Silica polymer bonding of stressed silica grains: An early growth of intergranular tensile strength

TitleSilica polymer bonding of stressed silica grains: An early growth of intergranular tensile strength
Publication TypeJournal Article
Year of Publication2015
AuthorsR Guo, and T Hueckel
JournalGeomechanics for Energy and the Environment
Volume1
Start Page48
Pagination48 - 59
Date Published01/2015
Abstract

Laboratory tests on microscale are reported in which millimeter-sized amorphous silica cubes were kept highly compressed in a liquid environment of de-ionized water solutions with different silica ion concentrations for up to four weeks. Such an arrangement simulates an early evolution of bonds between two sand grains stressed in situ. In-house designed Grain Indenter-Puller apparatus allowed measuring strength of such contacts after 3-4 weeks. Observations reported for the first time confirm a long-existing hypothesis that a stressed contact with microcracks generates silica polymers, forming a bonding structure between the grains on a timescale in the order of a few weeks. Such structure exhibits intergranular tensile force at failure of 1-1.5 mN when aged in solutions containing silica ion concentrations of 200-to 500-ppm. The magnitude of such intergranular force is 2-3 times greater than that of water capillary force between the same grains.

DOI10.1016/j.gete.2015.02.002
Short TitleGeomechanics for Energy and the Environment