Cement Hydration–Based Micromechanics Modeling of the Time-Dependent Small-Strain Stiffness of Fly Ash–Stabilized Soils

Abstract

A contact mechanics model, based on the Hertzian elastic contact theory and cementation coating development at particulate scale, was established to predict the time-dependent small-strain stiffness of Class C fly ash–stabilized soils during curing. The cementation coating development model was developed at particulate level based on the Arrhenius law to predict the contact radius growth. A hyperbolic time–temperature relationship was proposed to capture the temperature change of fly ash–stabilized soils and links the pozzolanic reaction rate with curing time. Model-predicted small-strain stiffness was evaluated through both published and experimental test results with good success. The micromechanics modeling indicated that the small-strain stiffness of fly ash–stabilized soil depends on the contact area between fly ash and soil particles and the soil particles’ shear modulus. Most of the small-strain stiffness of the stabilized soil was developed within the first 7 days of curing. In addition, a parametric study and a sensitivity analysis were carried out, which indicated that the proposed contact mechanics model was reliable and robust for predicting the time-dependent small-strain stiffness of soils stabilized with Class C fly ash (or other cementitious stabilizers).