The chemical reactivity of cement is relevant in describing the progress of early age reactions and microstructure development. The microstructure in turn, dictates the performance of and service life of a concrete material. However, the chemical reactivity, and to some extent, the composition of the cement particles is size-dependent. Since reactivity is a key variable which drives the progress of reactions, it would be valuable to fractionate cementing minerals (particulates) into well-defined size ranges, wherein, by eliminating aspects of size distribution, the mixed influences of surface area (i.e., particle size) and chemistry (i.e., particle composition) on reactivity can be unraveled.This study applies a newly developed microfluidics based inertial separations method, first developed for cellular biotechnological applications, to the fractionation of cement particles, based on size. Inertial microfluidic separation uses a unique balance of inertial lift forces that lead to size dependent dynamic equilibrium positions within the cross-section of a high aspect-ratio channel. This research describes device designs and protocols to achieve separations of cementing particles to unique equilibrium positions within the lateral space of the devices, from which they can be more easily retrieved in a size-dependent manner using symmetric outlets with tuned fluidic resistances.   Special focus is placed on establishing the applicability of this method to: (1) the separation of cementing powders to assess the applicability of the procedure and (2) establishing the yield, efficiency and separation fidelity of the method as functions of parameters such as the fluid flow rate and solid loading in liquid suspensions.

Application of inertial microfluidics for continuous separation of inorganic mineral particles

247th National Meeting (2014)

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