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

Abstract

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 performance is sensitive to the dispersion method, driven by changes to early hydration kinetics. The degree of influence 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.