|Title||Silica polymer bonding of stressed silica grains: An early growth of intergranular tensile strength|
|Publication Type||Journal Article|
|Year of Publication||2015|
|Authors||R Guo, and T Hueckel|
|Journal||Geomechanics for Energy and the Environment|
|Pagination||48 - 59|
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.
|Short Title||Geomechanics for Energy and the Environment|