**2.3.7 Vegetal surfaces**

428 Solar Radiation

light grain and 39 oC (Tair+4.5 oC) for the heavy grain sample, While the grey samples had high surface temperatures, reaching 55.6 oC (Tair+21.1 oC) for the light grain sample, and

From the pebble cement slabs, the coolest was the one with a surface of white gravel (39.6 oC, Tair+5.1 oC), while the warmest was the one with green and grey gravel (53.7 oC,

The cement blocks used had two different shapes, rectangular and square. The lower limit of the temperature of the white samples and that of the upper limit of the grey-coloured ones determined the range of the surface temperatures of the different colours. White cement blocks reached mean maximum surface temperatures of 41 to 42 oC (Tair+7 to 7.5 oC), while the grey ones were significantly warmer, and their mean maximum temperatures around

This study consisted of four ceramic blocks, two beige and two brown ones, with different thickness (3 and 5 cm). It can be seen (Table 2) that the different thickness of the samples had an insignificant effect (less than 1 oC difference) on their mean maximum and mean surface temperatures. The beige samples had mean maximum temperatures of about 43 oC around

The timber products, which were included in this study, were boards of tropical hardwood (teak and merbau). The merbau sample recorded very high mean maximum surface temperatures, of about 57.4 oC (Tair+22.9 oC) and were comparable to those of the lightcoloured, sandy earth sample. The teak sample was relatively cooler with mean maximum temperature of about 52,9 oC, i.e, Tair+18.4 oC. Obviously the wood samples had high mean

The new asphalt concrete sample was black, and for this reason had very high mean maximum temperature of 61.8 oC, Tair+27.3 oC and mean temperature of 46.7 oC, Tair+15.5 oC, While the weathered asphalt sample was significantly cooler, having a mean maximum temperature of 50.6 oC (Tair+16.1 oC) and a mean temperature of 40.3 oC (Tair+9 oC). The differences between the new and the weathered samples were larger than 10 oC, for the

Asphalt water-proofing membranes recorded the highest surface temperatures among all the samples. All the samples apart from the one with the polished aluminium facing (mean maximum temperature equal to 46.8 oC, Tair+12.3 oC) recorded temperature exceeding the mean maximum surface temperature of 65.5 oC (Tair+31 oC). It should be noted, though, that the samples were placed on an extruded polystyrene slab, which differs from their actual placing practice on a concrete substrate. As a result, the temperatures that were measured may be higher than those, which would have been measured if the materials were

surface temperatures of 40.8 oC and 43.9 oC, for the teak and merbau, respectively.

mean maximum, and around 7 oC, for the mean surface temperatures.

54.8 oC (Tair+20.3 oC) for the heavy-grain one.

noon were about 50 oC (Tair+15 to 17 oC).

noon, while the brown-coloured ones were warmer, with 48 oC.

**2.3.4 Ceramic products** 

**2.3.5 Wooden products** 

**2.3.6 Asphalt products** 

placed on a more conductive substrate.

Tair+19.2 oC).

The vegetal surfaces used for the study were two samples of grass placed on a 4cm thick earth substrate. One of the samples was regularly irrigated, while the other was not. The mean maximum surface temperatures of the samples were very close, about 40 oC (Tair+5.5 oC), while their mean temperatures were lower than the air temperature by less than 1 oC. After sunset (20:00), the samples were significantly cooler (about 5 oC) than the air.



Table 2. Overview of the experimental surface temperature measurements on samples of paving materials.
