How clay particulates affect shear jamming and the coiling stability of yield stress-matched cementing suspensions

Published

March 25, 2020

Author(s)

Iman Mehdipour, Hakan Atahan, Narayanan Neithalath, Mathieu Bauchy, Edward Garboczi, Gaurav Sant

Abstract

The remarkable increase in the flow resistance of dense suspensions (jamming) can hinder 3D- printing processes on account of flow cessation and filament fragility/rupture in the extruder. Understanding the nature of rheological changes that occur is critical to manipulate flow conditions or to dose flow modifiers for 3D-printing. Therefore, this paper elucidates the influences of clay particulates on controlling jamming and shape stability of dense cementitious suspensions that typically feature poor printability. A rope coiling method with varying stand- off distances was used to probe buckling stability and tendency to fracture of dense suspensions that undergo stretching and bending during deposition. The contributions of flocculation and short- term stiffening on the kinetics of structure formation was deconvoluted using a stepped isostress method. It is shown that the shear stress features divergence with a power-law scaling when the particle volume fraction approaches the jamming limit; ϕ → ϕJ ≈ϕmax. Such a power-law divergence of the shear stress decreases by a factor of 10 with increasing clay dosage. Such behavior in clay- containing suspensions arises from decreasing relative packing fraction (ϕ/ϕmax) and the formation of fractally-architected aggregates, whose uniform arrangement and collective motion control shear jamming and suspension homogeneity, thereby imparting greater buckling stability. These outcomes offer new insights for assessing and controlling shear jamming behavior during slurry-based 3D- printing processes.

Citation

Soft Matter

Volume

16

Pub Type

Journals

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DOI Link

Keywords

rope coiling, rheology, buckling stability, shear jamming, dense suspension, structure formation

Citation

Mehdipour, I. , Atahan, H. , Neithalath, N. , Bauchy, M. , Garboczi, E. and Sant, G. (2020), How clay particulates affect shear jamming and the coiling stability of yield stress-matched cementing suspensions, Soft Matter, [online], https://doi.org/10.1039/c9sm02414 (Accessed December 8, 2024)