Effect of the particle interactions on the structuration and mechanical strength of particulate materials

¹ FAST, Univ Paris-Sud, CNRS UMR 7608 - F-91405, Orsay, France
² Department of Geological Sciences, University of Idaho - Moscow, ID, USA

Received: 11 September 2016
Accepted: 19 December 2016

Abstract

We investigate the effect of the particles interaction on the mechanical strength of particulate materials. Starting from a dispersion of charged particles, the interparticle force can be modulated by the addition of ionic species. The structuration of the medium is then governed by the competition between drying and gelation processes. Rheological measurements show that addition of ionic species boosts the aggregation dynamics into a solid state and changes the structural properties of the final material. This last point is highlighted by precise measurements of i) the mechanical properties of particulate materials through crack pattern quantification, supported by indentation testing, and ii) the permeation properties during the drying process in a controlled geometry. In particular, these results show a decrease of the drained elastic modulus and an increase in the pore size when the ionic species content in the particulate material is increased. Hence, we show that the solid structure behaves mechanically as a network whose pore size increases when the electrostatic repulsion between particles is decreased. These results are consistent with the fact that the way particulate materials are structured determines their mechanical properties.