Physical characteristics of heat-dissipating smart marble at Al Masjid Al-Haram, Makkah City, Saudi Arabia

Abstract

The main objective of this study is to highlight the physical principles responsible for the smart characteristics/nature of the Al Masjid Al-Haram marble (MHM) as compared with the ordinary white marble (OWM). The main issue to address is the lack of experimental data and scientific discussion about the intelligent thermal performance of such a thin stone layer as natural cool material. For this purpose, various physical properties have been studied including the solar reflectivity and thermal conductivity; furthermore, X-ray diffraction (XRD), P-wave velocity Vp, and scanning electron microscopy (SEM) were performed to assess the crystalline quality, internal core structure, and the microstructure characteristics respectively. Results showed that the marble at Masjid Al-Haram is characterized with high thermal conductivity and superior solar reflectivity which help in dissipating the absorbed heat from environmental warm air and the incident solar radiation keeping it always cool. As compared with OWM, the MHM exhibited higher Vp which points to a pore-free characteristic of this marble. SEM micrograph revealed the well-arranged calcite crystals of MHM. XRD patterns indicated that calcite is the major mineral phase present in OWM; however, MHM was dolomite dominant.