Abstract:
The urban heat island (UHI) effect is an
important environmental challenge in rapidly developing
urban areas, where built surfaces can reach substantially
higher temperatures than surrounding areas. Pavement
materials contribute to this phenomenon by absorbing
and storing solar energy during daytime exposure. This
study investigates the thermal and mechanical
performance of a phase change material (PCM)-
enhanced concrete pavement developed to reduce
pavement surface temperatures under tropical outdoor
conditions. Paraffin wax was selected as the PCM because
of its phase-change temperature range suitable for the
experimental conditions, while expanded clay aggregate
(ECA) was used as a porous carrier for PCM
incorporation. Four pavement mixtures containing 0%,
3%, 6%, and 9% PCM-integrated ECA were prepared,
with the PCM-containing material incorporated within
the upper surface layer of the pavement specimens. The
thermal performance was evaluated through outdoor
monitoring over a 15-day period at one-hour intervals.
Compressive strength was evaluated at 7, 14, and 28 days,
while flexural strength was evaluated at 28 days. The
results showed that PCM incorporation reduced the peak
pavement surface temperature compared with the control
specimen. The 3%, 6%, and 9% PCM mixtures reduced
the peak surface temperature by approximately 3.5 °C,
6.0 °C, and 6.5 °C, respectively. Although increasing
PCM content improved thermal performance, the
additional reduction between 6% and 9% was relatively
small. The 6% PCM mixture provided a balance between
thermal performance and mechanical strength, with a
reported 28-day compressive strength of 27 MPa and
flexural strength of 3.12 MPa. The findings indicate that
PCM-integrated concrete pavement has potential for
reducing pavement surface temperatures under tropical
outdoor conditions. However, further investigation is
required to evaluate long-term durability, environmental
implications, thermal cycling behaviour, and the
potential contribution of the technology to urban-scale
UHI mitigation.
