Hydration and mechanical properties of high content nano-coated cements with nano-silica, clay and calcium carbonate

Nano-modified cements have gained significant interest due to their ability to enhance fresh and hardened properties and it is suggested that for a given nanomaterial, matrix or application type, there exists an optimum content where further dosing of nanomaterials could cause agglomeration, deterring performance. In this work, we introduce a novel nano-coating dry dispersion method and compare it against conventional sonication in aqueous form to evaluate their effect on hydration and mechanical properties for mixtures prepared with nanoclay, nanosilica or calcium carbonate nanoparticles at 4 wt%. The results show that mechanical perfor-mance is sensitive to the dispersion method, driven by changes to early hydration kinetics. The degree of in-fluence of the dispersion method on hydration kinetics was also found to be dependent on the nanomaterial type, where sonication in water was more mechanically favorable for silica and calcium carbonate nanoparticles and dry dispersion was more favorable for nanoclay.

Automated summary

In this study, a novel nano-coating dry dispersion method was introduced and compared to conventional sonication in water to evaluate their effect on hydration and mechanical properties of nanoclay, nanosilica, and calcium carbonate nanoparticles in cement mixtures. The results showed that mechanical performance was sensitive to the dispersion method, influenced by changes in early hydration kinetics. The influence of the dispersion method on hydration kinetics also depended on the type of nanomaterial, with sonication in water being more favorable for silica and calcium carbonate nanoparticles, while dry dispersion was more favorable for nanoclay.