Nanolime mixtures with silica fume or natural pozzola. Preliminary investigations

It is known that hydrated lime (Ca(OH)2) can be activated by reacting with siliceous materials, such as natural pozzolans (P) or silica fume (SF), in presence of water. During the interaction process, the active silica contained in siliceous materials reacts with hydrated lime to form calcium silicate hydrates (C-S-H), according to the pozzolanic reaction. Such reactions, however, could require enough time to complete mainly due to lime particles dimensions. Aim of the present work is to preliminarily study the interaction between commercial silica fume, or natural pozzolan, with nanostructured Ca(OH)2 particles, (nanolime), dispersed in aqueous suspension. The nanolime is synthesized in laboratory by our patented, simple, eco-friendly, time and energy saving and scalable route (RM2011A000370, WO2014020515A1). The interaction is carried out in water, at room temperature, considering a proper water/solid ratio, and different Ca(OH)2/SF(P) ratios in weight. The hydrates phases that forms are investigated at different hydration times by means of several techniques.