Spray-Dry Agglomerated Nanoparticles in Ordinary Portland Cement Matrix

Abstract

Nano-sized particles have got a focus of great interest for the past decade. These ultrafine particles can have an effect in multiple ways on concrete technology. Although most of the effects of nanoparticles are desired, a huge surface area introduced by nanoparticles also incorporates negative effects, such as loss of workability and safety aspects. Agglomeration of nano-sized particles by spray-drying is one potential method to overcome the negative effects. In this study, ultra-fine material was dispersed and agglomerated successfully. Agglomerate structure was analyzed and performance was evaluated with mortar samples. Agglomerated nano-sized material had micron-sized inner porosity, which enabled water penetration into the agglomerates. In water exposure, agglomerates did not dissolve although some of binder glue and dispersing agent leaked out. Water penetration and organic material leaking enabled high reactivity and workability of the agglomerated nanoparticles. In spite of the high reactivity of agglomerated nanoparticles, slightly lower final compression strengths were observed with agglomerated ultrafine particles. The results of this study can be used in concrete technology when further developing admixture technologies and recipe designs. The negative side-effects of the agglomerated nanoparticles can be overcome and accounted for within application areas.