Influence of hydration and water content on the brightness of hardened cement paste

Figure: c’t labs 2015

Fig. 1: CIE-L*a*b* color space

Figure: c’t labs 2015

Figure: Leibniz Universität Hannover

Fig. 2: Visual impression of the color of individual cements and additions

Figure: Leibniz Universität Hannover

Fig. 3: Brightness and/or L* value unhydrated cement types as function of the C4AF-content (findings of own investigations and findings from literature)

Figure: Leibniz Universität Hannover

Fig. 4: Brightness and/or L* value of unhydrated cements and the hardened cement paste made of them (w/c = 0.40)

Figure: Leibniz Universität Hannover

Fig. 5: Thinning effect (L*_hyd./L*_unhyd.) as function of the clinker content of various cement types (left) and the Fe₂O₃content (right)

Figure: Leibniz Universität Hannover

Fig. 6: Comparison of brightness and/or the L* values of unhydrated cements with hydrated hardened cement pastes with various w/c ratios from 0.30 to 0.60

Figure: Leibniz Universität Hannover

The coloration of concrete surfaces is a primary architectural feature. This paper investigates and quantitatively evaluates the influences of hydration and water content on the resulting color of hardened cement paste by meansof calorimetric parameters.

Modern concrete construction elements are subject not only to wide-ranging requirements but must frequently satisfy demanding aesthetic expectations such as a defined color. In this context, the color of concrete surfaces is a primary architectural feature. On concrete elements manufactured with a smooth, non-absorbent form fabric, a thin layer of cement paste or hardened paste forms on the surface of the building component. This is essential for the visual impression, and especially for the coloration and/or brightness of the construction element.

On the basis of colorimetric parameters,...