Mechanical behavior of granular materials reinforced by disposable face-mask chips

Abstract

Recently, there has been a growing interest in utilizing disposable face masks as a reinforcing additive to enhance the engineering performance of granular soils. This thesis investigates the mechanical behavior of face mask chips-sand mixture (MSM) from experiments to constitutive modelling. The length to width ratio of mask chips is focused as a main factor in this thesis when preparing MSM samples mixed with Fijian sand. A series of drained triaxial tests is conducted to examine the influence of mask chips on mechanical behavior and properties of MSM. Then, a series of drained biaxial tests is also conducted to examine the influence of shear mode on mechanical behavior and properties of MSM. Next, the critical state theory and a non-associated flow rule are adopted to model the behavior of MSM within the framework of elastoplasticity. A new parameter (pR) is introduced into the yield function, plastic potential, critical state line and elastic modulus of SIMSAND model to characterize the tensile strength induced by mask chips. As a result, the strength and deformation characteristics of MSM with different relative densities under various loading conditions are properly modelled. All results demonstrate that the proposed model is applicable to construction projects relating to MSM.