Xianping Liu, Hanqing Gao, Hervé Fryda, Peiming Wang
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引用次数: 0
Abstract
This study investigates the surface whitening mechanism of ettringite rich decorative mortars. Surface whitening was triggered through an exaggerated test scenario with a highly porous simplified mortar and a series of wet/dry cycles. Based on correlative light-electron microscopy observation, soak solution and mineralogical composition analyses, a mechanism is proposed: surface whitening is due to large agglomerates (>100 μm) of further hydrates (AFt phase and AFm phase) being formed in the large pores of the mortar surface during the drying process. The degree of surface whitening does not follow a continuous increase over cycle numbers, but rather evolves to a maximum after which more cycles lead to reduced surface whitening. This surface clearing and reduced whitening is explained by the disappearance of the hydrate agglomerates caused by full carbonation of AFt phase and AFm phase, transforming to small crystals of CaCO3 and secondary Al(OH)3, releasing the color of the pigments.
期刊介绍：
Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.
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