**2.3.3 Cement products**

The concrete samples, which were tested, comprised of white, light-weight concrete (density = 320 kg/m3) and of grey, dense concrete (density = 2400 kg/m3). It is interesting to note (Table 2) that even though the light-weight sample had a lighter colour than the dense concrete one, its surface temperatures were higher (47.1 oC and 12.6 oC higher than the air temperature, compared to 44.4 oC, i.e. Tair+9.9 oC). The mean surface temperatures of the materials were similar and about 36.5 to 37 oC (5 to 6 oC higher than the mean air temperature).

Among the various cement slabs, the coolest was, as expected, the simple, white one. Its mean maximum surface temperature was higher than the air temperature by only 3.3 oC (37.8 oC), while its mean temperature was higher than the mean Tair by only 1 oC (32.3 oC). From the four samples (white, yellow, red and grey), the one with the highest mean maximum temperatures was the red sample (46.5 oC, Tair+12 oC). The striped / textured cement slabs had similar temperature fluctuation with the simple ones (Table 2). This is consistent with the findings of Doulos et al.(2004) who demonstrated that the effect of texture on the surface temperatures of building materials exposed to solar radiation is not statistically important.

The temperatures of Mosaic (terrazzo) slabs with two different grain sizes, and four different colours (white, yellow, red and grey), were measured. The white slabs were obviously the coolest, with mean maximum temperatures of 38.1 oC (Tair+3.6 oC) for the 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 54.8 oC (Tair+20.3 oC) for the heavy-grain one.

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, Tair+19.2 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 noon were about 50 oC (Tair+15 to 17 oC).
