The document discusses cool pavements, which are pavement surfaces designed to reduce the urban heat island effect. It first introduces the topic and defines urban heat islands as metropolitan areas that are often warmer than surrounding rural areas due to human activity and dark pavements. It then describes different types of cool pavements, including reflective and permeable pavements, and provides examples like Portland cement concrete, white-topping, asphalt sealcoats and coatings. Benefits of cool pavements are also listed, such as improved water quality, safety and reduced nighttime temperatures. The document concludes by noting that cool pavements provide a cost-effective way to lower urban temperatures compared to conventional dark surfaces.

1. COOL PAVEMENTS

2.  INTRODUCTION
 HEAT- ISLANDS
 COOL PAVEMENT
 TYPES OF COOL PAVEMENTS
 BENEFITS OF COOL PAVEMENTS
 CONCLUSION
 REFERENCES
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3.  A means of reducing UHI effect
 Materials chosen to reduce pavement temperature
 Either reflect solar energy or are porous
 Store less heat
 Economical – do not require new materials
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4.  Cities are often warmer than rural areas
 UHI is a microclimatic phenomenon which occurs in the
metropolitan areas.
 Results in temperature differences up to 10°C
 Human activity, combined with dark pavements make cities
hotter than surrounding rural areas.
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5. Albedo
 Fraction of solar energy reflected from the earth back into
space
 Varies between 0 and 1
 0 meaning black
 1 meaning white
 White surface is a “perfect reflector”
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7.  Increase Pavement Surface Reflectance
 Increase Pavement Thermal Emission
 Increase Pavement Surface Convection
 Reduce Pavement Thermal Conductivity
 Reduce Pavement Heat Capacity
 Evaporation Cooling
 Shading Pavements
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8.  REFLECTIVE PAVEMENTS
 Increasing the solar reflectivity of a pavement surface
 Using surfacing materials of light colour or applying light
colour coating on dark surfacing materials
 PERMEABLE PAVEMENT
 Contains more air voids than conventional pavements
 Designed to allow water to drain through the surface into
the sub layers and down into the groundwater
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9.  Portland Cement Concrete Paving
 White-topping
 Asphalt Emulsion Sealcoats
 Asphalt Slurry Seals
 Asphalt Surface Coatings
 Resin Modified Emulsion Pavement
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10.  It is proposed as cool pavement because of its light colour and
reflectivity
 Used in new construction and reconstruction
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11.  A concrete pavement is applied over an existing asphalt
pavement
 Addition of fiber reinforcement leads to new concrete
mixture, called ultra-thin white-topping
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12.  Fine aggregates in emulsion with an asphalt binder
 Brushed on over existing pavements
 Seal small cracks and protect the surfaces
Asphalt slurry seals
 Asphalt emulsion with graded aggregates
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 binder made primarily from tree resins
 High strength and resistance to fuel spills

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 Pervious concrete pavement
 Porous asphalt
 Permeable interlocking concrete pavement

16.  Porous, gap-graded or enhanced porosity concrete
 Concrete with reduced sand or fines
 Reduced fines leave stable air pockets in the concrete
 Allows storm water to flow through the concrete
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17.  Pervious, popcorn or open-graded asphalt
 Standard hot-mix asphalt with reduced sand or fines
 Reduced fines leave stable air pockets in the concrete
 Allows storm water to flow through the asphalt
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18.  Designed with small openings between permeable joints
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19.  Water quality
 Noise
 Safety
 Nighttime illumination
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 Reflected illumination is proportional to solar reflection

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 About 40% of urban surfaces are paved
 One reason for cities being hot is that have many dark
surfaces
 Cool surfaces are a cost-effective and simple way to achieve
reduced urban temperatures in pavements.

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 Doulos, L., Santamouris, M., and Livada, I. (2004), “Passive cooling of outdoor
urban spaces. The role of materials.” Solar Energy, 77(2), 231–249.
 Santamouris M: Using cool pavements as a mitigation strategy to fight urban heat
island—A review of the actual developments. Renewable and Sustainable Energy
Reviews. In Press, 2013
 Jim Grove, Suneel vanikar and leif wathne, (2011).”Sustainability opportunities for
concrete pavements” Indian concrete journal, march 2011, volume 85, november3,
7-15
 Cambridge systematic.2005.cool pavement draft report prepared for Heat island
reduction initiative, U.S. Environmental Protection Agency.
 Patrica Romero Lankao (2008)”urban areas and climate change: Review of
Current issues and Trends”-issued paper for the 2011 Global report on Human
settlement –Ph D, Institute for the study of society and environment.
 case study_ Natural Stone Solar Reflectance Index and the Urban Heat Island
Effect prepared by the university of Tennessee centre for clean products –July 17
2009M

23. THANK YOU