PROJECT DESCRIPTION
BACKGROUND
The development of urban areas, which replaces land and vegetation with buildings, roads and other infrastructure, leads to the formation of urban heat islands (UHI), whereby urban regions experience warmer temperatures than their rural surroundings. The annual mean air temperature of a city with one million people or more can be 1-3°C warmer than its outlying rural areas, but the temperature difference can be as much as 12°C. Even smaller cities and towns produce UHIs, though the effect is less pronounced in smaller urban areas. The impact of climate change could be exacerbated by the UHI effect in urban areas.
This increased attention to heat-related environment and health issues has helped to advance the development of UHI reduction strategies, mainly trees and vegetation, green roofs and cool roofs. Interest in cool pavements has also risen recently: different factors influence UHI development, such as the solar reflectance and thermal emittance of the material used, along with pavement temperatures that is determined by its permeability, convection, thermal conductivity, heat capacity and thickness. Cool pavements have been developed all around the world, though more research and demonstrative projects are needed to help communities to better understand the interactions between pavements and urban climate.
Implementation of the proposed cool pavement technology, however, has not previously been attempted. Much cool pavement development has been carried out on squares or plain areas (e.g. parking lots and sports courts), but not on city roads and not monitored closely.
OBJECTIVES
The LIFE HEATLAND project aimed to demonstrate the mitigation of the UHI effect by using an innovative construction material for road surfaces – cool pavements using a mixture of lime aggregated, transparent synthetic binder and titanium oxide and iron oxides pigments. An innovative pavement would be installed along with four metering towers fitted with diverse sensors (e.g. a pavement surface temperature sensor, three air temperature sensors, an ozone meter and a lux meter) in the city of Murcia. The main objectives of the project were to:
- Demonstrate the effectiveness of the technology to mitigate the UHI effect and to reduce the local temperature;
- Transfer knowledge generated throughout the project to foster replication in other European cities;
- Install innovative pavement in other urban areas, assisted by the project's beneficiaries, or to sign agreements for replication after the end of the project;
- Assess the effect of the new pavement on reducing local energy consumption associated with air conditioning, refrigeration devices and street lighting, along with its contribution to reducing noise and air pollution;
- Validate the socio-economic feasibility of the proposed pavement solution;
- Develop a mathematical model to predict the effectiveness of the technology in different urban areas;
- Apply the mathematical model in several European cities to evaluate the replicability potential of the technology in the EU; and
- Develop dissemination materials and activities, such as reports, guides, a website, seminars and training courses.
The results of the project would help define a new standard for urban pavements that are resilient to the climate change effects. The project is in line with Action VII of the EU strategy on adaptation to climate change by ensuring more resilient infrastructure. The Commission will launch a mandate for European standardisation organisations to start mapping industry-relevant standards in the area of energy, transport and buildings and to identify standards that need to be revised to achieve better inclusion of adaptation considerations.
RESULTS
The LIFE HEATLAND project team proved the effectiveness of an innovative pavement technology to mitigate the Urban Heat Island (UHI) effect. The technology results in cooler pavements, with lighter and more reflective surfaces, having lower solar energy storage compared to traditional pavements.
To develop the demonstrator prototype, 22 000 m2 of reflective pavement and 2 000 m2 of traditional pavement were implemented to compare the performance of both in identical situations. The Barrio del Infante in the city of Murcia (Spain) was selected for the first tests because its characteristics enabled a greater number of streets to be covered.
The new pavement reduced ambient temperature by 1.5ºC and the surface temperature of the pavement by 7-11ºC. The solar reflectance of streets with the more reflective pavement is 23%, 167% higher than that of conventional asphalt. Its lighter colour also greatly improves night visibility, as the luminance of streets with the reflective pavement is 2.0 cd/m2 under streetlights at night, 100% higher than with conventional asphalt, reducing the energy consumption for street lighting. In addition, the new pavement was shown to reduce the noise level by 3 dB(A).
Thanks to the demonstrated benefits of the cool pavement, Barcelona City Council decided to carry out a trial in 2021 on one street of approximately 4 300 m2 (Torrent of l'Olla). The first results showed an increase of 250% in night luminance compared to the previous situation, with solar reflectance rising to 33%, from the 8% of the traditional pavement. Many other public and private entities have since shown an interest in the technology.
The main barrier to further replication is the availability of appropriate manufacturing plants near the implementation areas. To overcome this, project partner CHM has been working on collaboration agreements with other manufacturing companies, which will continue after the project ends. Therefore, the replicability potential for the technology is high.
The LIFE HEATLAND project contributes to the EU Adaptation Strategy, by proving that the innovative cool pavement increases resilience to climate change in urban areas. Social benefits arise from improved citizens' quality of life and well-being.
Further information on the project can be found in the project's layman report (see "Read more" section).
