Traffic noise is the perpetual form of environmental pollution adversely affecting human health in urban environments. This literature review, intended for pavement researchers and professionals, looks at the continuously evolving low-noise asphalt pavement technologies and the techniques which can be used to evaluate them. Test methods for determining the acoustical properties of asphalt pavements are reviewed, in both the laboratory and field environments. The Close-Proximity (CPX) method is the most commonly used field test for pavement acoustics, followed by the Statistical Pass-By (SPB) and On-Board Sound Intensity (OBSI) methods. SPB seems is the most comprehensive methods, while the CPX is more practical. Methods for measuring the acoustical properties in the laboratory include the impedance tube for sound absorption and laboratory pavement noise simulators; with only the larger drum methods being able to produce conditions similar to in-situ. Methods for noise-relevant non-acoustical characteristics like surface texture, porosity and airflow resistivity were also reviewed. Optimizing surface texture at the macro-scale was found to be important in reducing tire/road noise. For pavement types, porous asphalt concrete (PAC) and its variants result in low-noise properties the most reliably, while having some drawbacks in durability and maintenance. Finally, various acoustical performance prediction models were discussed.

Temperature is significantly influencing the behaviour of asphalt road surfaces. In case of cooling, asphalt pavements become stiffer eventually reaching a brittle state at which thermal cracking may occur. Phase change materials (PCM) respond to the environmental changes by actively altering their own properties by absorbing, storing, or releasing heat without changing their own temperature. Nevertheless, the application of phase change materials in thermoplastic materials, such as asphalt, has drawn attention only recently. The current study aims with an innovative approach for buffering and controlling extreme low temperatures in asphalt road surfaces by incorporating PCM as an additive for storing heat energy in a latent form. However, the results showed that the addition of Tetradecane as raw PCM material into the bitumen 10/20, 70/100 and 160/220 drastically increased penetration and decreased the conventional characteristics such as softening temperature as well as the complex modulus. The results of this study reveal that the direct interaction of Tetradecane with bitumen significantly affects the rheological properties of bitumen without storing heat energy in a latent form. Therefore, the choice of a suitable PCM and its incorporation in bitumen (e.g. microencapsulation, shape stabilisation) and possible leakage of protected PCM due to breakage of shell is very important in the context of bitumen modification.