Precast Concrete Pavements of High Albedo to Achieve the Net “Zero-Emissions” Commitments

Miguel Ángel Sanjuán,Ángel Morales,Aniceto Zaragoza

doi:10.3390/app12041955

Abstract

Pavements store heat, which is subsequently released into the atmosphere, heating the surrounding air. Therefore, this process contributes to climate change and global warming. For this reason, the use of high-solar-reflectance (albedo) pavements is seen as one of the potential mitigation methods for climate change. Concrete pavements have a much higher albedo than asphalt due to their light gray color compared with black pavements. Accordingly, the widespread utilization of highly reflective concrete pavements will improve local climate change mitigation. Nevertheless, concrete albedo slightly decreases over time because of weathering. Albedo and solar reflectance index (SRI) measurements were taken on actual precast concrete pavements made with different mixes. The methodology applied for this project is based on the comparison between the asphalt and concrete pavements’ reflectivity. Conventional concrete mix designs can provide cool pavements with SRI higher than 29. Replacement of black pavements by highly reflective concrete pavements appeared to be a cost-effective and easily implemented measure to combat climate change. Finally, multidisciplinary studies considering factors such as building materials’ albedo, among other mitigation measures, should be performed to provide more precise and reliable guidance to policymakers, stakeholders, decision makers and urban planners.

Highlights

According to the law of conservation of energy, radiation of wavelength λ incident upon a material has either been transmitted across the material, has been reflected from its external surface or has been absorbed
The results found in these concrete pavements are compared with the ones reported for the most commonly used materials to construct pavements
There is a linear correlation between the solar reflectance index (SRI) and albedo

Summary

Introduction

According to the law of conservation of energy, radiation of wavelength λ incident upon a material has either been transmitted across the material, has been reflected from its external surface or has been absorbed. Transmissivity (Ψλ), reflectivity (αλ) and absorptivity (ζλ) are defined as dimensionless numbers between zero and the unity, according to Equation (1). They are radiative properties of the material. Equation (1) is valid exclusively for the case of a single wavelength. It is acceptable for fairly wide range of wave bands. The value of the reflectivity, α, directly determines the absorptivity of an opaque surface

Methods

Results

Conclusion