus (ITSM), dynamic creep, diametrical indirect tensile fatigue, and rutting resistance tests. The performance evaluation was performed by comparing the results between asphalt mixtures with and without fiber reinforcement for the AC60/70, NRMA, and PMA. The laboratory results indicate that without fiber reinforcement, the PMA exhibited better performance than NRMA and AC60/70, respectively. The addition of fibers 0.05% by mass of the total mixture to asphalt concrete mixtures notably improved the rutting resistance, fatigue life, and resilient modulus, regardless of asphalt binder type. The average values of Marshall stability, $M_R$ , ITS, and ITSM of all the fiber-reinforced mixtures was increased by approximately 17, 31, 11, and 33%, respectively, compared with the mixtures without fiber reinforcement. This research confirms that fiber-reinforced asphalt pavements exhibit superior performance to traditional asphalt concrete pavement, hence resulting in longer service life.

A recent study at Arizona State University has shown that the phase angle, φ, was a good laboratory parameter to distinguish the asphalt mixture's tyre/pavement noise characteristics in the field. The phase angle is obtained simultaneously from the E* dynamic complex modulus test (AASHTO TP 62-03). In particular, the peak or maximum phase angle obtained from the range of the E* test frequencies provided the best indication of the mixture's noise-dampening response. The objective of this study was to utilise the φ–E* relationships to develop appropriate master curves for the phase angle parameter. In addition, the objective was to develop predictive phase angle models so that they can be used to assess the dampening response, and therefore the tyre/pavement noise characteristics of the different asphalt mixtures. E*–φ results from 217 conventional and crumb rubber-modified asphalt mixtures were used in the analysis. The beta distribution was found to best fit the phase angle master curve relationship and the statistical goodness-of-fit parameters were found to be excellent. Phase angle predictive equations were modelled with combinations of mixture properties such as aggregate gradations, binder viscosity–temperature susceptibility parameters, asphalt content, mixture air voids, temperature and loading frequency. Over 6510 data points were included in the development of the phase angle predictive equations. They included equations for both conventional and crumb rubber-modified mixtures. The predictive equations had very good to excellent goodness-of-fit statistics.

Climate change is undoubtedly affecting the global weather of the Earth. Rapid human civilization has mainly caused this in the last few decades. This research examined the spatial and temporal land surface temperature (LST) in the United Arab Emirates (UAE) coastal cities located in an arid region that faced massive urbanization over the last 50 years. We estimated the LST using by-products of Landsat and MODIS images covering 2000 until 2020. The assessment of LST was performed in two contexts, i.e., spatially and temporally, covering daytime vs. nighttime during the summer and winter seasons. Additionally, a supervised classification technique was adopted to extract the land use and land cover in the study area from the late 1970s until 2018. Unexpectedly, the results indicated that daytime LST in districts near the coastlines (heavily urbanized areas) are lower than the ones far away from the coast (about 9 °C). This observation represents the spatial LST inversion in the study area. Nevertheless, this difference was not observed during nighttime LST temporally, the daytime LST did not increase significantly during either summer or winter seasons. However, the nighttime LST has increased temporally by about 17% since 2000 (the temporal LST inversion). Both LST inversions could be attributed to the uniqueness of the study area, given that bare land desert was replaced by vegetation, high-rise buildings, and industrial activities. Additionally, the wind breeze blowing from the gulf might potentially contribute to cooling the coastal urban area during the daytime. Furthermore, in-depth zonal statistics were conducted to visualize the effect of land use on LST. The study observed that fully built-up areas with vegetation have lower LST than built-up areas without vegetation or a combination of sand and vegetation. The research outcomes are invaluable for decision-makers and researchers in achieving sustainable urban development.

Cracking is one of the most common distresses in asphalt pavement. Because asphalt concrete is relatively weak in tension, synthetic fibers have shown to increase its tensile strength and, therefore, reduce the chance of cracking. An approach was used in this study with the aim of evaluating the interaction between fibers and asphalt mastic and the fiber distribution in asphalt concrete. Three types of aramid fibers and two types of nylon fibers were used. A pullout test was used to determine the typical shear bond strength between fibers and the asphalt mastic. The bond strength obtained from the pullout test was then used to calculate the minimum fiber embedded length on each side of the crack in order for the fiber to reach its full capacity before being pulled out. Of course, increasing fiber length increases the chance of bridging cracks considering the random distribution of fibers in fiber-reinforced asphalt concrete (FRAC) and the random orientation of fibers relative to cracks. On the other hand, increasing fiber length may result in uneven distribution of fibers in the FRAC. Fiber extraction and recovery tests were then used to determine the dispersion of aramid fibers in the FRAC with different fiber lengths. The study showed that aramid fibers in the order of 20 mm would provide a good bond with the asphalt mastic and result in reasonable dispersion in the FRAC. The uniaxial fatigue test and flow number test were also performed on FRAC with different aramid fiber lengths. The 19-mm fibers also showed better performance test results than the 10- and 38-mm fibers. A similar length is recommended for the Nylon 1 fibers based on the bond properties only. Longer Nylon 2 fibers are recommended, but caution needs to be taken to avoid uneven fiber dispersion in the FRAC.