Stress–Strain Model for Geopolymer Mortar under Active Confinement

Abstract

A stress–strain model is developed for geopolymer mortar subjected to uniaxial compressive loading with active confinement. The model was developed using the triaxial test carried out on cylindrical geopolymer mortar samples cast with different weight percentages of slag and fly ash. The samples were tested under four levels of confining pressures (i.e., 0, 5, 10, and 15 MPa) to study the effect of confining pressure on peak stress, peak strain, volume change, modulus of elasticity, and Poisson’s ratio. The stress–strain behavioral model for geopolymer mortar together with the functional relationship for model parameters with confinement ratios is developed. The developed strain–strain model shows good agreement with the experimental results. Further, the modulus of elasticity and Poisson’s ratio are linearly varied with confining pressure. Also, the normalized volumetric strain factor increases linearly with the compressive strength. The obtained experimental results demonstrate significant improvement in strength and ductility due to confinement for geopolymer mortar.