energia: Environmental impact of concrete

Evidence: 100 • authority: 72

The environmental impact of concrete, its manufacture, and its applications, are complex, driven in part by direct impacts of construction and infrastructure, as well as by CO2 emissions; between 4-8% of total global CO2 emissions come from concrete. Many depend on circumstances. A major component is cement, which has its own environmental and social impacts and contributes largely to those of concrete. In comparison with other construction materials (aluminium, steel, even brick), concrete is one of the least energy-intensive building materials. The cement industry is one of the main producers of carbon dioxide, a greenhouse gas. Concrete is used to create hard surfaces which contribute to…

Evidence: 77 • authority: 88

Albedo of Pervious Concrete and Its Implications for Mitigating Urban Heat Island. Urban heat islands have become a growing concern in many cities around the world. Pervious pavements have been proposed as a potential solution to mitigate this effect, but their effectiveness in reducing surface temperatures is still uncertain. This experimental study aims to investigate the reflectivity of pervious concrete to determine whether pervious pavements are cooler than conventional pavements. To achieve this, five different Portland cement concrete mixes are used to create pervious concrete samples with varying porosity levels. The samples are sliced, and their spectral reflectance and albedo are…

Evidence: 69 • authority: 88

Urban Heat Island High Local Water-Vapor Feedback Estimates Requiring Albedo Management. Abstract In this paper, we analyze warming data on Urban Heat Islands (UHI) in dry versus humid environments to estimate local water-vapor feedback from city growth. We find looking at such data and comparing rural to urban areas, UHI local water-vapor feedback is about 3 W/m 2 / o K to a maximum of 4 W/m 2 / o K. Relative to global climate feedback estimates of about 2 W/m 2 / o K, this is a factor of 1.5 to 2 times higher. This UHI effect is observed during daytime hours. Water-vapor feedback is known to be one of the most important in our climate system and thought that it can double the direct known…

Evidence: 60 • authority: 72

Cool pavement is defined by the United States Environmental Protection Agency as pavement that implements technologies contributing to heat island effect reduction efforts. Most cool pavements either increase pavement albedo to reflect shortwave radiation out of the atmosphere and reduce heat transfer to the Earth's surface, or use evaporative water cooling through the pavement to lower ambient temperatures. Newer technologies involve energy harvesting, heat storage methods, and phase change materials. Cool pavements are commonly made with reflective coatings or aggregates applied to conventional pavements or incorporation of porous or permeable materials. While pavement load capability may…

Evidence: 60 • authority: 72

The urban heat island (UHI) effect is a meteorological and climatological phenomenon in which urban areas experience significantly warmer temperatures than surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak, under block conditions, noticeably during the summer and winter. The main cause of the UHI effect is from the modification of land surfaces, while waste heat generated by energy usage is a secondary contributor. Urban areas occupy about 0.5% of the Earth's land surface but host more than half of the world's population. As a population center grows, it tends to expand its area and increase its avera…

Evidence: 60 • authority: 88

High Albedo Interlocking Concrete Block Pavement for Urban Heat Island Mitigation. The combined effects of global warming and urbanisation have intensified the urban heat island (UHI) phenomenon and thermal stress, especially in the summer season. This study develops an integrated multi-scale framework to quantify the sustainability in terms of the thermal performance of high albedo interlocking concrete block pavement (ICBP) in the city of Turin, Italy. The framework combines: (1) experimental campaigns to establish baseline albedo values, using an albedometer (in accordance with the standard ASTM E1918-21 and E1980-24); (2) in situ measurements to assess the performance of ICBP in three p…

Evidence: 58 • authority: 80

Investigation into the effect of pavement albedo and environmental factors on urban heat island effect using CFD simulation

Evidence: — • authority: 92

Spectrally Selective Daytime Radiative Cooling Coating.. Passive daytime radiative cooling offers a carbon‑free route to mitigate urban heat islands and reduce building energy use. Conventional broadband emitters, however, suffer from parasitic absorption of ambient thermal radiation from hot ground and adjacent buildings, severely compromising net cooling in dense urban settings. We present a scalable, spectrally selective radiative cooling coating that overcomes this urban penalty. By combining a phase‑inversion‑derived micro‑nano porous poly (vinyl fluoride) (PVF) layer with a reflective silver substrate, our emitter achieves a record spectral selectivity of 1.37, with 97.5% solar reflec…

Evidence: — • authority: 92

Asymmetric global urban cooling potential demands accelerated and context-specific actions.. Rising urban temperatures and heat extremes pose an urgent global challenge, yet the potential for mitigating excessive urban heat-particularly at the global scale-remains unclear. Here, we quantify the cooling potential across 2,265 cities worldwide by the 2050s using validated urban climate simulations. Cooling effects are quantified as the reduction in the summer average wet-bulb globe temperature (WBGT) and heat danger hours (HDH; WBGT > 31.4 °C) under the combined implementation of reflective surfaces, green transformation, and anthropogenic heat reduction. We show a distinct spatial asymmetry:…

Evidence: — • authority: 92

Influence of Ground Granulated Blast-Furnace Slag on Solar Reflectance, Lightness, and Temperature of Hardened Cement Paste Surface.. The solar reflectance (SR) of surfaces in the built environment influences the urban heat island phenomenon, while surface lightness ( L * in color measurement) serves as an indicator of surface appearance. Both parameters are closely related to the surface temperature ( T s ), which affects thermal comfort and building energy performance. Ground granulated blast-furnace slag (GGBS) is a whitish supplementary cementitious material. High-volume replacement of cement with GGBS can significantly lower the carbon footprint of cement-based materials. This study sy…

Evidence: — • authority: 92

Preliminary Field Performance of a Low-Tortuosity Permeable Pavement System Incorporating Bottom Ash Fine Aggregate for Surface-Temperature Regulation and Stormwater Storage.. Rapid urbanization has intensified two critical urban challenges: the urban heat island effect and stormwater runoff. This study evaluates the pilot-level field performance of a low-tortuosity permeable pavement (LTPP) system in potentially contributing to improved thermal regulation and hydraulic functionality. The system comprises a reduced-tortuosity upper block incorporated with bottom ash (BA) as a recycled fine aggregate and an underlying storage unit connected through an interlocking configuration, enabling dir…

Evidence: — • authority: 92

Identifying the best combination of vegetation and paving materials to improve the outdoor thermal comfort in a campus courtyard.. The urban heat island effect poses significant challenges to urban residents by diminishing thermal comfort and altering outdoor behaviors in hot environments. Although improvements in green space and adjustments to paving materials can alleviate these impacts, their combined effects remain insufficiently studied. This study employed ENVI-met software to simulate nine vegetation-paving material combinations and assess their influence on the thermal environment and thermal comfort of a campus courtyard during summer. Regression analyses were conducted to explore…