Light-coloured concrete surfacing for urban heat-island mitigation in Southern Africa

Global population growth and rapid urbanisation have resulted in the rapid transformation of natural topographies that are now dominated by engineering materials and structures. It is widely recognised that economic development is largely attributable to infrastructure development. However, this dev...

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Bibliographic Details
Published in:	Journal of the South African Institution of Civil Engineers Vol. 64; no. 2; pp. 2 - 12
Main Authors:	Mlilwana, T P, Kearsley, E P
Format:	Journal Article
Language:	English
Published:	Johannesburg South African Institution Of Civil Engineering (SAICE) 01-06-2022 Sabinet Online The South African Institution of Civil Engineers
Subjects:	Absorptivity Analysis Civil engineering Climate change Concrete Concrete construction Concrete structures Economic development Finite element method Global temperature changes Heat island Infrastructure Material properties Mathematical models Parameter sensitivity Population growth Portland cement concrete South Africa Surface chemistry Surface properties Surfacing Thermal environments Thermal mass Thermal performance Urban heat islands Urbanization South Africa Southern Africa
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Summary:	Global population growth and rapid urbanisation have resulted in the rapid transformation of natural topographies that are now dominated by engineering materials and structures. It is widely recognised that economic development is largely attributable to infrastructure development. However, this development has come about with adverse consequences. In this paper, the effects of surface characteristics, climatic parameters and material properties on the thermal environment and near-surface heat islands in urban areas were investigated. An experiment was conducted in which simple concrete structures with varying surface characteristics were constructed and instrumented. The effect of solar absorptivity was clearly visible, with structures surfaced with low absorptivity materials exhibiting lower surface and effective temperatures. Following the experimental programme, numerical simulations of the simple concrete structures were performed using finite element modelling. The analyses showed that the thermal environment of concrete structures is sensitive to changes in solar absorptivity, climatic parameters, cross-sectional dimensions, and material properties. It was found that the use of low absorptivity or highly reflective surfacing and the selection of appropriate dimensions can be used to significantly reduce the temperatures of concrete infrastructure, including buildings and pavements, thereby providing an evidential basis for the use of low absorptivity surfacing materials to mitigate climate change in Southern Africa.
ISSN:	1021-2019 2309-8775
DOI:	10.17159/2309-8775/2022/v64no2a1