Experimental Investigations on the Mechanical Properties of Sand Stabilized With Colloidal Silica

Abstract

Colloidal silica is an innovative stabilizer that is being explored in ground engineering fields. Several experimental investigations were performed to study the effects of colloidal silica stabilization on shear strength as well as hydraulic conductivity of sand. The main aim of the present work is to observe the enhancement in the mechanical properties of colloidal silica-stabilized sand. The paper also aims to explore the optimum pH and corresponding salt content, which provides workable gel time in the field. The primary objective of the present work is to determine the gel time of the colloidal silica solution by adding salt and varying pHs. It was observed that the gel time decreases rapidly as the ionic strength of the colloidal silica solution increases. Sand having relative densities (RD) of 30, 40, and 60% stabilized with four different colloidal silica percentages under a curing period of 3, 7, and 28 days were tested. All test specimens were tested as per standard codal procedures to determine the optimum content of colloidal silica for the enhancement of the mechanical properties of sand. Based on test results, the optimum percentage of colloidal silica at 30% RD, 40% RD, and 60% RD was found to be 12.5%, 11%, and 10%, respectively. Moreover, significant enhancement was observed in the shear strength as well as hydraulic conductivity with the addition of colloidal silica in the sand.