| Abstrakt: |
The temperature increase in cities called the "urban heat island" (UHI) depends on the local microclimate (e.g., solar irradiation, population, buildings density, industrial activities, traffic, emissions, heat sources) and results not only in increased electricity consumption for indoor cooling but also in decreased outdoor comfort, especially in summer periods or in warm climate zones. As the world's urban population continues to grow, there is an urgency to make buildings more ecoefficient and reduce the impact of cities on climate change and global warming. In this framework, the use of cool concretes can mitigate the UHI and improve energy saving and outdoor comfort: cool concrete roofs and facade cement-based tiles can provide valid solutions to decrease the energy demand for air conditioning in building envelops; moreover, cool concrete paving blocks and pervious pavements can improve urban comfort for outdoor wellbeing. The present work shows the improved solar reflective performance of three cool cementitious solutions compared with traditional ones, with both white and colored surfaces, to fulfill both architectural demand and sustainability issues without any additional post-treatments or after placing steps, such as surface coating. Finally, the study is completed with the durability evaluation of the products' solar reflective performance. Tackling urban and global warming is one of the most urgent actions to make cities safer and more sustainable as well as to improve citizens wellbeing. From an optical performance perspective, it has been proved that traditional concrete-based materials do play a significant role in contributing to the fight against urban heat island phenomena when functionalized with high-reflective cool materials. Indeed, the near-infrared (NIR)-reflective concrete-based materials, which are the subject of this paper, can participate in mitigating both outdoor pavements and building surfaces temperature, regardless of their color. Lighter or darker concrete surfaces can reflect the sunlight not only in the visible range of the solar spectrum, thanks to lighter nuances, but also in the NIR region, that is, the main area responsible for the surface heating. In addition, we have successfully tested this ability in severe accelerated ageing conditions. The durable—white and colored—concrete tiles here described for building envelopes as well as urban draining or self-locking concrete pavements widen the horizon for more and more sustainable opportunities as well as flexible solutions, matching both modern architecture's technical and social requirements. [ABSTRACT FROM AUTHOR] |
