Development of Super Road Heat-Reflective Coating and Its Field Application

Heat-reflective coatings, used to reduce the asphalt pavement temperature and urban heat island effect, have a good cooling effect; coating development, however, generally focuses on cooling. This study aims to design a heat-reflective coating with both durability and cooling effect by considering the functions of each component, improving the coating bond strength and abrasion resistance, and conducting laboratory tests and test section verification. The coating developed exhibits bond strength and abrasion resistance 20% and 49%, respectively, higher than those of ordinary coatings. The experiments reveal a cooling effect of red coating up to 10.2 °C, a bond strength of up to 1.20 MPa at 25 °C, and an abrasion rate of up to 25% after 60 min; the cooling effect is basically the same as that for traditional heat-reflective coatings, but the bond strength and abrasion resistance significantly improved. In the analysis of the test section, the cooling effect reaches 7.0 °C, the performance of anti-skid decreases little, and the coating is still usable normally after 4 months.

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Cooling Effect of Different Land Cover Types: A Case Study in Xi’an and Xianyang, China

Sustainability ◽

10.3390/su13031099 ◽

2021 ◽

Vol 13 (3) ◽

pp. 1099

Author(s):

Yuhe Ma ◽

Mudan Zhao ◽

Jianbo Li ◽

Jian Wang ◽

Lifa Hu

Keyword(s):

Land Cover ◽

Surface Temperature ◽

Urban Heat Island ◽

Land Surface Temperature ◽

Land Surface ◽

Cooling Effect ◽

Heat Island ◽

Land Cover Types ◽

Island Effect ◽

Urban Heat

One of the climate problems caused by rapid urbanization is the urban heat island effect, which directly threatens the human survival environment. In general, some land cover types, such as vegetation and water, are generally considered to alleviate the urban heat island effect, because these landscapes can significantly reduce the temperature of the surrounding environment, known as the cold island effect. However, this phenomenon varies over different geographical locations, climates, and other environmental factors. Therefore, how to reasonably configure these land cover types with the cooling effect from the perspective of urban planning is a great challenge, and it is necessary to find the regularity of this effect by designing experiments in more cities. In this study, land cover (LC) classification and land surface temperature (LST) of Xi’an, Xianyang and its surrounding areas were obtained by Landsat-8 images. The land types with cooling effect were identified and their ideal configuration was discussed through grid analysis, distance analysis, landscape index analysis and correlation analysis. The results showed that an obvious cooling effect occurred in both woodland and water at different spatial scales. The cooling distance of woodland is 330 m, much more than that of water (180 m), but the land surface temperature around water decreased more than that around the woodland within the cooling distance. In the specific urban planning cases, woodland can be designed with a complex shape, high tree planting density and large planting areas while water bodies with large patch areas to cool the densely built-up areas. The results of this study have utility for researchers, urban planners and urban designers seeking how to efficiently and reasonably rearrange landscapes with cooling effect and in urban land design, which is of great significance to improve urban heat island problem.

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Combating Urban Heat Island Effect—A Review of Reflective Pavements and Tree Shading Strategies

Buildings ◽

10.3390/buildings11030093 ◽

2021 ◽

Vol 11 (3) ◽

pp. 93

Author(s):

V. R. Sankar Cheela ◽

Michele John ◽

Wahidul Biswas ◽

Prabir Sarker

Keyword(s):

Urban Heat Island ◽

Urban Forest ◽

Critical Role ◽

Tree Canopy ◽

Mitigation Measures ◽

Heat Island ◽

Human Thermal Comfort ◽

Urban Heat ◽

Pavement Temperature ◽

Reflective Coatings

Pavements occupy about 40% of urban land cover, with 75–80% black top roads, playing a critical role in urban connectivity and mobility. Solar energy is absorbed and stored in pavements leading to an increase in surface temperatures. Decreasing green cover is further contributing to rise in regional temperatures. Due to this activity, the city experiences urban heat island (UHI). This study presents a critical review of the literature on mitigation measures to combat UHI using reflective pavements with an emphasis on durability properties and impacts of tree canopy. The strategies with a focus on application of chip seals, white toppings, and coatings were discussed. Role of surface reflectance, including those from asphalt and concrete pavements, albedo improvements, and technological trends, application of waste materials, and industrial by‐products are presented. Also, urban tree shading systems’ contribution to pavement temperature and microclimate systems is presented. The review shows that the development of mitigation measures using tree shading systems can reduce the pavement temperature during daytime and increase human thermal comfort. The outcomes of this review provide a scope for future studies to develop sustainable and state‐of‐the-art engineering solutions in the field of reflective coatings and urban forest systems.

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Cooling Effect of Waste Fiber Culture Medium Used as Extensive Green Roof

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.860-863.1219 ◽

2013 ◽

Vol 860-863 ◽

pp. 1219-1222

Author(s):

Jing Chzi Hsieh ◽

Jia Hsun Li ◽

Jia Horng Lin

Keyword(s):

Culture Medium ◽

Load Capacity ◽

Green Roof ◽

Cooling Effect ◽

Control Group ◽

Extensive Green Roof ◽

Island Effect ◽

Ecological Protection ◽

Urban Heat ◽

And Control

Greening on roofs that are not totally used can create a good cooling effect and mitigate the urban heat island effect. Considering the load capacity of roofs and ecological protection, this study thus uses fiber waste to make culture mediums as an extensive green roof, after which sedum makinoi is then planted to evaluate the cooling effect of the waste fiber culture medium. The experimental results show that sedum makinoi planted with waste fiber culture medium can averagely reduce the temperature of the roof surface by 5 °C and to a maximum of 11.8 °C. Although experimental group and control group both have the same cooling effect, waste fiber culture medium which is much lighter than that of the control group, and it also has a life-cycle, an energy-saving, ecological friendly merit, both of which qualify it for use of the culture medium as extensive green roof.

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Lab-Controlled Experimental Evaluation of Heat-Reflective Coatings by Increasing Surface Albedo for Cool Pavements in Urban Areas

Coatings ◽

10.3390/coatings12010007 ◽

2021 ◽

Vol 12 (1) ◽

pp. 7

Author(s):

Yang Lu ◽

Md Asif Rahman ◽

Nicholas W. Moore ◽

Aidin J. Golrokh

Keyword(s):

Urban Areas ◽

Surface Albedo ◽

Weather Conditions ◽

The Body ◽

Halogen Lamp ◽

Reflective Coating ◽

Viable Solution ◽

Urban Heat ◽

Reflective Coatings ◽

The City

Many studies were conducted to find possible strategies for reducing the urban heat island (UHI) effect during the hot summer months. One of the largest contributors to UHI is the role that paved surfaces play in the warming of urban areas. Solar-reflective cool pavements stay cooler in the sun than traditional pavements. Pavement reflectance can be enhanced by using a reflective surface coating. The use of heat-reflective coatings to combat the effects of pavements on UHI was previously studied but no consistent conclusions were drawn. To find a conclusive solution, this work focuses on the abilities of heat-reflective pavement coatings to reduce UHI in varying weather conditions. Within this context, both concrete and asphalt samples were subject to a series of performance tests when applied to a heat-reflective coating, under the influence of normal, windy, and humid conditions. During these tests, the samples were heated with a halogen lamp and the surface temperature profile was measured using an infrared thermal camera. The air temperature was recorded with a thermometer, and the body temperature at multiple depths of the samples was measured using thermocouples. The results from these tests show that the effectiveness of the heat-reflective coating varies under different weather conditions. For instance, the coated samples were about 1 °C cooler for concrete and nearly 5 °C cooler for asphalt, on average. However, this temperature difference was reduced significantly under windy conditions. As such, the findings from this work conclude that the heat-reflective coatings can effectively cool down the pavement by increasing the surface albedo, and thus might be a viable solution to mitigate UHI impacts in the city/urban areas.

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Detecting the Cool Island Effect of Urban Parks in Wuhan: A City on Rivers

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18010132 ◽

2020 ◽

Vol 18 (1) ◽

pp. 132

Author(s):

Qijiao Xie ◽

Jing Li

Keyword(s):

Remote Sensing ◽

Negative Impact ◽

Remote Sensing Data ◽

Urban Parks ◽

High Water ◽

Water Bodies ◽

Green Spaces ◽

Heat Island ◽

Island Effect ◽

Urban Heat

As a nature-based solution, development of urban blue-green spaces is widely accepted for mitigating the urban heat island (UHI) effect. It is of great significance to determine the main driving factors of the park cool island (PCI) effect for optimizing park layout and achieving a maximum cooling benefit of urban parks. However, there have been obviously controversial conclusions in previous studies due to varied case contexts. This study was conducted in Wuhan, a city with high water coverage, which has significant differences in context with the previous case cities. The PCI intensity and its correlation with park characteristics were investigated based on remote sensing data. The results indicated that 36 out of 40 urban parks expressed a PCI effect, with a PCI intensity of 0.08~7.29 °C. As expected, larger parks with enough width had stronger PCI intensity. An increased density of hardened elements in a park could significantly weaken PCI effect. Noticeably, in this study, water bodies in a park contributed the most to the PCI effect of urban parks, while the vegetated areas showed a negative impact on the PCI intensity. It implied that in a context with higher water coverage, the cooling effect of vegetation was weakened or even masked by water bodies, due to the interaction effect of different variables on PCI intensity.

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