Economic and social development of urban and rural areas continues in parallel with the increase of the human population, especially in developing countries, which leads to sustained expansion of impervious surface areas, particularly paved surfaces. The conversion of pervious surfaces to impervious surfaces significantly modifies local energy balance in urban areas and contributes to urban heat island (UHI) formation, mainly in densely developed cities. This paper represents a literature review on the causes and consequences of the UHI and potential measures that could be adopted to improve the urban microclimate. The primary focus is to discuss and summarise significant findings on the UHI phenomenon and its consequences, such as the impact on human thermal comfort and health, energy consumption, air pollution, and surface water quality deterioration. Regarding the measures to mitigate UHI, particular emphasis is given to the reflective and permeable pavements.

The urban heat island (UHI) effect poses significant challenges to urban environmental quality and public health. Over the decades, research efforts have been made to develop various UHI mitigation strategies, including pavement materials, such as, water-retentive pavement, reflective pavement, and pervious concrete. This paper focuses on the improvement of the hygric and water retention properties of pervious concrete to mitigate UHI phenomena. The hydric and hygroscopic tests were carried out under dry and wet conditions on four different pervious concretes, where natural aggregates were replaced with recycled aggregates at different mass percentages. The results show a significant improvement in these properties by increasing the amount of recycled aggregates incorporated in the mixtures. The mixes made from recycled aggregates alone showed an absorption that reached 75 L more than the control in one cubic meter under wet condition. With an upwelling capacity of up to 30 kg of retained water in a square meter under dry condition, these improvements in water performance represent this permeable concrete as a water retention pavement solution for UHI mitigation. Regarding the mechanical properties, a decrease of 50% in compressive strength was noted only when 100% of the recycled aggregate was incorporated, remaining at 20 MPa for other mixtures.